南亚热带阔叶林展叶物候及其种内种间差异探讨

Intra-and inter-specific variations of the leaf unfolding phenology in a subtropical broad-leaved forest

植物的展叶物候与植物的生长和生存密切相关,但未见有定性的研究植物展叶物候的种间和种内差异与验证亚热带常绿阔叶林植物展叶物候系统发育关系的报道。为了更好地理解南亚热带常绿阔叶林物种共存机制和预测不同物种对气候变化的响应,该研究于2013年1月至2014年12月期间,在中国科学院华南植物园鼎湖山自然保护区内对44个树种的展叶物候进行了连续观测,利用变异系数定性分析了气候因子、系统发育关系对展叶始期及其种内和种间差异和展叶期的影响。结果表明:鼎湖山自然保护区植物展叶始期主要集中在3-5月,植物展叶物候受气候因子影响不显著;不同物种的展叶物候种内变异差别较大,其中种内差异最大的是红皮紫棱(Craibiodendron kwangtungense)(变异系数为0.74),最小的是广东润楠(Machilus kwangtungensis)(变异系数为0.09);基于APGⅢ物种数据库构建谱系树,发现植物间的系统发育关系对展叶物候无显著影响,即亲缘关系近的物种,展叶期并不相似。该研究结果对于理解生态系统过程,如碳循环、物质能量流动,以及展叶物候对气候变化的适应性具有重要意义。

Leaf unfolding phenology in plants can be determined by genetic factors,biotic and abiotic environmental factors. However,limited information was available about the leaf unfolding phenology of evergreen broad-leaved forest,and its phylogenetic conservatism has not been investigated. In order to better understand the maintaining mechanism of species coexistence in lower subtropical evergreen broad-leaved forest and to predict species responses to global changes,we used the phenological data of 44 species containing 112 individuals of trees,which obtained from Dinghushan （DHS） Arboretum,Chinese Academy of Sciences （CAS）,to explore the effects of climate,phylogenetic and the intra-and inter-specific variations on leaf unfolding date. The results showed that leaf unfolding date in DHS National Nature Reserve peaked in the period from March to June,and had been little influenced by climate factors. There were distinct intraspecific variation between different species,and Craibiodendron scleranthum var. kwangtungense showed the greatest coefficient of variation （CV,0.74）,while Machilus kwangtungensis had the smallest coefficient of variation （CV,0.09）. According to the phylomatic tree based on APG Ⅲ,no significant effect of phylogeny on the leaf unfolding date was detected,indicating that close related species did not have the tendency to leaf-out at similar time. This study suggests that exploring the intra-and inter-specific variations of leaf unfolding phenology is important for understanding the ecosystem processes,such as the carbon cycle,the material and energy flow,and the adaptation of different tree species to climate changes.