林下和林窗内绢毛匍匐委陵菜的克隆生长和克隆形态

 为了验证绢毛匍匐委陵菜(Potentilla reptans var. sericophylla)林窗和林下种群间的行为差异是完全由表型可塑性引起，还是局部分化的结果，将生长在北京东灵山油松（Pinus tabulaeformis）林林窗和林下的绢毛匍匐委陵菜，进行生境间的交互移植-重植野外生态实验。研究结果表明，实验植物的叶片长度、叶片宽度、叶柄长度和匍匐茎节间长度等克隆形态特征在两生境间无差异。两个来源的植株，其基株生物量、基株分株数和基株匍匐茎总长度等克隆生长特征在林下生境中都比在林窗生境中小，表现出显著的可塑性。所研究的克隆形态特征和克隆生长特征及其可塑性在不同生境来源的实验植物间没有差异。绢毛匍匐委陵菜克隆形态特征和克隆生长特征及其可塑性在林下和林窗生境间没有发生局部分化，林窗为其较适生境，克隆生长特征的可塑性对绢毛匍匐委陵菜利用生境异质性可能具有重要意义

CLONAL GROWTH AND CLONAL MORPHOLOGY OF POTENTILLA REPTANS VAR. SERICOPHYLLA IN FOREST UNDERSTOREY AND GAP

A reciprocal transplant-replant experiment was carried out to investigate clonal plasticity and local specialization of forest gap population and forest undergrowth population of a stoloniferous herb Potentilla reptans var. sericophylla in the Pinus tabulaeformis forest at Dongling Mountain, Beijing. The experiment was conducted from 19 May to 23 August 1996 in Dongling Mountain (115°26′-115°30′E，40°00′-40°02′N), 114 km southwest of Beijing. At the beginning of the experiment, one forest gap population and one forest undergrowth population of Potentilla reptans var. sericophylla in the Pinus tabulaeformis forest was selected. In each population, 120 ramets of Potentilla reptans var. sericophylla were selected at random as target plants. Target plants experienced one of four treatments during the experiment. 1) Half of the target ramets in the forest gap population were transplanted to the forest understorey. 2) The other half in the forest gap was replanted in their native site. 3) Similarly, half of the target ramets in the forest undergrowth were transplanted to the forest gap. 4) The other half in the forest understorey was replanted in their native site. The distance between the two field experiment sites was about 100 m. The gap was about 15 years old. During the experiments, the experimental plants all grew naturally. There were three times of harvesting on 23 June, 23 July and 23 August, 1996. In each of the harvests, 20 target ramets were chosen randomly and harvested for each of the treatments. The genet biomass, ramet number, blade length, blade width, petiole length, stolon internode length and total stolon length were measured after each harvest to investigate clonal plasticity and local specialization. A One-way and a Two-way ANOVA, with the native habitat and the growing habitat of the experiment plants as the main effects (GLM procedure, SAS), were applied for analyzing responses in all measured characters. The results show that the biomass, number of ramets and total stolon length of the experimental plants under the forest undergrowth was smaller than those under the forest gap. Petiole length, leaf blade width, leaf blade length and internode length did not differ between the different growing habitats. The plants from the forest gap grew better than those from the forest undergrowth. These results indicate that there was no local specialization in the plasticity of characters related to clonal growth and clonal morphology in forest gap and forest undergrowth. Clonal plasticity rather than local specialization is the main strategy of Potentilla reptans var. sericophylla in heterogeneous habitats.