The role of perennation traits in plant community soil frost stress responses.
The role of perennation traits in plant community soil frost stress responses.
复制标题
多年生性状在植物群落土壤霜冻胁迫反应中的作用。
作者：
F. Lubbe;H. Henry
背景和目标
草本植物可以作为地下结构或种子在长期冰冻时期生存，可以通过土壤、枯枝落叶或雪与冷空气隔离。地下多年生结构的形式和暴露于土壤霜冻的程度各不相同，因此这种结构变化对于确定植物群落对霜冻胁迫的反应可能很重要。
方法
我们在北温带老田进行了三年多的除雪实验，以检查基于地下多年生特征的不同植物功能群的相对冰冻反应。第三年增加了垃圾清除处理。物种级覆盖百分比数据于五月、六月和九月记录，然后按功能组汇总。
主要成果
除雪减少了植物总覆盖率，对于直根和根茎物种来说，这种反应在年份中尤其强烈且一致。多年来，带根芽和新芽植物的覆盖物除雪反应从积极反应到消极反应各不相同。随着除雪的影响，砧木植物的覆盖度不断增加。根茎物种通常最容易受到垃圾清除的影响。
结论
这项研究首次探讨了霜冻严重程度的变化对不同植物多年生性状功能群反应的影响。由于积雪减少和温度变化增加，未来几十年北温带地区草本植物对霜冻的反应可能变得越来越重要。我们的结果揭示了多年生性状功能群之间的响应存在显着差异，这可能会导致物种丰度的变化以响应土壤霜冻的变化。
BACKGROUND AND AIMS
Herbaceous plants can survive periods of prolonged freezing as belowground structures or seed, which can be insulated from cold air by soil, litter or snow. Belowground perennial structures vary in both form and their exposure to soil frost, and this structural variation thus may be important in determining the responses of plant communities to frost stress.
METHODS
We conducted a suite of snow removal experiments in a northern temperate old field over three years to examine the relative freezing responses of different plant functional groups based on belowground perennation traits. A litter removal treatment was added in the third year. Species-level percent cover data were recorded in May, June, and September then pooled by functional group.
KEY RESULTS
Snow removal decreased total plant cover, and this response was particularly strong and consistent among years for tap-rooted and rhizomatous species. The snow removal responses of cover for plants with root buds and new recruits from seed varied from positive to negative responses among years. The cover of rootstock plants consistently increased in response to snow removal. Rhizomatous species were generally the most vulnerable to litter removal.
CONCLUSIONS
This study is the first to explore the effects of variation in frost severity on the responses of different plant perennation trait functional groups. The responses of herbaceous species to frost may become increasingly important in northern temperate regions in the coming decades as a result of declining snow cover and increasing temperature variability. Our results reveal substantial variation in responses among perennation trait functional groups, which could drive changes in species abundance in response to variation in soil frost.