摘要
植物的叶片结构和功能性状受到自身、环境和系统发育的影响。该研究选取西双版纳20 hm2热带雨林动态监测大样地内18种分布格局不同的大戟科植物,测量了幼树叶片的解剖结构、水分关系特征、最大光合能力和暗呼吸,主要探讨了叶片结构对植物耐旱性和光合能力的影响,耐旱性和光合能力之间的权衡关系,以及环境水分条件对植物功能性状相关性的影响。结果表明:1)生境内植物表现出一定的结构和功能的趋同性,分布在山脊和山坡的种比沟谷种具有更强的耐失水能力;2)去除了系统发育的影响后,一些关键性状(特别是叶片密度和膨压丧失点时的水势、饱和渗透势等)之间存在跨生境尺度上的相关关系,植物叶片结构同时影响了植物的耐失水能力和光合能力,植物叶片自身的结构限制导致了植物的耐旱性(高的叶片密度、比叶质量)和光合能力(低的叶片密度、比叶质量)存在反向进化关系;3)如果研究的植物类群亲缘关系较近,传统的Pearson相关分析不能很好地揭示其性状间的相关关系,因而必须采用系统发育独立对照差作相关分析。大戟科植物的结构和功能在水分梯度和光梯度上的生态位分化也从功能性状的角度为热带季雨林能维持高生物多样性,保持植物物种长期共存提供了一个可能的解释。
Aims Leaf structural and functional traits have been extensively studied to explain community assembly mecha- nisms, species distributions, niche differentiations, and even ecosystem services functions. However, these traits are influenced by both environment and phylogeny, showing correlations or trade-offs among them. In this study, we assessed the impacts of leaf structure on drought tolerance and photosynthetic potential, and the trade-off be- tween drought tolerance and photosynthetic capacity, to provide an explanation for species coexistence and the maintenance of high biodiversity in tropical rainforests. Methods We chose 18 species in the Euphobiaceae family differing in distribution patterns along topographic gra- dients in a 20 hm2 forest dynamics monitoring plot （FDP） in Xishuangbanna. We measured leaf anatomy, leaf water relations characteristics, maximum photosynthetic rate, and dark respiration, and used two different methods--the tradi- tional Pearson correlation and phylogenetic independent contrasts--to analyze the relationships among those traits. Important findings We found that： 1） species showed convergence in structures and functions within specific habitat; species on ridge or slope had a stronger water loss-tolerance abilities than species in the valley. 2） Corre- lations among some key traits （specifically, leaf density, water potential at turgor loss point, and water potential at full turgor, etc.） were found among habitats; plants adjusted leaf structure to influence simultaneously plant water loss-tolerance abilities and photosynthetic capability, which may result in a trade-off between drought tolerance （high leaf density, leaf mass per area） and photosynthetic phylogenetic independent contrasts must be used when capability （low leaf density, leaf mass per area）. 3） The analyzing correlations among the traits of genetically related species due to the weakness of traditional Pearson analysis. The ecological niche differentiation to water and light gradients as revealed by the present study provides a potential explanation for the high diversity of the seasonal tropical rainforest.
出处
《植物生态学报》
CAS
CSCD
北大核心
2014年第4期311-324,共14页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(31170399)
关键词
暗呼吸
生境
叶片解剖结构
光合作用
压力-容积曲线
dark respiration, habitat, leaf structure, photosynthesis, pressure-volume curve
