濒危植物永瓣藤叶片功能性状对环境因子的响应

植物叶片功能性状能够响应环境条件的变化,反应了植物对环境的适应策略。当前,针对藤本植物叶片功能性状地理格局及其环境驱动力的研究较少。以国家重点保护植物永瓣藤（Monimopetalum chinense）为研究对象,对其分布区内11个种群的15个叶片功能性状进行测量,并结合气候、土壤因子来解释叶性状变异。比较叶片性状在局域和区域尺度上的种内变异程度,利用多元逐步回归分析环境因子对叶性状的影响。结果表明,在局域尺度上,永瓣藤叶功能性状变异系数介于3.0%-22.5%,其中,叶面积变异程度最大,叶片碳含量变异最小。永瓣藤叶片形状随纬度上升而变得宽且圆。叶片磷含量相对较低,永瓣藤的生长可能受到了磷限制。土壤与气候因子是叶片性状的重要驱动因素,解释了25%-97%的叶片性状变异。在温度和水分充足的情况下,永瓣藤叶片趋向于的慢速生长的保守策略。总体来说,永瓣藤叶片功能性状通过一定的种内变异和性状组合,并与气候、土壤因子相互作用,适应当前的环境条件。

Response and adaptation of leaf functional traits of an endangered liana Monimopetalum chinense to environmental factors

Leaf functional traits can respond to the changes of environmental conditions and reflect adaptation strategies of plants to environments. At present, there are few studies on the geographical pattern of leaf functional traits and their environmental drivers of lianas. Here, we measured 15 leaf functional traits of an endangered liana species Monimopetalum chinense (Celastraceae) in 11 populations across its natural distribution range in China, and combined climate factor and soil factor to explain trait variation. We investigated the extent of trait variation at local and regional scales, and analyzed the influence of environmental factors on leaf traits by multiple stepwise regression. The coefficients of variation of leaf functional traits was different, the fold range of variation of leaf traits ranged from 1.03 to 1.80 times. The traits variation value of local scale was higher than regional scale. At regional scale, the coefficients of variation of leaf traits functional ranged from 1.1% to 15.5%. At local scale, the coefficient of variation of leaf traits functional ranged from 3.0% to 22.5%. Among these two scales, the variation degree of leaf area was the largest and the variation degree of leaf carbon content was the smallest. The morphology of the leaves was affected by the latitudinal gradient, leaf length-width ratio decreased significantly as latitude increased, and the leaf morphological factor increased significantly as latitude increased. Leaf shape became wider and more round as latitude increased to increase the thickness of the leaf boundary and reduce the hydrothermal dissipation of the leaves. Leaf phosphorus content was relatively low, and the soil available phosphorus content in the distribution area of M. chinense was also low, indicating that the growth of M. chinense might be limited by phosphorus. There was no any single environmental factor could explain all leaf trait, the association between environmental factors and leaf functional trait was complex. Soil and climate factors were strong predictors of leaf trait, and 25%-97% of leaf trait could be explained. Soil pH, soil nitrate nitrogen, and soil available phosphorus were the dominant pridcetors for the of leaf traits of M. chinense, the mean annual temperature and annual precipitation could also affect the of some leaf traits. Under the condition of sufficient temperature and water, the leaf of M. chinense tended to be a conservative strategy of slow growth. Overall, M. chinense leaves adapted to environments by intraspecific variation and combination of traits, as well as the associations with climate and soil factors.