关键词: 可塑性, 克隆生长, 克隆形态, 交互移植-重

Abstract:

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.

Key words: Clonal growth, Clonal morphology, Reciprocal transplant-replant, Potentilla reptans var. sericophyll