三种高寒植物幼苗生物量分配及性状特征对光照和养分的响应

为了解高寒植物幼苗对生境资源异质性的适应策略,以高寒草甸中常见的3种草本植物大耳叶风毛菊(Saussurea macrota)、甘西鼠尾草(Salvia przewalskii)和千里光(Senecio scandens)为材料,比较研究了这3种植物幼苗对不同光照和养分资源的响应。结果表明:光照和养分异质性显著影响了3种植物幼苗的性状特征和生物量分配,并存在一定的交互影响。随着光照的降低,3个物种的幼苗的生物量和根分配呈现降低趋势,但是其株高、比叶面积、叶分配、茎分配却逐渐升高。在低养分条件下,3个物种幼苗的总生物量、株高、比叶面积和叶分配均降低,而根分配均却显著增加。对于光照和养分资源异质性而言,光照异质性对高寒植物生物量分配和性状特征的改变具有更大的影响。喜阴物种大耳叶风毛菊和喜光物种甘西鼠尾草比中性生境物种千里光表现出了较大的性状特征和生物量分配的可塑性指数。

Response of biomass allocation and morphological characteristics to light and nutrient resources for seedlings of three alpine species

Microhabitat variety shows significant effects on plant morphological performances. To understand adaptation strategy of alpine species to resources heterogeneity, response of biomass allocation and morphological characteristics to nutrient and light heterogeneity were studied for three component species (Saussurea macrota, Salvia przewalskii and Senecio scandens) in alpine meadow of the Qinghai-Tibetan Plateau. Results showed that light and nutrient availability both had significant effects on biomass allocation and morphological characteristics. And, there were some interaction effects between them. For all seedling morphological performances in this study, there was a significant difference among species. There were lower biomass and root allocation, and higher individual height, specific leaf area, leaf allocation and stem allocation in lower light availability. Biomass, height, specific leaf area, leaf allocation all decreased in lower nutrient availability, but root allocation increased significantly. Results revealed that light availability play a more important role in acting on seedling biomass allocation and morphological plasticity than nutrient availability in alpine meadow. Finally, sciophilous species Saussurea macrota and light-loving species Salvia przewalskii presented larger plasticity indexes in biomass allocation and morphological characteristics than neutral-habitat species Senecio scandens.