Table of Content

10 August 2009, Volume 28 Issue 08

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Articles

Responses of specific leaf area of dominant tree species in Northeast China secondary forests to light intensity.

2009, 28(08):  1437-1442. 

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Aimed to understand the responses of the dominant tree species (Pinus koraiensis, Picea koraiensis, Juglans mandshurica, Fraxinus mandschurica, Phellodendron amurense) in the secondary forests of Northeast China to the variations of light intensity, their seedlings or saplings were grown under different light intensities (15%, 30%, 60%, and full irradiance), with their specific leaf area (SLA) measured. The SLA was species-dependent, and there was a significant difference between evergreen coniferous species and deciduous broadleaved species ( P <0.001), suggesting the different life strategies between the two functional groups. With the decrease of light intensity, the SLA of test tree species had an increasing trend, especially at 15% and 30% irradiance compared with at 60% and full irradiance ( P <0.05). There was a large inter-specific variability in the SLA flexibility with respect to light intensity. In addition, the light regimes where the largest variations of SLA occurred were distinctly different. The SLA of  P. koraiensis  with different ages exhibited the similar variation pattern with light, whereas higher flexibility was observed in relatively young seedlings (4 years old). It was suggested that all test tree species could adapt to the variations of light condition by changing their leaf morphology. At low light conditions, the seedlings would increase their light resource capture ability by enlarging leaf area per unit mass. However, species-dependent responses to light implied the differences in light acclimation mechanisms, which would be very important for the co-existing of different species in forest ecosystem. The greater responses of younger seedlings to light indicated the important role of the seedlings in the study of leaf level eco-physiological mechanism during plant regeneration.

Life history characteristics and spatial pattern of Quercus liaotungensis population in Dongling Mountain of Beijing, China.

2009, 28(08):  1443-1448. 

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To study the life history characteristics and spatial pattern of plant population is of theoretical and practical significances in analyzing the population’s succession dynamics, judging its distribution pattern, and predicting its evolution process and changing trend. In this paper, the life history characteristics of  Quercus liaotungensis population in Dongling Mountain of Beijing were analyzed from the aspects of static life table, age structure, and survival curve. In the study area, biotic factors were the most important factors affecting the viability of  Q. liaotungensis  population. The gradually decreased expected life value in static life table reflected the declining trend of the viability of the population. The individuals in each size class of the population showed a clustered distribution, and the coexistence of seedlings and stump-sprouts was the results of the adaptation to environmental stress and the co-evolution with the environment, which implied that the population had higher stability under natural conditions. Due to the strong stability and adaptability of  Q. liaotungensis population, the whole community would tend to have a progressive succession with the development of the population, and gradually approach to the climax community with stable structure and making best use of environmental resources.

Species abundance distribution pattern of forest communities on Loess Plateau.

2009, 28(08):  1449-1455. 

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By using species abundance statistical models (logarithmic series distribution model and lognormal distribution model) and niche models (broken stick model, overlapping niche model, and random assortment model), this paper studied the variations in the species abundance distribution pattern of three forest communities at different succession stages in Malan forest region of Ziwuling Mountain on the Loess Plateau. The study with species abundance statistical models showed that in the Betula platyphylla community of early succession stage, the species were rich but distributed unevenly; in the natural Pinus tabulaeformis community of middle succession stage, P. tabulaeformis was dominant, and the understory shrub and herb species were less and in centralized distribution; in the climax Quercus liaotungensis community, the species had a uniform and centralized distribution, and many gaps were formed by the standing dies. These three forest communities fitted the species abundance niche models well, indicating that in the process of succession, the species distribution was affected by many natural and anthropogenic factors, and it was unwise to only choose one niche model to study the species abundance of forest community.

Population structure and its dynamics of Abies fargesii in Qinling Mountains.

2009, 28(08):  1456-1461. 

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To explore the population structure and its dynamics of Abies fargesii in the Foping National Nature Reserve on the south-facing slope of the middle Qinling Mountains, an investigation was made on the age structure, life table, and survival curve of the populations at different altitudes. All the A. fargesii populations at different altitudes (2350 m, 2500 m, and 2700 m) displayed a declined pattern. The majority of the individuals were in the middle age class, while the individuals in young age class were fewer. The mortality (d_x), mortality rate (q_x), and disappearance rate (K_x) of the A. fargesii populations were in negative values, showing that young trees were very insufficient at each altitude. With increasing altitude, young age class individuals increased, while elder age class individuals decreased. The analysis on the life table and survival curve of the A. fargesii populations indicated that the age classes of the individuals with the maximum survival rate and the maximum mortality rate all decreased with decreasing altitude, and the distribution pattern of the A. fargesii populations changed from random at low and mid altitudes (2350 m and 2500 m) to clumped at high altitude (2700 m).

Effects of different forest fuel treatments on potential forest fire regimes in Great Xing′an Mountains: A simulation study.

2009, 28(08):  1462-1469. 

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Forest fire prevention policy has been implemented over 50 years in the Great Xing′an Mountains in Northeast China, which lengthened the mean forest fire return interval and increased the forest fuel load. It’s needed to incorporate forest fuel management with the current forest fire prevention policy. In this study, ten fuel treatment scenarios were designed, five of which were the prescribed burnings (PB02, PB04, PBP6, PB08, PB10) and the other five were the prescribed burnings plus mechanical removals (PR02, PR04, PRP6, PR08, PR10), taking no treatment (NoTreat) as a contrast. The long-term (300 years) effects of the forest fuel treatment scenarios on the total burned area, the area burned by various intensity fires, and the dynamic characteristics of fire intensity were analyzed by using a spatially explicit forest landscape model LANDIS, and the results showed that prescribed burning could reduce the total burned area, but had less effect on reducing the area burned by high intensity fires because the decrement of total burned area became lesser with the increase of treatment size. However, prescribed burning plus mechanical removal could dramatically reduce the total burned area while changing the high intensity fire (classes 4 and 5) to low intensity fire (classes 1 and 2). It was suggested that forest fuel treatment should be implemented for a long period to effectively reduce the forest fire intensity and the likelihood of catastrophic fires.

Phenophase change of typical herbaceous plants in Inner Mongolia in spring and its response to climate warming.

2009, 28(08):  1470-1475. 

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To understand the change patterns  and the relationships between climate and phenophase is of significance in instructing agricultural production and environmental monitoring. This paper analyzed the change trends of the phenophase of herbaceous plants in different areas of Inner Mongolia in spring 1982-2006, and of the air temperature at the prophase of the plants. The models for predicting the first flowering date of herbaceous plants in mid-west and east Inner Mongolia were established, and the future changes in the first flowering date in the scenario of climate warming were evaluated. Since the 1980s, the first flowering date was advanced, air temperature was increasing, and climate warming was more evident in spring than in winter. The change trends of the first flowering date and air temperature had obvious regional characters. In the mid-west area of Inner Mongolia, the advance in the first flowering date and the increase of air temperature were more evident than those in the east area. The first flowering date and the air temperature in spring varied evidently in the two areas, and the variation of the air temperature in winter was more evident in the mid-west area than in the east area. The first flowering date was negatively related to the prophase air temperature, and the main affecting factor was the air temperature in spring. If the air temperature raised 1.0 ℃ in the future, the first flowering date would advance 3.1 to 5.0 days.

Effects of simulated acid rain on photosynthetic physiology of Carya cathayensis and Myrica rubra.

2009, 28(08):  1476-1481. 

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Taking the typical subtropical economic tree species Carya cathayensis and  Myrica rubra in Zhejiang Province as test objects, a pot experiment was conducted to study the photosynthetic characteristics of their seedlings under effects of simulated acid rain with a gradient of pH 2.5, pH 4.0, and pH 5.6 (CK). In the maximum net photosynthetic rate ( A _max ), dark respiration rate ( R _d), light saturation point ( LSP ), and light compensate point ( LCP ) of  M. rubra  were obviously higher than those of  C. cathayensis under no acid rain condition. Under the effects of pH 4.0 acid rain, the A _max  and  LSP of  C. cathayensis  decreased significantly, and the apparent quantum efficiency ( AQE ) of  M. rubra  increased significantly; while under the stress of pH 2.5 acid rain, the A_max and AQE of  C. cathayensis  decreased significantly, and the LSP of M. rubra increased significantly. The effects of acid rain on  C. cathayensis were greater in summer than in spring, and those on  M. rubra  were greater in spring than in summer and autumn.

Effects of different tending measures on carbon density, storage, and allocation pattern of Phyllostachy edulis forests in western Fujian Province.

2009, 28(08):  1482-1488. 

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Carbon density, storage, and distribution pattern of Phyllostachy edulis  forests in Yongan County, Fujian Province were studied under three tending measures including types Ⅰ (digging shoots, weeding, fertilizing and irrigating), Ⅱ (digging shoots, weeding and fertilizing) and Ⅲ (digging shoots and weeding). The carbon density of different bamboo organs varied from 0.3947 to 0.5619 g·g^-1 , and was in the order of rhizome > stem > branch > culm stump > leaf > root > rhizome root. The bamboos of different ages had significant differences in the carbon densities of stem, branch, leaf, and root ( P <0.01), but no significant differences in the carbon density of culm stump ( P >0.1). The average carbon density of 1-6 years old  P. edulis was 0.4579-0.4957 g·g^.-1 , and there was a decreasing trend with increasing age. Under the  management typesⅠ, Ⅱ, and Ⅲ, the total carbon storage of the forest was 227.37, 261.66 and 288.47 t·hm^-2 , and the carbon storage of bamboo layer, litter layer, and soil layer was 76.74, 64.30, and 55.91 t·hm^-2 , 2.59, 3.01, and 4.88 t·hm^-2 , and 150.64, 197.36, and 232.56 t·hm^-2 , respectively. In the total carbon storage of the forest, bamboo layer occupied 32.61% in type Ⅰ, 23.43% in type Ⅱ and 17.69% in type Ⅲ, litter layer occupied 1.14% in type Ⅰ, 1.15% in type Ⅱ and 169% in type Ⅲ, and soil layer occupied 6625% in type Ⅰ, 75.43% in type Ⅱ and 80.62% in type Ⅲ. The annual carbon fixation was in the order of type Ⅰ > type Ⅱ > type Ⅲ, and was the highest (56.47%-59.66% of the total) in bamboo stem and the lowest (2.52%-2.83%) in rhizome root.

Germplasm resource investigation of wild freshwater fish in Beijiang River of Guangdong.

2009, 28(08):  1489-1493. 

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In order to understand the germplasm resources and genetic diversity of wild freshwater fish in Beijiang River of Guangdong Province; an investigation was made in 2007-2008. Thirty-two species of wild freshwater fish were collected; belonging to three orders; ten families; and twenty-seven genera; among which; there were twenty-one species of Cypriniformes; four species of Perciformes; and seven species of Siluriformes. Of the twenty-one species of Cypriniformes; there were twelve species belonging to Cobitidae; Homalopteridae; Gastromyzonidae; and Balitoridae. The mtDNA D-loop sequences of test freshwater fish were determined; and submitted to GenBank (Accession numbers EU380208-EU380236 and EU697088-EU697148). Molecular phylogenetic trees were constructed by using the maximum parsimony method. All the results showed that Beijiang River had abundant freshwater fish resource; and mtDNA D-loop could be a good molecular marker for the fish species identification.

Effects of water temperature, salinity, pH, and anaesthetics on oxygen consumption rate of juvenile Siganus canaliculatus .

2009, 28(08):  1494-1498. 

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By using Winkler′s method, this paper studied the variation patterns of the oxygen consumption rate of juvenile Siganus canaliculatus  (body mass (0.706±0.155) g, body length (3.325±0.205) cm) under effects of different water temperature, salinity, pH, and anaesthetics. The oxygen consumption rate of juvenile S. canaliculatus  was increased with the increase of water temperature and the decrease of water salinity, and the regressive correlations could be represented by logarithmic equation Y = 1.3819 ln X -3.55 ( r =0.9475,  P <0.01) and linear equation Y =-0.1802 X +1.7551  (r =0.9837,  P <0.01), respectively. The optimum temperature for the juvenile′s growth was from 24 ℃ to 32 ℃. Water pH also had significant effects (P<0.01) on the oxygen consumption rate which was the lowest at pH 6.0 and the highest at pH 9.0. The oxygen consumption rate decreased with increasing concentration of eugenol and MS-222, and was significantly lower in experimental groups than in control group. Eugenol and MS-222 could be used as the anaesthetics for the long distance transportation of juvenile  S. canaliculatus .

Effects of different additives on cherry volley duck growth performance and duck house mephitis concentration.

2009, 28(08):  1499-1504. 

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1600 one-day-old cherry volley ducks were randomly allocated to 8 groups and fed with different proportions and combinations of antibiotic, zeolite, Chinese herbal medicine, effective microorganisms (EM), and amino acid-trace mineral chelates, aimed to approach the effects of different additives on the duck growth performance and duck house mephitis concentration. After fed with zeolite, EM, or Chinese herbal medicine, the daily gain and feed efficiency of the ducks increased ( P <0.05) significantly. In the first 14 days, treatment zeolite + EM had the best effects on the increase of duck live weight, feed intake, and daily gain, and treatments antibiotic and antibiotic + zeolite increased the feed efficiency significantly ( P <0.05). In the late 21 days, zeolite, EM, and Chinese herbal medicine increased the feed efficiency, and zeolite + Chinese herbal medicine as well as amino acidtrace mineral chelates increased the feed intake, daily gain, and mass quality significantly ( P <0.05). Zeolite, EM, and Chinese herbal medicine decreased theNH_3,H₂S and CO₂ concentrations in the duck house, and zeolite, amino acid-trace mineral chelates, and zeolite + Chinese herbal medicine had the best effects in reducing thetheNH_3,H₂S and CO₂ concentrations, respectively. It was suggested that zeolite, Chinese herbal medicine, and EM could be the effective feed additives in improving the growth performance of cherry volley ducks and the available deodorizers in reducing the mephitis concentration in duck house.

Phenotypic flexibility of Calidris tenuirostris body structure during springtime stopover.

2009, 28(08):  1505-1509. 

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Through the description and analysis of the body-and organ phenotypes of  Calidris tenuirostris  at its stopover in Shanghai during spring migration, this paper studied the changes in the phenotypic flexibility of the body structure of the bird. During springtime stopover, the body mass of  C. tenuirostris increased significantly, with the maximum increment being about 52.2% of the mean body mass. This increase was mainly of fat mass increase, followed by pectoral muscle mass increase. There was a linear correlation between pectoral muscle mass and body mass. Leg muscle mass and heart mass also had an increasing trend with the increase of body mass. The changes in digestive organs manifested in two aspects,  i.e ., the mass increase of digestive glands (liver and pancreas) and the less change in digestive tracts (gizzard and intestine), which would promote the foraging efficiency rapidly and save the energy and time for restoration to maximize the migration speed, and benefit to the reservation of definite spare space for digestion. The other organs including brain, lung, kidney, spleen, eyes, and salt glands were in homeostatic during stopover.

Effects of nonylphenol on Rana nigromaculata  nerve action.

2009, 28(08):  1510-1514. 

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Electrophysiological methods were adopted to study the effects of different concentration nonylphenol (NP) on the impulse generation and conduction of sciatic nerve stem in  Rana nigromaculata . After treated with different concentration NP for 7 days, the activity and cutis characteristics of  R. nigromaculata were examined, and the performance parameters of sciatic nerve stem, including impulse conduction velocity, action’s potential peak value, and relative and absolute refractory periods, were measured with biological signal recording and processing system. Increasing NP dosage weakened the R. nigromaculata activity, and produced more blood spots on cutis, suggesting that NP could induce the abnormality of  R. nigromaculata activity, energy, and cutis. When the NP concentration increased, the impulse conduction velocity of sciatic nerve stem gradually slowed down, the peak value of action’s potential decreased, and the relative and absolute refractory period extended, which implied that there was a NP dosage-effect relationship. NP could decrease the sensitivity of  R. nigromaculata  sciatic nerve, and inhibit its impulse generation and conduction. No significant difference was observed in the nerve action between the control and the treatment 50 mg NP·kg^-1 , suggesting that  R. nigromaculata  had definite tolerance against lower concentration NP.

Roles of organic management in restoration of arthropod community diversity in citrus orchard.

2009, 28(08):  1515-1519. 

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A comparative study was conducted on the arthropod community diversity in the Citrus sinensis orchards under organic, conventional, and natural managements. After the conversion from conventional to organic management, the arthropods in the orchard increased 1 order, 24 families, and 130 species, and the individuals of pests decreased while those of natural enemies increased. The fluctuation ranges of the diversity index, evenness, and dominant concentration index of arthropod community in organic orchard within a year were between those in conventional and natural orchards. The species richness, diversity index, evenness, and dominant concentration index of arthropod community in organic orchard had no significant differences with those in natural orchard, but differed significantly with those in conventional orchard. Organic management could improve and restore the diversity of arthropod community in citrus orchard, and further, contribute to the ecological control of citrus pests.

Effects of water salinity on energy budget of Haliotis diversicolor  aquatilis.

2009, 28(08):  1520-1524. 

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By using  Laminaria japonica  as the diet, a feeding and growth experiment was conducted to study the energy budget of  Haliotis diversicolor aquatilis (initial body weight 25.96±0.13 g) at  salinity 21, 25, 29, 33, 37, and 41. The consumption energy, feces energy, excretion energy, mucus energy, metabolism energy, shell energy, soft tissue growth energy, proportions of these components to consumption energy, total growth efficiency (K₁), and net growth efficiency (K₂) of test abalones were determined, with the equations of energy budgets established. The proportions of the consumption energy allocated to the feces, excretion, mucus, and metabolism at salinity 21 were significantly higher than those at the salinity 25, 29, 33, 37, and 41 ( P<0.05). The proportion of the consumption energy allocated to soft tissue growth, the total growth efficiency (K₁), and the net growth efficiency (K₂) were the greatest at salinity 37 and the smallest at salinity 21, being significantly different with those at other salinities, while no significant differences were observed between salinity 25, 29, 33 and 41 ( P >0.05). From the viewpoints of feeding, metabolism, and growth, the appropriate  salinity for  H. diversicolor  aquatilis was 25-37.

Protozoa communities in moss crust in gold mine area of southwest Guizhou and their relations with nvironmental factors.

2009, 28(08):  1525-1530. 

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By using community diversity index and redundancy analysis (RDA), the protozoa communities in the moss crust in Laowangchang gold mine area of southwest Guizhou and their relations with environmental factors were studied. A total of 49 species belonging to 35 genera and 28 families were identified, most of which had low abundance. The variations of the protozoa communities were affected by various kinds of environmental factors, among which, heavy metals pollution and pH were the dominant factors ( P <0.01). The species richness and abundance of the protozoa communities declined with the aggravation of heavy metals pollution, and the effects of chemical factors were more obvious than those of physical factors.

Effects of Cistanche deserticola  parasitization on Haloxylon ammodendron  seedlings protective enzyme activities and osmotic adjustment substance contents.

2009, 28(08):  1531-1536. 

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In order to understand the effects of  Cistanche deserticola  parasitization on  Haloxylon ammodendron growth, the activities of protective enzymes (SOD, POD and CAT) and the contents of osmotic adjustment substances (soluble protein, soluble sugar and free proline) in  H. ammodendron assimilating branches were measured, and the comprehensive drought-resistant capability of  H. ammodendron  under parasitized and un-parasitized conditions was evaluated by subordinate function values analysis. During the whole measurement period (from June to September), the test enzyme activities in  H. ammodendron  assimilating branches all decreased after an initial increase, and were lower in parasitized than in un-parasitized  H. ammodendron  in early period. After parasitized by  C. deserticola , the MDA content in  H. ammodendron increased significantly, soluble protein and free proline contents increased in different degrees, while soluble sugar content decreased. The parasitization of  C. deserticola  gave the host plant a stress environment, making an obvious damage on host’s protective enzyme system and osmotic adjustment system and the decrease of host’s drought resistance.

Soil enzyme activities and their relations with soil fertility in a tea plantation under straw mulching and white clover intercropping.

2009, 28(08):  1537-1543. 

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A field plot experiment was conducted to study the changes in the soil catalase, urease, invertase, and acid phosphatase activities as well as the relationships between these enzyme activities and soil nutrient contents in a tea plantation under straw mulching and white clover intercropping. Mulching and intercropping increased the contents of soil organic matter, total N, and available N and P significantly, and intercropping increased soil catalase and invertase activities while mulching increased soil phosphatase and urease activities obviously. Soil catalase, urease, invertase, and phosphatase activities all had significant positive correlations with the contents of soil organic matter, total N, and available N. Path component analysis indicated that the test enzyme activities were most directly related to soil organic matter or total N content, and principal component analysis showed that the weight of soil catalase, urease, invertase, and acid phosphatase activities in the first main component was 0.842, 0.937, 0.873, and 0.847, respectively. It was suggested that soil catalase, urease, invertase, and acid phosphatase activities could be used to evaluate the soil C and N fertility in hilly tea plantations.

Distribution characteristics of microbial biomass carbon and dissolved organic carbon in Deyeuxia angustifolia marsh soils.

2009, 28(08):  1544-1549. 

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An in situ field investigation was conducted to study the distribution characteristics and related affecting factors of microbial biomass carbon (MBC) and dissolved organic carbon (DOC) in two types of  Deyeuxia angustifolia marsh soils in Sanjiang Plain. In D. angustifolia  wet meadow and  D. angustifolia  marsh meadow, the soil MBC and DOC contents in May-September were averagely 769.2 and 312.3 mg·kg^-1, and 2447.3 and 404.4 mg·kg ^-1 , and the proportions of soil MBC and DOC to soil total organic carbon were 2.50% and 1.03%, and 3.53% and 0.59%, respectively. Both the soil MBC and the soil DOC had the characteristics of obvious seasonal change, and their contents decreased with soil depth. Organic matter input, humus content, and water condition were the main factors affecting the distribution of soil MBC and DOC in  D. angustifolia  marsh soils.

Effects of low molecular weight organic acids on P accumulation in soybean ( Glycine max  L.) and inorganic P form transformation in soil.

2009, 28(08):  1550-1554. 

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A pot experiment with black soil was conducted to study the effects of low molecular weight organic acids (LMWOAs) citric acid, oxalic acid, malic acid, and their mixture on the P accumulation in soybean ( Glycine max  L.) and the inorganic P form transformation in soil. LMWOAs promoted the P adsorption and accumulation in soybean plants, but the effect differed with growth stage. Applying LMWOAs decreased the contents of soil total inorganic P and unavailable P (Ca₁₀-P, Fe-P, Al-P, and O-P), but increased the contents of soil available P (Ca₂-P and Ca₈-P), suggesting that LMWOAs promoted the transformation of soil unavailable P to available P. The effect of test LMWOAs was in the order of citric acid > oxalic acid > mixed acid > malic acid. Moreover, the exudates from soybean roots also promoted the transformation of soil unavailable P to available P, resulting in the decrease of soil total inorganic P and its fractions except Ca₂-P. The contribution of soil inorganic P fractions to the P uptake by soybean was O-P > Fe-P > Ca₁₀-P> Al-P > Ca₈-P >Ca₂-P.

Comprehensive agricultural drought-resistant capability of Henan Province: Analysis and regionalization.

2009, 28(08):  1555-1560. 

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Drought is the most important agricultural meteorological disaster in Henan Province. Based on the relevant data of agriculture, water conservancy, and soil since the 1990s, an index system was built for the evaluation of the comprehensive agricultural drought-resistant capability of the Province, and a comprehensive index was used for the regionalization of the capability. The ratio of irrigated area to cultivated area, the number of electromechanical wells per each effective irrigational unit, the coefficient of soil available retaining water, and the coefficient of agricultural machine’s power were the available indices for the evaluation of the comprehensive capability of agricultural drought-resistance. According to these indices, the comprehensive capability of agricultural drought-resistance in the whole area of Henan was classified into three classes, i.e., high, moderate, and low. The high capability region included most middle and north areas of Henan; moderate capability region distributed more scattered, including low hilly regions in west and middle Henan, east region of Pingdingshan, southwest region of Zhumadian and Xinyang, the region from east Kaifeng to Shangqiu, and most regions of Linzhou and Huixian; while low capability region could be further classified into two sub-regions, one included Sanmenxia and the west and middle Luoyang and Nanyang, and the other included the east and middle Xinyang.

Effects of different rootstocks on chilling-tolerance of grafted watermelon seedlings.

2009, 28(08):  1561-1566. 

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With the watermelon ( Citrullus vulgarris ) Zhengkang No.1 as the scion and  C. moschata, C. ficifolia , and  Lagenaria siceraia as the rootstocks, this paper studied the chilling-tolerance of grafted and self-rooted watermelon seedlings under (7.5±0.5) ℃ stress. Under this low temperature stress, the malondialdehyde (MDA) content and electrolyte effusive rate of grafted watermelon seedlings were significantly lower, while their chlorophyll, proline (Pro) and soluble sugar contents and superoxid dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were significantly higher, compared with those of self-rooted watermelon seedlings. On the twelfth day after low temperature treatment, the total chlorophyll content in the leaves of  C. moschata -Zhengkang No.1,  C. ficifolia-Zhengkang No.1, and  L. siceraia-Zhengkang No.1 decreased by 30.48%, 28.48% and 52.69%, respectively. The MDA content of  L. siceraia-Zhengkang No.1 changed obviously, with an increase of 313.16% from 0 to 6 days, and the relative electrolyte effusive rate was significantly higher than that of the other two grafted groups. Under the low temperature treatment, the soluble sugar content of  C. moschata-Zhengkang No.1 was 24.71% and 31.17% higher than that of  C. ficifolia-Zhengkang No.1 and  L. siceraia-Zhengkang No.1, respectively, and the SOD, POD and CAT activities of  C. moschata-Zhengkang No.1 were significantly higher than those of the two latter grafted groups. The survival rate of  C. moschata-Zhengkang No.1,  C. ficifolia-Zhengkang No.1,  L. siceraia-Zhengkang No.1, and Zhengkang No.1 was 84;29%, 79;%, 65;59%, and 45;12%, respectively. It was suggested that the chilling-tolerance of watermelon seedlings could be improved via grafting with suitable rootstocks.  C. moschata-Zhengkang No.1 had the best chilling-tolerance, followed by  C. ficifolia-Zhengkang No.1, and L. siceraia-Zhengkang No.1.

Effects of controlled traffic tillage on soil physical properties.

2009, 28(08):  1567-1571. 

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A field experiment was conducted in Zhangye of Gansu Province China， to examine the effects of controlled traffic tillage on the soil bulk density, soil moisture content, and soil strength. It was found that after harvest, soil bulk density decreased in the order of traffic lanes > crop zone of conventional cultivation > crop zone of controlled traffic tillage. Controlled traffic tillage increased the bulk density of 0-20 cm soil layer in traffic lanes significantly, but mitigated the impacts of machine work in crop zones. Comparing with that before sowing, the soil bulk density after crop harvest increased significantly in the crop zone of conventional cultivation, but had no significant change in the crop zone of controlled traffic tillage. After irrigation, the decrease of soil moisture content in traffic lanes was obviously lagged, compared with that in crop zone of conventional cultivation, suggesting that the soil compaction in traffic lanes increased soil water-holding capacity and decreased soil water evaporation. The soil strength in 0-20 cm layer was higher in traffic lanes than in the crop zone of conventional cultivation, but that below 20 cm layer had no obvious difference. It was concluded that controlled traffic tillage had the advantages of mitigating the impacts of machine work and irrigation on crop zones, while the impermeable soil layer formed by the machine work in traffic lines could decrease the soil water evaporation from un-cropped zones.

Soil respiration characteristics of typical urban lawns in Shanghai.

2009, 28(08):  1572-1578. 

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By using CFX-2 Soil Respiration Chamber, the soil respiration characteristics of four typical urban lawns ( Cynodon dactylon × C. transadlensis , mixture lawn with  Lolium perenne  and C. dactylon × C. transadlensis, Zoysia japonica , and  C. dactylon ) in Shanghai were studied. An obvious seasonal change was observed in the soil respiration rate, with the maximum in July-August and the minimum in December-next January. The average soil respiration rate of the lawns was in the order of  C. dactylon×C. transadlensis <mixture lawn with  L. perenne  and  C. dactylon<Z. japonica<L. perenne , being 0.13-2.25, 1.16-5.95, 0.93-8.27, and 1.21-9.27  μmol·m^-2·s^-1, respectively. The soil respiration rate had a significant exponential correlation with air temperature and with the soil temperature at depths 5 cm and 10 cm. The diurnal patterns of the soil respiration rate of  C. dactylon×C. transa dlensis and of mixture lawn with  L. perenne and  C. dactylon×C. transa dlensis could be expressed as one-humped curve, and the variation trends were similar to those of air temperature and the soil temperature at depths 5 cm and 10 cm. The sensitivity of the four lawns soil respiration to temperature (Q₁₀value) was from 1.60 to 2.66. For the lawns except Z. japonica, no significant relationship was found between soil respiration rate and soil moisture content. The soil respiration characteristics of the lawns had a close relationship to the growth habit of grass. TheQ₁₀ value of the mixture lawn with cold-warm-season turf grass was relatively smaller, which would be beneficial to the improvement of urban ecological landscape and environmental quality.

Growth responses and cadmium accumulation of Lonicera japonica under cadmium stress.

2009, 28(08):  1579-1583. 

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A hydroponic experiment was conducted to study the growth responses and cadmium (Cd) accumulation characteristics of  Lonicera japonica  under stress of different concentration Cd. Cd had less impact on the growth of  L. japonica , and even, low concentration (5 and 10 mg·L ^-1) Cd could increase the stem height and leaf chlorophyll content. When the Cd concentration was up to 50 mg·L ^-1, the stem height and root length had somewhat decrease but less difference with the control. The index of tolerance (IT) was above 0.8, indicating that L. japonica had stronger tolerance to Cd. When the Cd concentration was 25 mg·L ^-1, the shoot Cd content reached 28612 μg·g ^-1 , and the bioaccumulation factor (BF) was above 1, suggesting that  L. japonica  possessed the characteristics of Cd-hyperaccumulator and had great potentiality in the phytoremediation of Cd-contaminated soil.

Metal ions removal from acid mine drainage by using hydrothermally modified fly ash.

2009, 28(08):  1584-1588. 

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Acid mine drainage (AMD) is an important environmental problem associated with both working and abandoned mining operations. By using low cost fly ash as raw material, a hydrothermally modified fly ash-zeolite sorbent was prepared, and the efficiency of this sorbent in removing metal ions from AMD was studied under conditions of different pH, sorbent dosage, and contact time. At pH 7, the removal rate of Pb²⁺, Zn²⁺, and Cu²⁺was 100%, 95.2%, and 95.8%, respectively. The Cu²⁺ removal was mainly under the actions of both adsorption and precipitation, while the removal of Zn²⁺ and Pb²⁺was mainly due to adsorption. The adsorption rate of Pb²⁺, Zn²⁺and Cu²⁺increased with increasing sorbent dosage, and the optimal dosage for the removal of Pb²⁺, Zn²⁺ and Cu²⁺was 20, 25, and 35 g·L ^-1  , respectively. When the contact time was 20, 40, and 45 min for Pb²⁺, Zn²⁺, and Cu²⁺, the removal rate of these metal ions was up to 94.2%, 95.2%, and 98.2% respectively. The co-existence of the three ions didn't promote but restrain their removal.

Environmental effects of mercury in coal mine spoils in Panxian of Guizhou Province.

2009, 28(08):  1589-1593. 

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By using cold vapor atomic fluorescence technique, the mercury (Hg) contents in the original and weathered coal mine spoils in Panxian of Guizhou Province, and in the plants growing on the soils from the weathered coal mine spoils were measured, aimed to reveal the distribution patterns of Hg in the spoils and the environmental effects of the Hg in study area. The total Hg content in the original coal mine spoils was averagely （0.137±0.076） μg·g^-1, with no abnormal enrichment, and that in weathered coal mine spoils was averagely （0.154±0.056） μg·g^-1, without any changes with weathering degree. The total Hg content in the weathered coal mine spoils was slightly higher than that in the background soils. In the soils from weathered coal mine spoils with spontaneous combustion and in the deeper soil layers affected by leaching, Hg had an abnormal enrichment, with its total content reached to （1.627±0.294） μg·g^-1. The soils from weathered coal mine spoils, especially from those with spontaneous combustion, had high levels of available Hg, and thus, the Hg content of some plants growing on these soils exceeded the national standard.

Heat island effect in Changzhou City based on remote sensing information.

2009, 28(08):  1594-1599. 

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To study the heat island effect in urban area of Changzhou City, a land surface temperature (LST) image was established by using mono-window algorithm to interpret the 6th band of Landsat TM. On September 18th 2006, the day the Landsat TM passed through Changzhou, the heat island intensity of the mean LST in Changzhou urban area was 3.81 K. The spatial distribution pattern of heat island effect in Changzhou could be described as a one piece area in addition to several decentralized associated groups, being consistent with the current urban development pattern, which suggested that the land use/cover change and anthropogenic heat emission induced by urbanization would be considered responsible for the formation of heat island effect. The mean LST of industrial land was significantly higher than that of non-industrial land, which indicated that the anthropogenic heat produced by industrial production had evident effects on the formation of heat island effect and the increase of heat island intensity.

Relationships between diffuse radiation and cloud in Changbai Mountain.

2009, 28(08):  1600-1606. 

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Based on the measurements of solar radiation and cloud amount in Changbai Mountain in 1982-2001, the diurnal, seasonal, and inter-annual variations of diffuse radiation and diffuse fraction as well as their relationships with cloud amount, cloud type, and solar elevation were analyzed. The diffuse radiation had the characteristics of being the strongest at noon in diurnal course and in July in seasonal course, and showed a decreasing trend from 1982 to 2001. The diffuse fraction was the minimal at noon in diurnal course and the maximal in July in seasonal course, and fluctuated between 0.38 and 0.55 in inter-annual course. Both the diffuse radiation and the diffuse fraction increased with the increase of the high or low cloud amount. The mean daily diffuse radiation and diffuse fraction were linearly positively correlated with the mean daily total or low cloud amount, and the correlation with total cloud amount was closer than that with low cloud amount. Altocumulus had the maximal diffuse radiation and diffuse fraction, followed by Cirrus, Cumulonimbus and Cumulus, and clear sky. The diffuse radiation increased while the diffuse fraction decreased along with solar elevation, fitting quadratic function.

Analysis of human body comfort index of 20 tourist cities in China.

2009, 28(08):  1607-1612. 

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By using the observation data of mean daily air temperature and relative humidity from 1951 to 2007, the daily body comfort index of 20 main tourist cities in China in the 57 years was calculated. Based on this calculation, the comfort grades and comfortable months of the cities were formulated. From north to south, the main tourist cities in China had a time distribution of comfortable months gradually changed from May-September to before May or after August/September, and the comfortable days showed an increasing trend. Along the Yangtze River, the comfortable months of main tourist cities were mainly April, May, and October, and the comfortable days were the most in the upper reaches, followed by in lower reaches, and middle reaches. From low to high altitudes, the time distribution of comfortable months tended to be in June and July, and the comfortable days showed a decreasing trend. Under the similar latitudinal conditions, the comfortable months and days were more in coastal tourist cities than in inland tourist cities. These results could provide scientific basis for the comprehensive exploitation of the advantages of China’s tourism climate resource, the reasonable arrangement of optimal travel time and places for tourists and travel agencies, and the development of tourism meteorological services for relevant departments.

Landscape patterns of rocky desertification in homogenous dolomite catchments in Guizhou Province.

2009, 28(08):  1613-1618. 

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Three homogenous dolomite catchments with different landforms in Guizhou Province were selected to analyze the landscape pattern of rocky desertification. The rocky desertification was most severe in slope areas where the landscape diversity index and landscape evenness index were the highest, followed by in valley areas. The landscape shape index and landscape fragmentation index were the highest in valley areas, followed by in plateau areas, and the landscape contagion index decreased gradually from plateau to valley areas. Slope areas had the largest area and the highest intensity of rocky desertification, and their landscape was instable; valley areas had larger area of moderate rocky desertification, and natural factors dominated the development of their landscape; while plateau areas had stable landscape, and its ecological environment was the best.

Landscape changes of Wuhan wetlands in 1978-2007 with the process of urbanization.

2009, 28(08):  1619-1623. 

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By using the multi-temporal Landsat TM (or MSS) images in 1978-2007 as the basic data, this paper analyzed the landscape changes of Wuhan wetlands under the background of urbanization in recent 30 years. In the study period, the wetland area in Wuhan was decreasing, with a mean annual decreasing rate of 0.89% and a mean annual decrement of 1655.79 hm². In 1991-2002, the annual decreasing rate of wetland landscape was higher than the mean decreasing rate in recent 30 years, and was synchronous with the area increase of Wuhan built-up area. During the study period, the area of natural wetland decreased, while that of constructed wetland increased. As a major type of Wuhan wetland, the lake wetland had the fastest decline in area, being a direct cause of wetland area decrease in Wuhan. The increasing area of constructed wetland did not change the decreasing trend of total wetland area. With rapid urbanization, the wetlands in Wuhan showed the trends of patch density and fragmentation increased and fractal and connectivity decreased. Though the implementation of related protection laws kept the rate of wetland shrinking within limits, the decreasing trend of wetland area in Wuhan did not have any change. Therefore, the protection and planning of Wuhan wetlands, especially the river and lake wetlands should be further strengthened.

PBPK model-based DDTs-HCHs mixed health risk in Lake Taihu region.

2009, 28(08):  1624-1629. 

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Based on the investigation of residents DDTsHCHs mixed exposure via different ways in Taihu Lake region, a physiologically based pharmacokinetic (PBPK) model was built to analyze the distribution and accumulation processes of the pesticides in human tissues, and a tissue dose hazard index was used to assess the health risk of the mixed exposure. For the male and female residents, their health risk index was 0.147-2.499 and 0.138-2.223, and the probability of exceeding the acceptable risk was 24.6% and 16.5%, respectively. Comparing with the traditional mixed health risk assessment method,  i.e ., HI method, the PBPKbased tissue dose hazard index (HI _tissue-dose ) could better reflect the development trend of mixed health risk.

Interactions between terrestrial ecosystem water and carbon cycles and their simulation methods: A review.

2009, 28(08):  1630-1639. 

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This paper reviewed the researches on the interactions between water and carbon cycles in terrestrial ecosystems, and the algorithms developed to simulate these cycles and their interactions. Future research efforts to be taken were also suggested. Carbon and water cycles are the coupled ecological processes in terrestrial ecosystems. They themselves and their interactions are affected by climate, atmospheric composition, and human activities, and impose significant feedbacks on climate system, being the research focuses in global change study. Many observational and modeling studies have been conducted to study the interactions of the two cycles at various spatial and temporal scales as well as their responses to the changes in environmental factors and land cover. Soil water markedly affects the main components of the carbon cycle (photosynthesis and respiration), but the affecting strength varies with the types of ecosystems. To accurately simulate soil water dynamics and its roles in the carbon cycle is the basis of reliable simulation of terrestrial carbon budget. Efforts should be taken to implement coupled modeling of carbon and water cycles in ecological and hydrological models. Most of current models ignore the effects of topography on the horizontal redistribution of soil water, and utilize empirical methods to simulate the effects of soil water on heterotrophic respiration, which limit the reliability of carbon budget estimation and needs to be resolved.

Forage grass in phytoremediation of heavy metals-contaminated soils: A review.

2009, 28(08):  1640-1646. 

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This paper summarized the harms of soil heavy metals pollution, the advantages of  using forage grass as remediation plant, and the effects of main forage grass species in phytoremediation of heavy metals-contaminated soils. To select the forage grass species with strong capability in accumulating heavy metals and to search for various kinds of measures to raise the phytoremediation capability of forage grasses would be the research hotspots, and the post-processing of phytoremediation, especially the production techniques of recycling the heavy metals from plants, should be more concerned with.

Environmental behavior of BTEX in soil: A review.

2009, 28(08):  1647-1654. 

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BTEX is a general designation of benzene, toluene, ethylbenzene and xylene, which has been received wide attention because of its high biological toxicity. To investigate its environmental behavior in soil would help to understand its environmental fate and to evaluate its risks to ecosystems and human health. This paper summarized the environmental behavior of BTEX in soil from the aspects of adsorption-desorption, volatilization, eluviation, and degradation, with the focus on the factors affecting the adsorption and desorption of BTEX in soil. The future research directions were also discussed.

Water use efficiency of terrestrial plants: A review.

2009, 28(08):  1655-1663. 

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Plant water use efficiency (WUE) is a key eco-physiological index reflecting the coupling relationship between carbon and water cycles of vegetation ecosystems. In the meanwhile, the variability of WUE can reflect the responses of terrestrial plants to global change. With the development and application of stable isotope technique and eddy covariance technology, the concepts and measurement methods of WUE are improved, and the research scales about WUE are extended. To further understand the variation characteristics and regulation mechanisms of WUE would help to reveal the plant eco-physiological adaptation mechanism in different habitats, and promote the understanding of the coupling relationship between the carbon and water cycles of terrestrial ecosystems. At present, the research on ecosystem WUE is still in its initial stage, and how to correlate the WUE on different scale levels will be an important research field in the future. In this paper, the affecting factors of leaf WUE, the interspecific differences in plant WUE, the relationships between WUE and leaf characters, and the research progress on WUE at ecosystem scale are reviewed, and the future research aspects are proposed.

Food composition of wintering long-eared owls ( Asio otus ) in different habitats in Beijing.

2009, 28(08):  1664-1667. 

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To understand the spatiotemporal variations of the food composition of wintering  Asio otus  in the urban and suburban areas of Beijing, the diets were collected monthly in the wintertime 2003-2006, with their composition analyzed. Among the three main preys in the urban and suburban areas of Beijing, bats occupied 41.6% and 43.0%, rodents occupied 27.5% and 39.4%, and birds occupied 30.7% and 18.9%, respectively. There were significant differences in the prey composition of A. otus  between the urban and suburban areas in the wintertime 2004-2005 and 2005-2006, and between early winter and late winter. In the same areas, the prey composition also showed significant differences among years and among wintering periods. It was suggested that the difference in the predation rates of prey species by the wintering A. otus   was related to the availability of prey resources in the habitats.

Ecological corridor construction based on target species protection: A case study of Chongming Island.

2009, 28(08):  1668-1672. 

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Landscape fragmentation and habitat loss are widely recognized as the major threats to the biodiversity decrease and species extinction. In order to widen wildlife’s living area, ecological corridors have been built between fragmented habitats, which can not only stimulate gene exchange, but also improve species viability in fragmented habitats. Chongming Island, as an isolated deposition sand island of Shanghai, is significantly threatened by the decrease and fragmentation of forest patches. As a result, a great number of terrestrial animals whose living depends on forest habitats are tended to be extinct. In this paper, we chose hedgehog ( Erinaceus europaeus ), the first class protected animal, as the target species. Based on the analysis of its living behavior and matrix’s spatial distribution, this paper adopted the least-cost model and Geographic Information System (GIS) to help finding the best corridor between the living habitats of  E. europaeus . It was found that this method could provide a scientific basis for the ecological corridors’ planning and construction with the purpose of terrestrial wild animal conservation.