PDF(Pubmed)
Abstract：
Plants from invasive populations often have higher growth rates than conspecifics from native populations due to better environmental adaptability. However, the roles of improved chlorophyll fluorescence or antioxidant defenses in helping them to grow better under adverse situations are insufficient, even though this is a key physiological question for elucidating mechanisms of plant invasion. Here, we conducted experiments with eight native (China) and eight introduced (USA) populations of Chinese tallow tree (Triadica sebifera). We tested how salinity, nutrients (overall amount or N:P in two separate experiments) and their interaction affected T. sebifera aboveground biomass, leaf area, chlorophyll fluorescence and antioxidant defenses. Plants from introduced populations were larger than those from native populations, but salinity and nutrient shortage (low nutrients or high N:P) reduced this advantage, possibly reflecting differences in chlorophyll fluorescence based on their higher PSII maximum photochemical efficiency (F v/F m) and PSI maximum photo-oxidizable P700 in higher nutrient conditions. Native population plants had lower F v/F m with saline. Except in high nutrients/N:P with salinity, introduced population plants had lower electron transfer rate and photochemical quantum yield. There were no differences in antioxidant defenses between introduced and native populations except accumulation of hydrogen peroxide (H2O2), which was lower for introduced populations. Low nutrients and higher N:P or salinity increased total antioxidant capacity and H2O2. Our results indicate that nutrients and salinity induce differences in H2O2 contents and chlorophyll fluorescence characteristics between introduced and native populations of an invasive plant, illuminating adaptive mechanisms using photosynthetic physiological descriptors in order to predict invasions.
摘要：
由于更好的环境适应性，来自入侵种群的植物通常比来自本地种群的物种具有更高的生长速率。然而,改善叶绿素荧光或抗氧化剂防御在帮助它们在不利情况下更好地生长的作用是不够的，尽管这是阐明植物入侵机制的关键生理问题。这里,我们对中国牛脂树（Triadicasebifera）的八个本地（中国）和八个引进（美国）种群进行了实验。我们测试了盐度，养分（总量或N：P在两个单独的实验中）和它们的相互作用影响T.sebifera地上生物量，叶面积,叶绿素荧光和抗氧化防御。引进种群的植物比本地种群的植物大，但是盐度和营养缺乏（低营养或高N：P）降低了这种优势，在较高的营养条件下，基于较高的PSII最大光化学效率（Fv/Fm）和PSI最大光氧化P700，可能反映了叶绿素荧光的差异。本地种群植物在盐水中的Fv/Fm较低。除了高养分/N：P与盐度，引种群体植物的电子转移速率和光化学量子产率较低。除了过氧化氢（H2O2）的积累外，引入种群和天然种群之间的抗氧化防御没有差异，对于引进人口来说，这一比例较低。低养分和较高的N：P或盐度增加了总抗氧化能力和H2O2。我们的结果表明，养分和盐度会引起入侵植物的引入种群和本地种群之间H2O2含量和叶绿素荧光特性的差异，使用光合生理描述符阐明适应机制以预测入侵。
