青藏高原东缘过路黄在资源交互斑块性生境中的克隆内资源共享

在青藏高原和四川盆地过渡带,分别于618m和1800m两个海拔高度上研究匍匐茎克隆植物过路黄(Lysimachia christinae)在资源交互斑块性生境中的克隆内资源共享及其对生长的影响.结果显示, 在海拔1800m处,与资源的空间同质性处理(Ⅰ) 和(Ⅱ)相比, 资源的空间异质性处理(Ⅲ)和(Ⅳ)下过路黄整个克隆片段的生物量和分株数均获得显著增加;在海拔618m处,与资源的空间同质性处理(Ⅰ) 和(Ⅱ)相比,资源的空间异质性处理(Ⅲ)和(Ⅳ)下过路黄整个克隆片段生物量显著增加.在海拔618m和1800m处,生长在低光高养条件下的远端分株, 若与高光低养的近端分株相连, 相比连接到低光高养的近端分株, 它们分配更多的生物量到地下部分;在海拔1800m处,生长在高光低养条件下的远端分株, 若与低光高养的近端分株相连, 相比连接到高光低养的近端分株, 它们分配更多的生物量到地上部分.在海拔618m和1800m处,生长在高光低养条件下的近端分株, 若与低光高养的远端分株相连, 相比连接到高光低养的远端分株, 它们分配更多的生物量到地上部分.处于资源交互斑块性生境中的过路黄发生了克隆内分工,依靠相连分株间的功能分化, 克隆植物能有效的利用异质性分布的资源, 缓解资源交互斑块性分布对克隆植物生长的不利影响.通过间隔子(匍匐茎或根状茎),相连分株间能够相互传递和共享由不同分株获得的资源,这种资源共享能够提高克隆植物在异质性生境中的存活与生长.同时,方差分析显示环境异质性和海拔的交互作用显著影响克隆片段的生物量和分株数.相比于海拔618m,在海拔1800m处克隆内资源共享对克隆植物生长表现的影响更大.

Intraclonal resource sharing of stoloniferous herb Lysimachia christinae in response to reciprocal patchiness of light and nutrients in the eastern edge of the Qing-Zang Plateau in China

Heterogeneity is a common feature of natural habitats and connected ramets of clonal plants may share resources under heterogeneous environments. Intraclonal resources sharing of the stoloniferous herb Lysimachia christinae, growing at two sites with different altitudes (618m above sea level and 1800m above sea level) in the transitional belt between the Qing-Zang Plateau and Sichuan basin, China, was investigated in response to the reciprocal patchiness of resources. The results indicate that biomass and number of ramets in the proximal part, the distal part and whole clonal fragments significantly increased in the resource heterogeneity treatments (Ⅲ)and(Ⅳ), compared with resource homogeneity treatments (Ⅰ) and(Ⅱ)at the site of 1800m above sea level; However, their biomass significantly increased in the resource heterogeneity treatments (Ⅲ)and(Ⅳ), compared with resource homogeneity treatments (Ⅰ) and(Ⅱ)at the site of 618m above sea level. At the two sites with different altitudes, the distal ramets growing in the treatment with low light and high nutrient allocated more biomass to the below-ground as connected to the proximal ramets growing in high light and low nutrient than as connected to the proximal ramets growing in low light and high nutrient. At the site of 1800m above sea level, the distal ramets growing in the treatment with high light and low nutrient allocated more biomass to the above-ground as connected to the proximal ramets growing in low light and high nutrient than as connected to the proximal ramets growing in high light and low nutrient. At the two sites with different altitudes, the proximal ramets growing in the treatment with high light and low nutrient allocated more biomass to the above-ground as connected to the distal ramets growing in low light and high nutrient than as connected to the distal ramets growing in high light and low nutrient. At both sites, therefore, L. christina ramets showed environmentally induced specialization for uptake of locally abundant resources, and intraclonal sharing of assimilates and nutrients between the interconnected ramets increased its performance. Finally, the significant interaction of habitat heterogeneity by altitude effect indicate that the effect of intraclonal resources sharing on the performance of Lysimachia christinae may be different between two sites with different altitudes. At the site of 1800m above sea level, the effect of intraclonal resource sharing on growth performance of clonal plants was greater than that in the site of 618m above sea level. Thus, the contribution of intraclonal resources sharing to the success of clonal plant species may be different in various natural habitats.