清凉峰不同海拔木本植物小枝内叶大小-数量权衡关系  

Trade-off between leaf size and number in current-year twigs of deciduous broad-leaved woody species at different altitudes on Qingliang Mountain,southeastern China

作　　者：杨冬梅[1] 占峰 张宏伟 

机构地区：[1]浙江师范大学化学与生命科学学院,浙江金华321004 [2]桐城高等师范专科学校,安徽桐城231400 [3]浙江清凉峰国家级自然保护区管理局,浙江临安311321

出　　处：《植物生态学报》2012年第4期281-291,共11页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31000193)资助

摘　　要：权衡关系是生活史对策理论的基础,叶大小-数量的权衡关系对理解叶大小进化具有重要的意义。该研究以单叶面积和单叶片干重表示叶大小,用小枝干重和小枝茎干重表示小枝大小,采用标准化主轴估计(standardized major axis estima-tion,SMA)和系统独立比较分析(phylogenetically independent contrast analysis,PIC)的方法,对浙江省清凉峰自然保护区3个不同海拔落叶阔叶木本植物当年生小枝内的叶大小与数量间的关系进行研究。结果显示,无论叶大小和小枝大小是用面积或干重表示,在每个海拔,叶大小与出叶强度均存在显著的等速负相关关系,表明在落叶阔叶木本植物中发现的叶大小与出叶强度之间的权衡关系在不同生境物种中是普遍存在的,植物在叶大小方面的种间变化,可能不是自然选择的直接产物,而是叶片数量变化权衡关系的一个副产物。不同海拔间的比较显示,高海拔物种的叶面积或干重与出叶强度相关关系的y轴截距比中、低海拔物种小,表明在出叶强度一定的情况下,高海拔物种比低海拔物种具有更小的叶大小。与高海拔物种相比,中海拔物种的共同斜率沿共同主轴有一个向上的位移,表明中海拔物种比高海拔物种具有更大的叶大小,但出叶强度更小。这些结果表明生境对叶大小-数量的权衡关系具有显著的影响,中海拔生境具有更适宜植物生长的气候及养分条件,而高海拔的低温等不利影响使得叶片变小。Aims Trade-offs are fundamental to life-history strategies theory,and the leaf size and number trade-off is an important determinant of leaf-size evolution.It also has been proposed that this trade-off is dependent on habitat,but this is not well tested.Our objectives were to test whether the negative,isometric relationship between leaf size and number is conserved in different habitats and to explore the effects of altitude change on the relationship between the leaf size and number.Methods Leaf area,mass and number and twig mass and stem mass of current-year twigs were measured for 61 deciduous broad-leaved woody species within three altitude-based habitats on Qingliang Mountain,southeastern China.The standardized major axis estimation method and the phylogenetically independent contrast method were used to examine the scaling relationship between leaf size （leaf mass and leaf area） and leafing intensity （twig mass and stem mass） within current-year twigs.Important findings Significantly negative and isometric scaling relationships between leaf size and leafing in-tensity were found to be consistent in all three altitude-based habitats,regardless of whether leaf/twig size was expressed as area or mass.However,the intercepts of these relationships significantly decreased with increasing altitude,suggesting that habitats constrain the leaf size that can be supported by a given leafing intensity.The middle-attitude species usually had significant upper shifts along the common slopes relative to the high-altitude species.This suggested that the middle altitude is a more suitable habitat with high nutrients and moderate climate conditions for plants,compared to the high altitude with low temperatures and nutrients.

关 键 词：生境 叶大小 出叶强度 权衡关系 

分 类 号：S718.4[农业科学—林学]