Liu Ruihua, Chen Qiuwen, Dong Bicheng, Yu Feihai
Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
1] Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China [2] Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing 210009, China.
Sci Rep. 2014 Jul 1;4:5507. doi: 10.1038/srep05507.
Some introduced clonal plants spread mainly by vegetative (clonal) propagules due to the absence of sexual reproduction in the introduced range. Propagule pressure (i.e. total number of propagules) may affect the establishment and thus invasion success of introduced clonal plants, and such effects may also depend on habitat conditions. A greenhouse experiment with an introduced plant, Hydrocotyle vulgaris was conducted to investigate the role of propagule pressure on its invasion process. High (five ramets) or low (one ramet) propagule pressure was established either in bare soil or in an experimental plant community consisting of four grassland species. H. vulgaris produced more total biomass under high than under low propagule pressure in both habitat conditions. Interestingly, the size of the H. vulgaris individuals was smaller under high than under low propagule pressure in bare soil, whereas it did not differ between the two propagule pressure treatments in the grassland community. The results indicated that high propagule pressure can ensure the successful invasion in either the grass community or bare soil, and the shift in the intraspecific interaction of H. vulgaris from competition in the bare soil to facilitation in the grassland community may be a potential mechanism.
一些引入的克隆植物由于在引入范围内缺乏有性繁殖，主要通过营养（克隆）繁殖体进行传播。繁殖体压力（即繁殖体总数）可能会影响引入的克隆植物的定殖，进而影响其入侵成功，而且这种影响可能还取决于栖息地条件。我们以一种引入植物——铜钱草开展了一项温室实验，以研究繁殖体压力在其入侵过程中的作用。在裸土或由四种草地物种组成的实验植物群落中，分别设置了高（五个分株）或低（一个分株）繁殖体压力。在这两种栖息地条件下，铜钱草在高繁殖体压力下产生的总生物量均高于低繁殖体压力下的。有趣的是，在裸土中，高繁殖体压力下铜钱草个体的大小小于低繁殖体压力下的，而在草地群落中，两种繁殖体压力处理下的个体大小没有差异。结果表明，高繁殖体压力能够确保在草地群落或裸土中成功入侵，而铜钱草种内相互作用从裸土中的竞争转变为草地群落中的促进作用可能是一种潜在机制。
