Table of Content

10 July 2018, Volume 37 Issue 7

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The effects of three pioneer tree species on facilitation and twig and leaf traits of Cyclobalanopsis glauca seedlings in a rocky desertification region of Guangxi, China.

Lü Shi-hong, LI Xiang-qin, BAI Kun-dong, WEI Chun-qiang, ZENG Dan-juan, XU Guang-ping

2018, 37(7):  1917-1924. 

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Cyclobalanopsis glauca is a constructive or dominant species of forest vegetation in karst region of south China, which has strong adaptability to rocky desertification mountain area. An experiment was conducted to explore the effects of three pioneer tree species, i.e.,Delavaya toxocarpa, Leucaena leucocephala, and Zenia insignis, on seedlinggrowth and twig and leaf traits of 1-3 years old C. glauca seedlings in rocky desertification area of southwest Guangxi, China. The results showed that the facilitative effect of three pioneer species on the survival and growth ofC. glauca seedlings were distinct, which was enhanced with the increases of seedling age. The facilitative effect on seedling height growth was greater than on basal diameter growth. The facilitation by D. toxocarpa was greater than by Z. insignis. Some parameters of C. glauca seedlings such as ratio of plant height to basal diameter, average internode length of stems, SPAD value of leaves, average area of single leaves and N content of leaves were larger under three pioneer tree species canopy than that outside canopy, whereas the C/N ratio of leaves was smaller. All these parameters of C. glauca seedlings were significantly different (P<0.05) between beneath D. toxocarpa or L. leucocephala and outside canopy. The specific leaf area of C. glauca seedlings was significantly greater beneathD. toxocarpa than outside canopy. According to the results of this study and previous studies, D. toxocarpa, L. leucocephala and Z. insignis can be chosen as the nurse plants to improve the establishment of C. glauca seedlings and thus the efficiency of vegetation restoration in rocky desertification region of southwest Guangxi, China.

Spatial distribution and association of Potentilla fruticosaand Taraxacum mongolicumbased on Ripley’s K (r) function.

LIU Min-xia, LI Wen, LIAN Yi-ming

2018, 37(7):  1925-1931. 

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The analysis of spatial distribution and association of species is an important method to study population characteristics, interspecific interaction, species and environmental relationship. Potentilla fruticosa andTaraxacum mongolicum are two major species of subalpine meadow in Gannan. We analyzed the field spatial distribution and interspecific association ofP. fruticosa and T. mongolicum on different slopes using Ripley’s K (r) function. The results showed that the distribution ofP. fruticosaand T. mongolicumwere obviously different in three slope aspects. P. fruticosa population showed a decreasing trend, while T. mongolicum population showed an increasing trend from north to south aspect. On the north aspect, P. fruticosa showed a relatively high degree of aggregation at 0-4.8 m scale and a random distribution at 4.8-5 m scale. On the west aspect, P. fruticosa showed a random distribution at 0-0.6 m scale, aggregate distribution at 0.6-1.6 m scale, and random distribution again at 1.6-5 m scale. On the south aspect, P. fruticosa showed a random distribution throughout the study scales. T. mongolicum showed aggregation distribution at 0-2.8 m scale, random distribution at 2.8-5 m scale on the north aspect, and a random distribution at the whole study scales on the west aspect and south aspect. P. fruticosa and T. mongolicum showed a negative correlation at any scale on north aspect. Both species had no association at the whole study scales on the west aspect. On the south aspect,P. fruticosa and T. mongolicumshowed no correlation at 0-2.4 m scale, and a negative correlation at 2.4-5 m scale.

Sap flow characteristics of Larix principis -rupprechtiiplantation and its impact factors in different slope locations at the south side of Liupan Mountains.

WANG Yun-ni, CAO Gong-xiang, WANG Yan-hui, XU Li-hong, LIU Yong-hong, WANG Xiao-jiang

2018, 37(7):  1932-1942. 

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To accurately estimate whole slope-scale or watershedscale forest transpiration from sap flow measurements at plot scale, especially in semi-humid areas with significant spatial variation in environmental factors, it is necessary to examine differences in sap flow at different slope locations and the driving factors. Based on a field study in five larch (Larix principis-rupprechtii) plantation plots established respectively at the upper (P₁), middle upper (P₂), middle (P₃), middle lower (P₄) and lower (P₅) positions in a southeastfacing slope in Xiangshuihe watershed in the semi-humid region of Liupan Mountains of Ningxia, the sap flow velocity in trees as well as the soil water potential and meteorological factors were simultaneously monitored. During the study period, significant differences among slope positions were found in the daily average sap flow velocity (J_s, mL·cm^-2·min^-1), with an order of P₂ (0.0397)>P₄ (0.0368)>P₃ (0.0325)>P₅ (0.0311)>P₁ (0.0278). The J_s was significantly correlated with the maximum air temperature (T_max), solar radiation intensity (SR), water vapor pressure deficit (VPD), potential evapotranspiration (PET), soil water potential (Ψ), volumetric soil water content (VSM), but was negatively correlated with minimum air temperature (T_min), air relative humidity (RH) and precipitation (P). The correlation coefficients were significantly different among different slope positions. There were significant differences in the degree of J_s responses to environmental factors among slope positions. Decreasing trends in the response of J_s to the daily average air temperature (T), RH, VPD, PET and Ψ  were found by the envelope line analysis with the decreasing slope position. In contrast, increasing trends in the response of J_s to the SR and daily average volumetric soil water content (VSM) were observed. Results from regression analysis and partial correlation analysis showed that variations of J_s in different slope positions were mainly controlled by PETand VPD. The J_s at the upper slope positions was strongly influenced by Ψ and T_max, while that at the lower slope positions was largely affected by SR and VSM. In general, the slopedifference in J_s was caused by soil moisture and meteorological factors. Therefore, it is needed to consider jointly the changes of soil moisture and meteorological factors among the slope positions when we estimate the stand transpiration at the slope scale or watershed scale by upscaling the J_s.

Photosynthetic characteristics of Potentilla anserine in three different meadow ecosystems.

SHI Rui, SU Pei-xi, ZHOU Zi-juan, XIE Ting-ting

2018, 37(7):  1943-1951. 

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Potentilla anserina is a cosmopolitan species and miscellaneous forb in alpine meadow, whose asexual reproduction, space expansibility, and morphological plasticity vary significantly with different habitats. The main aims of this study were to ascertain the photosynthetic characteristics of P. anserine under different alpine conditions and their relationship with the environmental factors, and thus find the main environmental factors influencing their propagation ability. Three types of ecosystems (swamp, wet meadow and dry meadow) were selected in the Zoige Plateau to compare the diurnal changes of photosynthesis in P. anserine. The results showed that the average values of net photosynthetic rate (P_n), transpiration rate (T_r), instantaneous water use efficiency (IWUE) and light use efficiency (LUE) of P. anserinein different habitats in late July were significantly higher than those in late August (P<0.05) due to the stronger radiation and higher atmospheric temperature. In each month, the daily average of P_n of dry meadow was significantly higher than that of wet meadow and swamp (P<0.05). The photosynthetically active radiation (PAR) was significantly positively correlated with P_n in three habitats (P<0.05). In dry meadow, air relative humidity (RH) and soil water content (SWC) also had a significantly positive correlation with P_n (P<0.05). From swamp to wet meadow to dry meadow, P_n, WUE, light saturation point (LSP), photosynthetic time, apparent quantum yield (AQY) and carboxylation efficiency (CE) of P. anserine gradually increased and the light compensation point (LCP) decreased. The variations of all parameters indicated that the photosynthetic capacity of P. anserine was enhanced in relatively dry habitats, and its photosynthetic characteristics were moving in the favorable direction for its growth. Water availability may be an important environmental factor that affects the reproduction ability and coverage of P. anserina.

Changes of seed dormancy of Calligonum junceum in its original habitat.

JUMA Aypaxia, ZHAO Xiao-ying, WANG Jiao

2018, 37(7):  1952-1958. 

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Research in germination responses and dormancy of buried seeds contributes to a better understanding of how the timing of germination and dormancy breaking is controlled in nature. Calligonum junceum, a superxerophilous shrub, is a candidate species for revegetation of the cold deserts of northwest China. Fresh seeds were placed on the surface and buried in soil (3-5 cm) in its natural habitat in July 2015, and exhumed (every six weeks in first year, and every eight weeks in second year, up to September 2017) and tested for germination over a range of temperature (15/5, 20/10, 25/15, 30/15 ℃, respectively). The germination percentage of exhumed seeds was very low at four varying temperatures, indicating the existence of primary dormancy. Most seeds were characterized by both non-deep and intermediate physiological dormancy. Seed dormancy was broken in late autumn, winter or next spring. Seeds exhumed in March had a higher germination percentage. Most seeds (70%) reentered secondary dormancy during summer due to high temperature. Most seeds exhibited annual dormancy/non-dormancy cycles in the natural habitat of Dabancheng, due to seasonal changes of temperature, rainfall and chronic wind. Seeds buried in soil had higher germination rate than that on soil surface, whereas seeds on soil surface had higher germination rate than that buried in soil when there was snowing in winter, which was related to different seasonal fluctuations of soil temperature and humidity.

Evaluation of drought and salt resistance of 10 species from Asteraceae.

WU Xiao-feng, NI Pei, YANG Tao, ZHANG Jin-zhu, ZHOU Zhi-da, ZHENG Guan-ren, MENG Fan-bo, CHE Dai-di

2018, 37(7):  1959-1968. 

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To screen drought and salt resistant flower plants, two experiments were conducted. Drought stress was applied during the seed germination and seedling periods of 10 species from Asteraceae, using PEG6000 solution and potting water control method. Meanwhile, salt stress was processed using NaCl solution. The index of seed germination, the relative permeability of plasma membrane and the activity of antioxidant enzymes of the seedlings were measured. Drought resistance and salt resistance of all the species were evaluated with the method of membership function. The results showed that all measured indices changed significantly under drought or salt stress. Under both drought and salt stresses, the relative conductivity and malondialdehyde (MDA) content increased, with the magnitude of enhancement in the species with stronger resistance being smaller. The activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) differed among species. The drought resistance of different species ranged from strong to weak as following: Cosmos bipinnata>Tagetes erecta >Dahlia pinnatecv. >Cosmos sulphureus> Brachycome iberdifolia>Helianthusannuus >Helichrysum bracteatum > Centaurea cyanus >Gazania rigens> Dimorphotheca sinuata; salt resistance from strong to weak: Cosmos bipinnata>Cosmos sulphureus > Dahlia pinnate cv. >Tagetes erecta>Brachycome iberdifolia> Centaurea cyanus > Helianthus annuus >Helichrysum bracteatum> Gazania rigens>Dimorphotheca sinuata.

Allelopathic effect of aqueous extract from Spartina alterniflora on Skeletonema costatum.

LONG Meng-ling, ZHANG Qi, LIANG Xia, CHEN Xue-ping, HE Chi-quan

2018, 37(7):  1969-1975. 

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We investigatedthe effects of aqueous extract from litter of Spartina alterniflora with different concentrations (0, 0.02, 0.04, 0.10 mg·L^-1) on the growth and physiological characteristics of Skeletonema costatum. The cell concentration of S. costatum, chlorophyll-a content, antioxidant enzyme (superoxide dismutase and peroxidase) activities and malondialdehyde contentwere examined. Moreover, we isolated and identified the algicidal allelochemicals from S. alterniflora. The results showed that the inhibitory effect of the extract of S. alterniflora litter on the growth of S.costatumincreased with the extract concentrations.The inhibitory rate was 69.2% under 0.10 mg·L^-1 of extract. The content of chlorophyll a and the activities of antioxidant enzyme were lower in all treatments than the control, and the content of malondialdehydeincreased in all treatments. The components of allelochemicals from S. alterniflora were mainly composed of long-chain fatty acids, including hexadecanoic acid, linoleic acid, and oleic acid.

Effects of simulated trampling and rainfall on sexual reproduction characteristics of Medicago ruthenica var.inschanica on alpine meadow.

XIAO Hong, XU Chang-lin, ZHANG De-gang, CHAI Jin-long, PAN Tao-tao, YU Xiao-jun

2018, 37(7):  1976-1982. 

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A two-year field experiment was conducted to examine the effects of simulated yak and Tibetan sheep trampling (light, moderate, and heavy trampling) and simulated rainfall (low, average, and high) on sexual reproduction of Medicago ruthenica var. inschanica in a Tianzhu alpine meadow in Gansu Province. The results showed that the plant height, pod length, number of pods per square meter, seed number per pod, 1000-grain weight and seed yield of M. ruthenica decreased with the increases of trampling intensity and the decreases of rainfall. Under low rainfall level, heavy trampling decreased the pod number per square meter by >70% than un-trampling. The 1000-grain weight ofM. ruthenicaseeds under trampling was 13% lower than that of un-trampling. Under low rainfall level, the seed yield of M. ruthenicaunder light, moderate, and heavy trampling of Tibetan sheep was 60.1%, 13.8% and 56.7% higher than that under corresponding intensity of yak trampling, respectively. Rainfall, trampling and their interaction showed significant effects on the height ofM. ruthenica. Moreover, rainfall and trampling significantly affected the sexual reproduction indices of M. ruthenica; however, their interaction effect was not statistically significant. Overall, the negative effect of yak trampling on M. ruthenica sexualreproduction was higher than that of Tibetan sheep under same trampling intensity. The sexual reproduction of M. ruthenicawas inhibited by low rainfall level and heavy trampling.

The quantitative characteristics and interrelation of module of Phragmites australis population in Zhalong Wetland in Heilongjiang.

JIAO De-zhi, YAN Qiu-yue, JIANG Qiu-xu, CAO Rui, YANG Yun-fei

2018, 37(7):  1983-1989. 

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This study investigated ramets, rhizome, and rhizome buds of Phragmites australispopulation in xeric, wet, aquatic, and saline-alkali habitats in Zhalong Wetland by clipping and digging samples. The results showed that ramet density, rhizome length, and the storage, input and dormancy of rhizome buds were the largest in wet habitat while they were the lowest in salinealkali habitat from June to October. The output of rhizome buds was the largest in aquatic habitat and the lowest in saline-alkali habitat. The differences of module numbers among the four habitats and their differential order were relatively stable, suggesting significant environmental effects and a great plasticity in the module level. Meanwhile, different modules coevolved. Ramet density was significantly positively correlated with rhizome length, and storage and input of rhizome buds, but negatively correlated with the amount of rhizome bud dormancy. There was a significantly positive correlation between storage, input and output of rhizome bud and rhizome length. The ramets were formed by the germination of rhizome buds, with the contribution rate of rhizome bud to ramet being 100%. More than 80% of rhizome buds formed new rhizomes. The growth of rhizome can form more rhizome buds. The substitute and change of morphological structure of different components maintain the stability and continuous renewal of the population.

Predicting the potential distribution of Epimedium koreanum Nakai in Northeast China.

XU Xiang, XU Yao, XIE Ting, SUN Qing-qing, TIAN Yong-lan, ZHANG Hua-yong

2018, 37(7):  1990-1996. 

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Understanding species distribution and its main influencing factors is important basis for the rational conservation and utilization of wild resources. Epimedium koreanum Nakai is an important medicinal plant resource in Northeast China. Predicting the potential distribution of E. koreanum and clarifying the driving factors can provide scientific basis for the conservation and exploitation of this species. In this study, we predicted the potential distribution and suitability grades of E. koreanum in Northeast China based on 15 occurrence records, 19 climatic factors and six soil factors using the Maximum Entropy (MaxEnt) model. We found that the potential distribution of E. koreanum were mainly located in eastern Liaoning and southern Jilin with an area of 170270 km_². The core suitable habitats of E. koreanum were located in the temperate deciduous broad-leaved forests of eastern Liaoning and southern Jilin, with an area of 80102 km². The precipitation of the driest month and organic carbon content in topsoil were the major climatic and soil factors influencing its potential distribution, respectively. Our results will provide scientific basis for the habitat conservation and artificial cultivation of E. koreanum.

Responses of growth and osmoregulatory substances of Suaeda heteroptera to salt concentrations in wetlands.

SU Fang-li, SUN Xu, SUN Quan, LI Hai-fu, WANG Tie-liang

2018, 37(7):  1997-2002. 

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Suaeda heteroptera wetland in the Liaohe River Estuary is the main habitat of the endangered Black-headed Gull, which is substantially influenced by the salinity in sealand intersection zone. The wetland has been seriously degraded in recent years. It is important to uncoversuitable range of salinity forS. heteroptera growth so as to protect Black-headed Gull. In this study, growth simulators were used to examine the effects of saline solution on the growth and physio logical indices of S. heteroptera during the whole growth period treated by saline solutions with five concentrations of 0, 150, 300, 450 and 600 mmol·L^-1. The results showed that the height and root length of S. heteroptera reached the maximum at the concentration of 300 mmol·L^-1, being 45.6 cm and 14 cm respectively. At such a concentration, the contents of free proline, soluble sugar and soluble protein in both shoots and roots of S. heteroptera were the highest. The contents of the three osmoregulatory substances were 0.82 vs. 0.58 mg·g^-1, 8.46 vs. 6.86 mg·g^-1, and 22.26 vs. 19.36 mg·g^-1 in the shoots and roots, respectively. The height, root length, and contents of the three osmoregulatory substances of S. heteroptera were reduced at the concentration of 450 mmol·L^-1. At the concentration of 600 mmol·L^-1, S. heteroptera grew slowly with yellow stem and leaf abscission and even some plants died. All the growth indices and the contents of osmoregulatory substances remained an upward trend when the salt concentration was less than 300 mmol·L^-1. Our results indicated that suitable concentration of salt for the growth of S. heteroptera was between 150 and 450 mmol·L^-1, with the best effects at 300 mmol·L^-1  and the upper limit was 600 mmol·L^-1.

Simulation of light response of photosynthesis for greenhouse tomato leaves under high temperature and high humidity stress.

YANG Shi-qiong, YANG Zai-qiang, CAI Xia, WANG Lin, ZHOU Xiao-dong

2018, 37(7):  2003-2012. 

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To reveal the effects of high temperature and high humidity on light response of photosynthesis of tomato leaves, an experiment with tomato cv. ‘Jinfen 5’ was carried out in artificial climate chamber. We set a high temperature level of 41 ℃ (daytime)/18 ℃ (nighttime), three levels of relative air humidity of daytime (50%±5%, 70%±5%, 90%±5%), and four levels of experimental duration (3, 6, 9, 12 d), with 28 ℃/18 ℃, 50±5% as control (CK). The light response curve of leaves was measured. We selected CK and different treatments with air humidity levels at 6 days and 12 days as examples, and compared the function of four photosynthetic models. The model with the best simulation effect was used to simulate the light response parameters. The results showed that different models had different adaptability to different high temperature and high humidity. Different light response parameters of the simulation results varied across the models. Comprehensively, the modified rectangular hyperbola model was the best, followed by rectangular hyperbola model, non-rectangular hyperbola model, the exponential model. With the increases of humidity, α, P_max, LSP first increased and then decreased, LCP first decreased and then increased, and R_d had no obvious pattern. Our results confirmed that when the maximum air temperature rose to about 41 ℃, appropriate increase in air relative humidity to 70%±5% could effectively reduce the heat stress on the damage to photosynthetic mechanism of tomato.

Effects of intercropping sugarcane on functional diversity of maize rhizosphere microorganisms.

ZHENG Ya-qiang, DU Guang-zu, LI Yi-fei, CHEN Bin, LI Zheng-yue, XIAO Guan-li

2018, 37(7):  2013-2019. 

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The metabolic function diversity of maize rhizosphere microorganisms in maize monoculture system and maize/sugarcane intercropping system was examined in Yuanjiang and Longchuan counties of Yunnan Province by Biolog-ECO techniques. The results showed that the average well color development (AWCD) of microbial communities in rhizosphere soils in intercropping maize increased by 28.50% and 42.32% than that in monoculture system at both sites, respectively. The Shannon index of rhizosphere microorganisms in intercropping maize system was higher than that in monoculture system at both sites. The utilization rate of 22 carbon sources by rhizosphere microorganisms increased, while the utilization rate of other two carbon sources decreased in intercropping system than in monoculturesystem. However, seven kinds of carbon sources had no consistent pattern in utilization rate between intercropping and monoculture systems in both sites. Intercropping increased the carbon source utilization rate than monocropping, but with geographic differences. The results of principal component analysis (PCA) showed that the rhizosphere microbial community composition and metabolic function were different between intercropping and monoculture systems. In conclusion, diversity, activities, and metabolic function of soil rhizosphere microbial community were higher in the maize/sugarcane intercropping system than that in maize monoculture. The results will provide a theoretical basis for examining the effects of maize/sugarcane intercropping on the activity of rhizosphere microbial community.

Effects of drought and waterlogging stress on root growth of cotton.

HUANG Tao-xing, WANG Xiu-gui, WU Hao, ZHANG Jin-xing

2018, 37(7):  2020-2029. 

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To clarify the effects of drought and waterlogging stress on root of cotton at flowering and boll-setting stages, an experiment with drought, waterlogging and abrupt droughtflood treatments was carried out in the Irrigation and Drainage Experiment Station of Wuhan University in 2016. Minirhizotron systems were used to conduct in situ and long-time monitoring of root systems and digging method was used to validate the obtained data. The images obtained by minirhizotron were equivalent to a 3.3 mm depth of field (DOF) around the tube. From the squaring stage to boll opening stage, root growth resembled an S-shaped curve, with the fastest growth in the flowering stage. The cotton roots were mainly distributed in 0-30 cm soil layer, accounting for 70%-80% of the total amount of the roots. The total root length and total root surface area under different treatments were in the order of waterlogging > waterlogging after drought > control > drought. Waterlogging led to rapid growth of roots at the upper soil layer, especially for those with diameter of 0.2-0.4 mm. Drought decreased root length density, increased root diameter and the proportion of roots in deeper layers, which caused the barycenter of the roots to move downwards. The root growth rate was larger in the drought treatment followed by waterlogging treatment compared to the control group, implying that waterlogging has a compensatory effect on root growth following previous drought stress.

Analysis of the R2R3-MYB genes in soybean roots in response to Cd stress.

DING Jie, ZHANG Xiao-na, PIAO Chun-lan, CUI Min-long, GAO Zhen-ri

2018, 37(7):  2030-2039. 

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Low concentrations of the non-essential heavy metal cadmium (Cd) generate an extremely high level of toxicity, which affects the growth and development of plants. The MYB  family is one of the largest families of transcription factors in plants. Related studies in recent years have highlighted its role in a wide range of biological processes. In this study, to gain a better understanding of the role of MYB genes in Cd stress responses in soybean roots, 7-day-old soybean seedlings were treated with a culture medium containing 75 μmol·L^-1 of Cd for 0, 4, 8, 12, and 48 h, respectively. Transcriptome sequencing and analysis of the soybean roots were subsequently performed using the Illumina HiSeq high-throughput sequencing system. We identified 16 R2R3-MYB genes closely linked to Cd stress responses. An amino acid sequence analysis showed that all 16 MYB transcription factors composed of four conserved elements and contained the conserved R2 and R3 domains. A phylogenetic analysis was conducted using the subgroup classification of R2R3-MYBgenes in Arabidopsis thaliana as reference; the genes belonged to seven subgroups, namely S1, S2, S8, S15, S17, S20, and S22. Under Cd stress, changes in expression levels of at least twofold occurred in all the 16 R2R3-MYB genes. In particular, expression was downregulated in six genes, with the highest degree of downregulation being 17-fold, and upregulated in the other 10 genes, with the highest degree of upregulation being 11 old. Further analysis revealed that MYB genes in soybean roots primarily alleviated Cd toxicity through regulating Cd absorption, transport, and detoxification. Our results will provide both genetic resources and a theoretical basis for the breeding of Cdresistant soybeans.

The community diversity of butterflies in Jiufeng Mountain of Baotou.

WANG Xu-na, QIAN Hong-ge, BAI Xiao-shuan

2018, 37(7):  2040-2044. 

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The species diversity of butterfly in Jiufeng Mountain of Baotou was examined based on the investigation in five transect lines: (Ⅰ) Zaogou Toll gate, (Ⅱ) Nangou Gate, (Ⅲ) Lingying Temple, (Ⅳ) Zaogou Road 33 km, (Ⅴ) Jiufeng scenic area. For all the individuals of butterfly  collected, there were 37 species belonging to four families and 34 genera. Among them, Neolycaena davidiand Erynnis popoviana were first recorded in Inner Mongolia. In terms of the richness of genera and species, Nymphalidae was the dominant family, with the highest genus richness (16) and species richness (19). Hesperiidae was the rare family, with the lowest genus richness (4) and species richness (4). Nymphalidae had the highest diversity index (4.8803) and evenness index (0.8517) and Pieridae had the highest dominance index (0.8784), while Pieridae had the lowest diversity index (1.0544) and evenness index (0.2942). Among different transect lines, Lingying Temple (Ⅲ) had the highest indices of family diversity (1.1052), genus diversity (2.2656) and species diversity (2.2951). With the seasonal change, speciesnumber (25), diversity index (2.3476) and species richness (4.0297) peaked in July. Among the 37 species, 27 were Palearctic species, accounting for 72.97% of the total species; 10 were widely distributed species, responsible for 27.03% of the total species and none was Oriental species, suggesting that the butterfly fauna was mainly Palearctic in the area.

The monthly dynamics of lawn insects and their relationship with birds at Nanjing Lukou International Airport.

XU Jie, GAO Jin, LIU Jin-wei, WU Cong, WANG Qi, ZHENG Hui, WANG Bei-xin

2018, 37(7):  2045-2050. 

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Exploring the temporal dynamic relationship between birds and insects helps the control of bird occurrence from a food-chain perspective and the risk reduction of birdair craft collisions. We monthly sampled lawn insects, recorded the airfield bird guild and inspected diets of bird specimens from March to November, 2015 at Nanjing Lukou International Airport. A total of 26221 insect individuals representing 123 species, 99 families, and 13 orders were collected and identified. Hemiptera, Hymenoptera, Diptera, Coleoptera and Dermaptera were the most abundant orders. Tingidae, Chironomidae, Aphididae and Lygaeidae were the most abundant families. The monthly variation of insect density and richness showed a unimodal pattern, with aboveground insects peaking in August (10 ind·m^-2 and 59 species) and ground insects peaking in September (113 individuals per cup and 36 species). A total of 41 bird species belonging to 21 families and nine orders were recorded in the regular observation with the monthly dynamic peaked in the months of July to October. Dietary analysis revealed that insects, and weed seeds of Leguminosae and Gramineae were the main foods consumed by airfield bird. Pearson correlation analysis showed monthly bird individuals significantly and positively related to the total monthly insect individuals, as well as the monthly insect individuals of the orders of Orthoptera, Hymenoptera, Colleoptera and Hemiptera, respectively. Generalized linear model (GLM) showed that monthly dynamics of bird occurrence at Lukou Airport can be well predicted by Orthoptera individuals. Our results demonstrated close relationships between airfield bird occurrence and lawn insects. It would be helpful for reducing airfield bird occurrence by effective insect control measures such as pesticides application and regular mowing.

Patch size matters for arthropod composition and diversity in fragmented tropical forests.

MA Zhan-xia, GAN Jian-min, ZHANG Ling

2018, 37(7):  2051-2058. 

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Landuse change and habitat loss are two top threats to biodiversity. Tropical forest is a hotspot for biodiversity but threatened by forest fragmentation. To explore the effects of forest fragmentation on arthropod diversity, we used metabarcoding to investigate the composition and diversity of arthropods underneath nine forest fragments in a rubber landscape matrix in Nabanhe Nature Reserve (Xishuangbanna, SW China). A total of 347 OTUs of 18 arthropod taxa were collected from nine forest fragments. There were 225 OTUs in large forest patches (≥50 hm² in size), 113 OTUs in medium forest patches (10-50 hm²), and 139 OTUs in the small forest patches (≤10 hm²), respectively. Forest patch size significantly affected arthropod richness, with the responses of different arthropod communities to forest patch sizes being varied. The beta diversity of arthropods in larger forest patches was significantly lower than that in smaller patches, whereas there was no significant difference in beta diversity of arthropods between the medium and small forest patches. Our results suggested that large forest patches in tropical regions had positive impacts on both composition and diversity of arthropod community, while small forest patches also deserves to be conserved.

Stomach content characteristics and feeding preference of Chiromantes dehaani in the salt marsh of Yangtze estuary.

ZHANG Yuan, TONG Chun-Fu

2018, 37(7):  2059-2066. 

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Chiromantes dehaani is one of the dominant species in the salt marsh of the Yangtze estuary. Its feeding habit and behavior characteristics play an important role in the maintaining of ecosystem structure and function. In this study, we analyzed the feeding habit of C. dehaani and influencing factors through field sampling in different habitats in the north tidal flat of Chongming Island and laboratory experiment. Results showed that plant leaves were the main food source of the crab, and the sediment took the second place. Tender leaves of common reeds were the most preferred food, accounting for 35.7% of all food consumed, while senesced leaves of the common reeds were the least preferred food, accounting for 6.8%. The food compositions of the crab were different among habitats and genders. In the field condition, the intake of plant leaves by the crab was influenced by its weight, carapace width, and chela height. The results of indoor feeding experiment showed that the crab had significant feeding preference to tender leaves of the common reeds (p<0.05), which was mainly influenced by its gender. Its feeding preference on senesced reed leaves was influenced mostly by its weight, carapace width, and chela height. We concluded that the feeding habit of C. dehaani bared a certain preference, which was affected by multiple factors including the characteristics of the food and its growth.

Spatial and temporal variation of fatty acid composition in Argentine hake (Merluccius hubbsi) in the Southwestern Atlantic Ocean during austral spring and summer.

WANG Shao-qin, YANG Qing-yuan, ZHU Guo-ping, SONG Qi

2018, 37(7):  2067-2075. 

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Argentine hake (Merluccius hubbsi), one of the important fish species with highly commercial value, is the target species for bottom trawl fishery in southeastern Atlantic Ocean. In this study, gas chromatography-mass spectrometry (GC-MS) was used to measure the fatty acid composition of Argentine hake. We examined the potential difference of each fatty acid composition, including saturated fatty acids (SFA), mono-unsaturated fatty acid (MUFA) and poly unsaturated fatty acid (PUFA) across different standard lengths, months and latitudes. The results showed that the contents of different types of fatty acids was in order of ∑PUFA>∑SFA>∑MUFA. Specific fatty acids with higher levels included C22:6n3 (docosahexaenoic acid, DHA), C16:0, C18:1n9c, C20:5n3 (eicosapentaenoic acid, EPA) and C18:0. Among them, DHA had the highest content, accounting for 35.27% of total amount of fatty acids. The high ratio of PUFA/SFA suggested that Argentine hake can be considered as the supplementary material for PUFA. Across different standard length classes, higher contents of ∑SFA and ∑PUFA were found in small standard length class (20.1-30.0 cm), where DHA and EPA in ∑PUFA were relatively higher, making n-3/n-6 enlarged, indicating that smaller individuals were more nutritious than larger ones. Except for n-3/n-6, there was no significant difference of the content of fatty acids across months. The highest n-3/n-6 ratio was found in January, indicating that muscle tissue of Argentine hake had higher nutrition in this month. There was no significant difference in contents of each fatty acid across different latitudes and sea surface temperatures.

The spatial heterogeneity of  main soil chemical properties in secondary forest in montane region of eastern Liaoning Province in China.

ZHANG Shu-yuan, QIN Sheng-jin, ZONG Guo, CAI Jun-qi, BAI Xue-jiao

2018, 37(7):  2076-2082. 

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Studies of spatial variability of soil chemical properties are not only valuable for understanding soil formation, structure, and function, but also for understanding plant soil relationships. We analyzed the spatial heterogeneity of eight main soil chemical properties in a 4 hm² secondary forest plot in the montane region of eastern Liaoning Province. The results showed that the soil was slightly acidic; the variation of pH was weak, while the variations of organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK) were moderate. Spherical model fitted best for soil pH, and exponential model fitted best for the other soil chemical properties. Soil AK, pH, and OM showed moderate spatial autocorrelation, while the other chemical properties showed strong spatial autocorrelation. Soil pH showed a relatively uniform distribution pattern, while the distribution patterns of the other chemical properties were similar, being high in east but low in west of the plot. Soil temperature and spatial distributions of tree seedlings may be the main factors driving the spatial distribution of soil chemical properties in this area.

Relationship between soil nutrients and enzyme activity in Robinia pseudoacacia plantation.

WANG Tao, MA Yu-dan, XU Ya-dong, GUO Shu-juan, WANG Wei-yu, HAN Xin-hui, YANG Gai-he, WANG Xiao-jiao

2018, 37(7):  2083-2091. 

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To reveal the process of soil bioactivity and fertility restoration of Robinia pseudoacacacia plantation in loess hilly region, using the space for time substitution method, a chronosequence of 17, 27 and 42 years old of R. pseudoacacia plantation was selected, with a sloping cropland (0 year old) as control. We examined the dynamics of carbon, nitrogen and phosphorus contents in 0-30 cm soil layer, and the relationship between the contents of carbon, nitrogen and phosphorus and the activities of four enzymes. The results showed that soil nutrient content and enzyme activity of R. pseudoacacia plantation decreased from 0-10 cm to 20-30 cm soil layer. Soil organic carbon, total nitrogen and dissolved organic carbon in the layer of 0-30 cm increased with the increases of restoration duration, being 1.4, 4.2 and 5.1 times higher than those in sloping cropland, respectively. The content of dissolved organic nitrogen in soil was slightly different among different restoration durations, with a mean value being 1.8 times higher than that in sloping cropland. Similarly, from 15 to 45 years old, the activities of four enzymes in the soil layer of 0-30 cm significantly increased. The increments of alkaline phosphatase and sucrase activities reached 3.4-9.5 times and 8.1-15.6 times, and that of catalase and urease activity was only 0.2-0.3 times and 1.8-2.2 times, compared with that in cropland, respectively. The results of redundancy analysis showed that soil nutrients could well explain the variability of enzyme activity, with a significantly positive correlation (P<0.01). The effects of soil nutrients on enzyme activity were in order of total nitrogen > dissolved organic carbon > soil organic carbon > soil water content > dissolved organic nitrogen > available phosphorus. The alkaline phosphatase activity was positively correlated with dissolved organic carbon, dissolved organic nitrogen and available phosphorus, which could be used as an index to reflect soil restoration in R. pseudoacacia plantation.

The influence of debris removal on nutrient concentrations and stoichiometric ratios of four understory species in subtropical Chinese fir plantation.

LI Zhang-min, CHEN Fu-sheng, FANG Xiang-min, WAN Song-ze, LI Xiao-dong, WANG Hui-min, BU Wen-sheng

2018, 37(7):  2092-2099. 

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Forest debris and understory vegetation play an important role in forest key processes and plantation management. The influence mechanism of debris management on the understory vegetation is not clear in subtropical plantation. This study was based on a field platform in middle-aged plantation of Chinese fir (Cunninghamia lanceolata) under two treatments (debris removal and control) with four replications. After four years continuous treatments, two dominant herb species (Dryopteris chinensis,Lophatherum gracile) and two dominant shrub species (Ilex pubescens,Callicarpa bodinieri) were sampled in the growing season. The concentrations of NH₄⁺-N, NO₃^--N, available P in rhizosphere and bulk soils, as well as N and P in leaves and roots were measured to explore the responses of roots and leaves in different species. The results showed that debris removal significantly improved the available P in the rhizosphere and bulk soils for the four species (P<0.05), while different species had different responses for the concentrations of mineral N (NH₄⁺-N+NO₃^--N). Debris removal had no significant influence on leaf nutrients, except for reducing leaf P of C. bodinieri, but significantly increased root N and P, except for root P of L. gracile. Furthermore, debris removal improved the root N/P of D. chinensis and L. gracileand the leaf N/P of C. bodinieri. In conclusion, debris removal can enhance the nutrient supply capacities of surface soil in a short time. Root has an earlier and stronger response to soil nutrient and environmental changes than leaf, whereas leaf has a stronger internal stability of nutrient balance than root in Chinese fir plantation.

Contents of soil organic carbon and components in three types of forests in the mountain area of Eastern Liaoning.

YIN You, LIU Yuan-yue, JING Yan-li, WEI Ya-wei, AN Yun-quan, YAN Pin-chu, ZHOU Yong-bin

2018, 37(7):  2100-2106. 

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Soil organic carbon and its components play an important role in carbon cycling of forest ecosystems. In this study, we selected three typical forest types of Eastern Liaoning, including natural secondary forest (broadleaved mixed forest, SF), pure larch plantation forest (LF), and larch and Manchurian ash mixed plantation forest (MF), and collected soil samples of different depths (0-10, 10-20 and 20-30 cm) to analyze the variation of soil organic carbon (TOC) and its active carbon components. The contents of TOC and its active organic carbon in the three forest types all decreased with the increases of soil depth. Among the three forest types, the contents of TOC and its active organic carbon decreased in the sequence of the natural secondary forest > mixed plantation forest > pure plantation forest. The TOC contents in the surface (0-10 cm) were 61.52, 49.22 and 41.16 g·kg^-1, respectively. For active organiccarbon, the contents of particulate organic carbon (POC) were the highest being 20.18, 15.84 and 12.92 g·kg^-1, followed by light fraction organic carbon (LFOC) and microbial biomass carbon (MBC), with the contents being 13.51, 10.04, 8.24 g·kg^-1 and 9.06, 6.13, 5.11 g·kg^-1 respectively. The contents of easily oxidized organic carbon (EOC) were the lowest, being 3.54, 2.78, 2.26 g·kg^-1 in the natural secondary forest, mixed plantation forest, and pure plantation forest, respectively. There were significantly positive relationships between TOC and LFOC, POC, EOC and MBC across the three types of forests (P<0.01).

The role of ecosystem photosynthetic rate and photosynthetic conditions in regulating soil respiration in a sandy grassland.

LIN Li-tao, SUN Xue-kai, LEI Qian, YU Zhan-yuan, ZENG De-hui

2018, 37(7):  2107-2113. 

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Photosynthesis regulates soil respiration by providing substrate for soil respiration, which has received more and more attention. Therefore, photosynthesis becomes an important parameter in constructing soil respiration model. In this study, we assessed the role of photosynthesis in regulating soil CO₂ flux in a Keerqin sandy grassland. The results showed that soil temperature was the most significant factor influencing soil respiration. The temperature sensitivity (Q₁₀ values) dissimilated under different photosynthetic conditions, with nighttime (3.03) > daytime (2.12), daily mean (2.41) > 8:00-10:00 a.m. (2.32). Results from partial correlation analysis showed that photosynthesis was an important factor affecting soil respiration (r=0.72, P<0.01). There was a significantly linear positive correlation between photosynthesis and soil respiration (R²=0.49,P<0.01), with a slope of 0.24. Regression model with adding photosynthesis variable significantly improved the fitting R² from 0.73-0.75 to 0.81-0.85 and the power+exponential function, linear+exponential function, and exponential+exponential function all had a good fitting degree in model selection.

The horizontal distribution of soil physicochemical properties, soil enzyme activities, and microbial biomass in moss crust patch in a temperate desert.

LI Xi-qian, ZHANG Yuan-ming

2018, 37(7):  2114-2121. 

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Moss crust, one of the main types of biological soil crust in deserts, influences sand surface stability, soil water and nutrition distribution, and the growth of vascular plants. In natural conditions, moss crusts mainly occur in patches with different sizes. However, the horizontal distribution pattern and edge effect of the patches remain unclear. In this study, three circles with different distances (r=3.5, 7, and 10 cm, respectively) from the center to the edge of the moss crust patch (about r=10 cm) were settled, and soil physicochemical properties, enzyme activities, and microbial biomass were analyzed. The results showed that: (1) Soil organic matter, total nitrogen and total potassium concentrations were significantly influenced by the edge effect, being higher in the inner and middle circles and lower in the outer circle. There was no significant difference of other soil indicators in the three circles. (2) The activities of urease and catalase in the outer circle were significantly lower than that in the middle and inner circles, while the activities of sucrase and alkaline phosphatase had no significant difference among the three circles. Soil microbial biomass carbon (SMBC) and nitrogen (SMBN) significantly decreased from inner to outer circle, while there was no significant difference between the inner and middle circles. (3) Results from the path analysis showed that soil organic matter concentration was the direct and main factor influencing urease activity. Catalase activity and SMBC were more sensitive to the edge effect, with the direct path coefficient of distance to these two variables being higher than other direct path coefficients (-1.108 and -1.224, respectively). The soil organic matter concentration, pH, and available and total K concentrations had high direct path coefficients for SMBN, with high indirect path coefficients for SMBN via organic matter concentration. Therefore, SMBN was affected by multiple physical and chemical factors and distance. In addition, the residual path coefficients of catalase activity and SMBC were relatively high, implying that other factors being not considered had strong influence on the two variables.

Nitrogenfixation activity of the hermatypic corals associated diazotrophs.

ZHANG Ying, YANG Qing-song, ZHANG Yan-ying, LING Juan, LI Jun-nian, DONG Jun-de

2018, 37(7):  2122-2129. 

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Hermatypic corals are the main constructor of coral reef ecosystems. The nitrogen (N) fixation by hermatypic corals associated microbes can relieve N limitation in oligotrophic tropical waters, and consequently sustain high primary productivity of the coral reef ecosystems. In this study, the acetylene reduction assay (ARA) method was applied to detect the N fixation rate of diazotrophs associated with the corals inhabited in Luhuitou Peninsula, Sanya, Hainan and Nanshazhou, Xisha Island. The concentrations of dissolved inorganic nutrients were measured to explore the relationship between N fixation rate and environmental factors. The N fixation rate of all investigated corals in Luhuitou Peninsula showed no significant seasonal change. There were significant differences in the N fixation rates among Pocillopora damicornis, Porites lutea, and Acropora gemmifera. The highest N fixation rate was detected in Pocillopora damicomis(P<0.05), being 5.925×10^-11 mol C₂H₄·g^-1·h^-1 and 6.471×10^-11 mol C₂H₄·g^-1·h^-1 in summer and winter, respectively. The N fixation rate of Porites lutea(5.401×10^-11 mol C₂H₄·g^-1·h^-1) from oligotrophic Xisha was significantly higher than that from Lunhuitou (1.971×10^-11 mol C₂H₄·g^-1·h^-1) (P<0.01). Our results revealed no seasonal variation of N fixing rate in coral reef ecosystems with high concentration of nutrients. In addition, the high concentration of soluble nutrients in seawater may reduce the N fixation activity in corals.

Purification capacity for treating sewage of urban forest soil in Harbin.

DUAN Wen-biao, DUAN Wen-jing, CHEN Li-xin, SHEN Hai-long, HAN Dong-hui, QU Mei-xue, AMADOU Touré, ZHANG Yu-shuang

2018, 37(7):  2130-2138. 

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To ascertain the purification capacity of urban forest soil of different forest types for treating sewage and provide scientific basis for the configuration of waterfront shelter forests, we selected three forest types (Quercus mongolica plantation, Fraxinus mandshurica plantation, Phellodendron amurense plantation) in the demonstration base of urban forest in Harbin as the research object and bare land as the control. The Majiagou sewage was collected for indoor simulated irrigation. The compositions of soil column leachate following irrigation were measured. The results showed that the removal effects of ammonium in the three forest soils were significant (P<0.05). The ammonium absorbed in the soil column was not different among three forest soils, which was also not significant from the control (P>0.05). The concentration of nitrate in leachate from the soil columns in three forest types and the control increased significantly as compared with the sewage without soil column filter (P<0.01), which increased with the water inflow. The quality of nitrate leached from the soil column of three forest types was lower than that of the control, but the difference was not significant (P>0.05). The pH of leachate from the soil columns of three forest types and the control was significantly lower than that without soil column filter. The dissolved oxygen in leachate from the soil columns of each forest type was higher than that without soil column filter, but the difference was not significant. Except for the Q. mongolica plantation, the redox potential, electrical conductivity, and total dissolved solids in the leachates from soil columns of other two forest types and the control increased significantly compared with the sewage without filtered soil column.

Seasonal variations of soil microbial biomass C and N in different types of water conservation forest in the headstream of Taizi River watershed.

TU Zhi-hua, WEI Yong-jian, FAN Zhi-ping, QIN Yi-ting, WANG Shan-xiang, HAN Qing, ZOU Yi-hua, YANG Zhao-ming

2018, 37(7):  2139-2147. 

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To clarify the growing season dynamics of soil microbial biomass C and N in water conservation forests in the headstream of Taizi River watershed, we measured soil microbial biomass C and N in two soil layers of Larix gmeliniiplantation, natural secondary broadleaved forest, and Pinus tabuliformis plantation from April to September 2016. The relationships between soil microbial biomass and soil nutrient and soil water were analyzed. Our results showed that soil microbial biomass C and N were significantly higher in natural secondary broadleaved forest than that in both coniferous plantations (P<0.05), but all decreased gradually with increasing soil depth. The soil microbial biomass C and N in the three forests varied significantly among seasons, i.e., increased gradually in spring, peaked in summer, and decreased in autumn. The soil microbial biomass C/N in different forests ranged from 1 to 5, showing a seasonal pattern of decrease increasedecrease. Additionally, the microbial biomass C and N had a significantly positive correlation with soil organic carbon, total nitrogen, and soil water content, suggesting that these three variables were important factors affecting soil microbial biomass. The microbial biomass C and N varied among different forest types, with natural secondary broadleaved forest being most beneficial to nutrient accumulation. More attention should be paid to the protection of natural secondary forests and the transformation of the artificial plantations into natural secondary forests in the headstream of Taizi River watershed.

Spatio-temporal differentiation and influencing factors of vegetation net primary productivity using GIS and CASA: A case study in Yuanyang County, Yunnan.

CHEN Feng, LI Hong-bo, LIU Ya-jing

2018, 37(7):  2148-2158. 

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To clarify the changes and driving mechanism of the net primary productivity (NPP) in Yuanyang, Yunnan Province, we simulated the spatio-temporal distribution of vegetation NPP in Yuanyang from 2005 to 2015 based on the improved light energy utilization model (CASA) and MODIS-NDVI data. The correlations between NPP and climate factors or land use types were analyzed. From 2005 to 2015, the spatial distribution of NPP was significantly different in Yuanyang, increasing from the northeast to southwest, with an annual average of 380.57 g C·m^-2·a^-1. The vegetation NPP differed among land use types. The monthly and interannual NPP showed substantial variation. The uneven distribution of solar radiation had greater influence on NPP than that of precipitation during the year. The annual NPP presented a fluctuant increasing trend during the past decade, with an increment amplitude of 0-37 g C·m^-2·a^-1. The overall annual NPP was increased slightly, with an annual growth rate of 29600 kg C·a^-1. With the implementation of returning farmland to forest and grassland, the area of cultivated region with NPP of 200-300 g C·m^-2·a^-1 was decreased, and that of the woodland and grassland with NPP of 300-400 g C·m^-2·a^-1 showed an increasing trend. The change trends of NPP in different areas of Yuanyang could be classified as significant increase (P<0.01), slight increase (P<0.05), and no significant change, of which 29.5% of the area increased significantly, and 16.3% of the area increased slightly. The trend of NPP increasing varied across different vegetation types. The proportions of areas with significantly increasing NPP were 58.1% for woodland,19.2% for grassland, 17.4% for arable land, 11.4% for construction land, and 8% for garden. The changes of NPP were influenced by natural factors and human factors. The correlation coefficient between NPP and temperature or solar radiation was higher than that of precipitation. The large-scale increase of NPP was a result of heat and energy coupling. The comprehensive influence of vegetation characteristics in forested area and human activities including returning farmland to forest and grassland resulted in the greatest seasonal variability of vegetation NPP in forest, which was the main land-use type with significant changes of NPP. Our results provide valuable reference for land use, resources management, and ecosystem reconstruction.

Health rehabilitation and recreation in forests: Concept connotation, product type and development route.

WU Hou-jian, DAN Xin-qiu, LIU Shi-hao, SHU Yong, CAO Hong, HUANG Yan, LU Li

2018, 37(7):  2159-2169. 

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Health China Strategy has risen as a national strategy. Health industry is expected to boom and become new economic growth engine in the future. As an important component of the health industry, health rehabilitation and recreation in forest (HRRF) is new in China in recent years and still in its infancy. Based on existing definitions of HRRF, we systematically expounded the concept, function, and scientific connotation of HRRF, and classified the HRRF products from the aspects of consumption object, product content, and construction subject. Six basic routes were designed for the development of HRRF, including strengthening macro control ofHRRF industry development, constructing good development mechanisms of HRRF, building up featured HRRF products and HRRF complex, strengthening scientific monitoring and construction of talent team, improving the supporting facilities to provide highquality HRRF services, and strengthening publicity and marketing to increase the awareness of HRRF brand. Finally, we discussed the connotation and extension of the HRRF research, HRRF pilot demonstration, the relationship between HRRF base and the existing forest tourism entities or forest nature reserve, the evaluation of HRRF base construction, and the relationship of HRRF development and forest conservation.

Research advances in the impacts of climate warming on rainfed agriculture and agroecology in Northwest China.

YAO Yu-bi, YANG Jin-hu, XIAO Guo-ju, LEI Jun, NIU Hai-yang, ZHANG Xiu-yun

2018, 37(7):  2170-2179. 

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Climaterelated challenges for agricultural ecosystems and regional food safety have become a major concern due to projected global warming characterized by the increase of annual global average land surface temperature. The impacts of climate warming on agricultural development and ecosystems have become a focused issue for society. Studies on the impact and mechanism of climate warming on crop growing periods, morphological characteristics, physiology, yield formation and quality are the scientific basis for identifying the impact of climate warming on agriculture and making policies against climate warming. Based on the basic characteristic of climate warming in Northwest China, we summarized the research advances in the impacts of climatic warming on the growth, physiology, ecology, yield and quality of main food crops, economic crops and special fruit trees, farmland ecological environment, agricultural meteorological disasters, plant diseases and insect pests, and discussed the deficiency in current researches. This review makes a further prospect for the key points in future research on the impact of climate warming on agriculture and agricultural ecology in Northwest China: (1) Sufficiently use simulating, testing, and observing measures to disclose the impacts of multi-factors of climate change on major crops; (2) Study the impacts of climate warming on the physiology and ecology of major crops; (3) Study the responses of agricultural meteorological disasters to climate warming and take risk evaluations on agricultural meteorological disasters and find out countermeasures; (4) Study technological strategy in the refined dynamic agricultural planting regional division, agricultural structural distribution and planting system to cope with the climate warming.

Predation pattern of seed predators on coniferous seeds and their defense adaptation.

TENG Wei, LIU Bei-bei， RONG Ke

2018, 37(7):  2180-2188. 

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In cold temperate regions, seeds of conifers are an important food source for manyanimals because of high oil and protein concentrations. There are mainly two kinds of predationpatterns for conifer seed predators, that is, pre-dispersal predation and post-dispersal predation. The process of animal prey on seeds is an important way for the regeneration of tree species. Seeds that evade predators form corresponding defensive strategies, with seed size, nutrition, fiber content, secondary metabolites and so on being generally strategies for seed protection against predators. These defensive strategies will affect the seed predator’s population dynamics and feeding behavior, and may also lead the seed predator to adapt to the seed defense. Therefore, it is of great significance to study the predation mode of seed predator on seeds of conifers in order to better understand the animal feeding behavior in coniferous forest. Meanwhile, studying the conifer seed defense and seed predator’s adaptive strategy will help understand the relationship between plants and animals.

Review on the effects of low molecular weight organic acids on soil phosphorus activation and mechanisms.

WANG Yong-zhuang, CHEN Xin, SHI Yi, LU Cai-yan

2018, 37(7):  2189-2198. 

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Over the last 30 years, water eutrophication caused by excessive application of phosphorus (P) fertilizer to soil has attracted much attention. Lowmolecularweight organic acids in root exudates can mobilize the accumulated P in soils and thus enhance P availability, which has become a research hotspot. We reviewed recent advances about the activation effects of lowmolecularweight organic acids on soil inorganic and organic P, as well as the activation mechanisms by comparing the changes of different P forms in experiments before and after soil P activation. Release of soil inorganic P induced by low molecular weight organic acids mainly contributes to P transformation from low availability to high availability. However, release mechanisms of soil organic P induced by low-molecular-weight organic acids are still not clear, which needs to be further studied. Future studies should focus on the synergistic mechanisms between low-molecular weight organic acids and P fertilizers. Moreover, more studies are needed on the release mechanisms of soil P (especially organic P) induced by low-molecular-weight organic acids.

A review of the effects of urban landscape pattern on soil fauna diversity.

WU Wen, XIU Chun-liang, HU Yuan-man, LI Chun-lin

2018, 37(7):  2199-2204. 

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Urbanization is one of the main reasons for biodiversity reduction and habitat fragmentation, which changes urban landscapes and ecological processes. Soil fauna is a significant component of urban ecosystems. It could make quick responses to rapid urbanization, being a typical environmental indicator. Due to the complicated disturbance factors of the urban ecosystem, the land use type could not fully reflect local habitat differences of soil fauna. It remains unclear about the influence of urban landscape pattern on soil fauna diversity. Aiming at solving the conflict between habitat loss and soil fauna diversity protection caused by urbanization, we summarized research progress on the impacts of urban landscape pattern on soil fauna biodiversity along urbanization gradient, to reveal the patterns of soil fauna distribution in different habitats in landscape scale. This review provides a new thought for the protection of urban soil fauna diversity and enriches the contents of landscape ecology.

Research advances on monitoring and toxicology of microplastic pollution in marine as indicated by bivalves.

2018, 37(7):  2205-2212. 

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As a new pollutant in marine, microplastic (plastic with the size less than 5 mm) can be ingested by marine biota with significant health effects. Along with more focus on the contamination chemistry and ecological toxicology of microplastic in marine, pollution monitoring and toxicological research based on the biological indicators have recently become a hot topic. Bivalves can serve as indicators of microplastic pollution in microplastic toxicological research because they have extensive filter-feeding activities and can expose directly to microplastic in marine. Here, we critically reviewed the methods of identifying microplastic in bivalves, the accumulation of microplastic ingested by bivalves of different areas, and their ecotoxicological effects on bivalves in laboratory experiments. In addition, we proposed future research directions, including the standardization of bio-monitoring protocols on microplastic pollution by bivalves as indicators and the research on subchronic toxicological effects of microplastic on bivalves under the realistic environmental concentrations.

Health assessment of aquatic ecosystem in Huai River Basin (Henan section) based on B-IBI.

LI Xiao-yan, YU Lu-ji, Lü Xiao-yan, XU Yan-hong, HAO Zi-yao

2018, 37(7):  2213-2220. 

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Based on the data collected from 67 zoobenthos sampling sites (13 reference sites and 54 impaired sites) in the Huai River Basin (Henan section) from April to May of 2015, we analyzed twenty candidate biological index values for distribution range, correlations and discriminability, and screened out total number of taxa, proportion of sensitive groups, biotic index, number of amphipods and mollusks, percentage of amphipods and mollusks, and percentage of dominant species to form a B-IBI index system for the Huai River Basin (Henan section). Methods of 3-score system, 4-score system, and ratio technique were separately used to uniformize dimensions of various parameters. We compared the accuracy of the three methods for their function in evaluation. Results showed that the health evaluation criteria established on the B-IBI values of all the sampling sites and dimensions of various parameters uniformized with the 4score system were superior to that based on the ratio method and 3score system. A health assessment standard of river ecosystem suitable for the Huai River Basin (Henan section) was established based on the calculated B-IBI value: >24, healthy; 18-24, sub-healthy; 12-18, fair; 6-12, poor; ≤6, extremely poor. 19.40% of the total 67 sampling sites were in healthy state, 26.87% in sub-healthy state, 32.84% in fair state, 10.45% in poor state, and 10.45% in extremely poor state. In Huai River Basin (Henan section), the B-IBI was significantly positively correlated with the redox potential, and negatively correlated with NH₄⁺-N. There was no significant correlationbetween the other water quality indicators and B-IBI. The correlation between B-IBI and water quality indices varied greatly among different rivers.

Improvement of regional-scale winter wheat growth modeling with sub-pixel information.

CHEN Huai-liang， LI Ying， TIAN Hong-wei， ZHANG Fang-min， LI Tong-xiao， GUO Qi-le

2018, 37(7):  2221-2228. 

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To find a solution to the mismatch between remote sensing observation at regional scale and crop modeling at local scale and to improve the accuracy of crop growth modeling, we simulated the growth of winter wheat in Hebi, Henan during 2013-2017 based on the WheatSM crop model integrated with retrieval of leaf area index (LAI) derived from remote sensing data. The remote sensing data included MODIS and Landsat 8 Operational Land Image (OLI) data. Research methods included the reconstruction of LAI process line during the winter wheat growth period, extraction of sub-pixel information, and Ensemble Kalman Filter. Results showed that LAI values after the reconstruction of MODIS LAI process line and extraction of sub-pixel information from pure pixels with winter wheat over 80% were close to the measured LAI with RMSE of 0.69 during two key growing seasons. Compared with actual regional yield during 2013 to 2017, RMSE was 6.73×10⁸ kg for simulation without any assimilation process, 8.24×10⁸ kg for simulation assimilating original LAI, and lowered to 3.48×10⁸ kg for simulation with assimilating MODIS LAI processed with process line reconstruction and sub-pixel information extraction. Our results suggested that the accuracy of crop model at regional scale can be improved when LAI process line is reconstructed and sub-pixel information is extracted to match the spatial scale of crop model.