摘要
亚热带常绿阔叶林下分布着可塑性强的耐荫植物,其叶片应对外界干扰的防御对策至少有物理性防御和化学性防御两种,这两种防御代价在一定的昆虫取食压力下在理论上应该存在权衡.为检验这种权衡是否普遍存在,分别测定了重庆缙云山4个常绿物种——光叶山矾(Symplocos lancifolia)、四川山矾(S.setchuensis)、四川毛蕊茶(Camellialawii)和细枝柃(Eurya loquaiana)在林窗和林下两种对照光环境下个体叶片的光饱和下的净光合速率、叶面积干重和部分化学防御物质含量.结果表明,4个物种生活在林窗的个体单位叶面积干重、叶片氮含量和单位面积净光合速率通常高于林下的个体,但是单位质量和单位面积的总酚含量和C/N值却低于林下的个体.蛋白质和非结构性碳水化合物含量在不同生境中没有显著差异.因为不同物种叶片对光照条件的响应不同,不同参数的变化在两种生境间的差异并不完全一致.本研究结果在一定程度上暗示了物种在林窗和林下分别倾向于采取物理和化学性防御对策,并初步证实了两种防御强度之间存在权衡关系.
Shade-tolerant plants are usually phenotypically plastic in subtropical evergreen broad-leaved forests,and their leaves have at least two approaches to prevent insect herbivory,i.e.,physical and chemical defenses.According to resource allocation theory the two types of defensive costs should be negatively correlated.To examine whether the tradeoff between physical and chemical defenses is ubiquitous,light-saturated net photosynthetic rate,leaf mass per area（LMA）, and concentrations of some chemicals were examined for adult individuals of four evergreen broad-leaved species including Symplocos lancifolia,S.setchuensis,Camellia lawii and Eurya loquaiana living within forest gaps and under forest canopy in the Jinyun Mountain National Nature Reserve in Chongqing,China.For each species,the individuals within forest gaps were found to have higher LMA,nitrogen concentration and maximum net photosynthetic rate per unit area than those under forest canopy.In contrast,the individuals under canopy had higher total phenolics contents per leaf mass or per leaf area and C/N ratios relative to those within forest gaps;the contents of protein and total non-structural carbohydrate were indistinguishable between contrasting light conditions for each species.However,the light effect on leaf traits was sometimes species-specific, and not all the species showed the same response pattern for all the study parameters.In conclusion,our study suggests that the four species tend to adopt physical and chemical defensive strategies for their individuals growing under open and closed canopies,respectively,which indicates a tradeoff between the two defensive costs.Fig 4,Ref 40
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2010年第4期462-467,共6页
Chinese Journal of Applied and Environmental Biology
基金
中国科学院成都生物研究所知识创新领域前沿项目(No.08B2041)资助~~
关键词
单位叶面积干重
生活史权衡
物理防御
化学防御
亚热带常绿阔叶林
leaf mass per unit area
life history tradeoff
physical defense
chemical defense
subtropical evergreen broad-leaved forest
