Kuang Yuanwen, Xu Yimin, Zhang Lingling, Hou Enqing, Shen Weijun
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of SciencesGuangzhou, China.
Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of SciencesGuangzhou, China.
Front Plant Sci. 2017 May 15;8:802. doi: 10.3389/fpls.2017.00802. eCollection 2017.
It is well-known that drought has considerable effects on plant traits from leaf to ecosystem scales; however, little is known about the relative contributions of various traits within or between tree species in determining the plant's sensitivity or the tolerance to drought under field conditions. We conducted a field throughfall exclusion experiment to simulate short-term drought (∼67% throughfall exclusion during the dry season from October to March) and prolonged drought (∼67% throughfall exclusion prolonging the dry season from October to May) and to understand the effects of drought on two dominant tree species ( and ) in subtropical forests of southern China. The morphological, physiological, and nutritional responses of the two species to the two types of drought were determined. There were significantly different morphological (leaf max length, max width, leaf mass per area), physiological (leaf proline) and nutritional (P, S, N, K, Ca, Mg) responses by and to prolonged drought. Comparison between the drought treatments for each species indicated that the trees responded species-specifically to the short-term and prolonged drought, with exhibiting larger plasticity and higher adaption than responded more sensitively to prolonged drought in terms of morphology, proline content, and nutritional traits and to short-term drought with regard to soluble sugars content. The differential species-specific responses to drought will allow us to estimate the changes in dominant trees in subtropical forests of China that have experienced a decade's worth of annual seasonal drought.
众所周知，干旱对从叶片到生态系统尺度的植物性状有相当大的影响；然而，对于在田间条件下，不同树种内部或之间的各种性状在决定植物对干旱的敏感性或耐受性方面的相对贡献，人们了解甚少。我们进行了一项野外穿透雨排除实验，以模拟短期干旱（10月至3月旱季期间约67%的穿透雨排除）和长期干旱（10月至5月延长旱季期间约67%的穿透雨排除），并了解干旱对中国南方亚热带森林中两种优势树种（和）的影响。测定了这两个树种对两种干旱类型的形态、生理和营养反应。和对长期干旱的形态（叶片最大长度、最大宽度、单位面积叶质量）、生理（叶片脯氨酸）和营养（磷、硫、氮、钾、钙、镁）反应存在显著差异。对每个树种干旱处理之间的比较表明，树木对短期和长期干旱的反应具有物种特异性，在形态、脯氨酸含量和营养性状方面，比表现出更大的可塑性和更高的适应性，对长期干旱反应更敏感，对短期干旱的可溶性糖含量反应更敏感。不同树种对干旱的特异性反应将使我们能够估计中国亚热带森林中经历了十年季节性干旱的优势树种的变化。
