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不同光照和水分条件对土著灾变种金钟藤形态性状和化感作用的影响

黄乔乔1,沈奕德1,李晓霞1,张国良2,黄东东1,范志伟1**   

  1. (1中国热带农业科学院环境与植物保护研究所, 海口 571101; 2中国农业科学院农业环境与可持续发展研究所,
    北京 100081)
  • 出版日期:2015-02-07 发布日期:2015-02-07

Effects of light and water availability on the morphology and allelopathy of the native outbreak species Merremia boisiana (Gagnep.) Oostr.

HUANG Qiao-qiao1, SHEN Yi-de1, LI Xiao-xia1, ZHANG Guo-liang2, HUANG Dong-dong1, FAN Zhi-wei1**   

  1. (1Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China;  2 Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China)
  • Online:2015-02-07 Published:2015-02-07

摘要:

金钟藤为海南原产,近20年来种群数量迅速增多,并对许多次生林、人工林和灌木林造成严重危害。金钟藤种群成灾的生境或区域有不同的光照和水分条件,而灾变种往往通过较高的表型可塑性来适应多样的生境条件。为揭示土著灾变种金钟藤适应多样生境条件的生理生态机制,本文通过温室盆栽试验研究了不同光照和水分条件对金钟藤生长、形态性状及其可塑性、化感作用的影响。结果表明,高光干旱条件下金钟藤生物量有所降低。在低光下,金钟藤增加了茎总长度、比茎长、比叶面积,降低了根冠比。这些形态性状的表型可塑性指数平均为0.36。高光干旱生长条件下,金钟藤叶片水浸液对生菜种子萌发和芽长生长的抑制作用较低,可能是因为在这种胁迫条件下,金钟藤降低了对竞争(化感)的资源投入。形态性状的可塑性可能促进了金钟藤在林下低光环境下更好的捕获光能和快速生长至冠层,而化感作用的可塑性说明金钟藤可能通过调节对竞争(化感)的资源投入来适应多样的水分条件。金钟藤在形态性状和化感作用方面的可塑性可能是其适应多样生境条件并爆发成灾的生理生态机制之一。
 

关键词: 生命表, 有效积温, 温度, 发育起点温度, 种群趋势指数

Abstract: Merremia boisiana is a native species in Hainan Province of China, and its population quantity has been rapidly increasing in recent two decades, which poses a heavy threat to many secondary forests, planted forests and shrublands. There are different light and water quantity conditions in habitats where populations of M. boisiana have broken out, and outbreak species usually adapt to diverse environmental conditions through high phenotypic plasticity. To reveal the ecophysiological mechanisms underlying the adaptation of the outbreak species M. boisiana to diverse environmental conditions, this study assessed the effects of different light and water availability on the growth, morphological traits and their plasticity, and allelopathy of M. boisiana through a greenhouse pot experiment. Biomass of M. boisiana decreased under high light intensity and drought. Low light increased total stem length, specific stem length, and specific leaf area, and decreased the root/shoot ratio of M. boisiana. The mean phenotypic plasticity index of these morphological traits was 0.36. Under high light and drought, aqueous leachates from dry leaves of M. boisiana were least inhibitory to seed germination and seedling shoot growth of Lactuca sativa var. ramosa, possibly because M. boisiana decreased its resource allocation to competition (allelopathy) under stress conditions. Plasticity in morphology might facilitate M. boisiana to better capture light as well as grow to the canopy at a faster rate under low light availability in the forest understory, while plasticity in allelopathy indicates that M. boisiana might adjust its resource allocation to competition (allelopathy) to adapt to various water conditions. We conclude that plasticity of M. boisiana in morphological traits and allelopathy might be one of the ecophysiological mechanisms of M. boisiana adapting to various environmental conditions and causing outbreak.

Key words: life table, effective accumulated temperature, population trend index, developmental threshold temperature, temperature