高寒山区混播草地燕麦和毛苕子种间的竞争关系

Interspecific competition between Avena sativa and Vicia vilosa in mixed sowing grassland in alpine mountainous region

植物通过调整生长发育阶段的生长行为和形态特征来适应种间竞争关系的变化。在祁连山区建立了禾本科牧草燕麦与豆科毛苕子混播草地,以相对产量(RY)、相对密度(RD)和相对产量总值(RYT)为指标,研究了这2种1年生植物在不同物候期的种间竞争关系。结果表明:随着物候期的变化,种间竞争关系发生着动态变化,在出苗期,二者存在激烈的种间竞争,2个物种限制彼此相对数量的发展,株高、叶片数等增长缓慢;分蘖期,种间竞争转换为种间协作,分蘖数、叶片数等迅速增大,相对产量总值不断积累;进入拔节期,毛苕子开始扩大相对数量,限制了燕麦的生长,导致了激烈的种内竞争;到结实期,种内竞争再次转化为种间竞争。不同物候期的燕麦和毛苕子通过对植物形态可塑性的调整,更好地响应了种间竞争关系的转换。

Plants can adapt to interspecific competition by adjusting their growth behaviors and morphological characteristics at their different growth stages. In this study, a grassland with mixed sowing Arena sativa and Vicia vilosa was established in Qilian mountainous region, aimed to understand the interspecific competitive relationships of the two annual species at their different phonological phases. To evaluate the competitive relationships, the relative yield （RY）, relative density （RD）, and relative yield total （RYT） of the two species were measured. It was observed that the interspecfic relationships of the two species changed with phenological phase. At seeding stage, there was a strong competition between the two species, manifesting in the mutual limitation of relative number and the slow increase of plant height and leaf number; at tillering stage, the in- terspecfic competition transformed into interspecfic collaboration, manifesting in the rapid increase of tiller number and leaf number and the increasing RYT; at jointing stage, V. vilosa started to increase its relative number, which limited the development of A. sativa and caused strong intraspecfic competition; at grain-filling stage, the intraspecfic competition transformed into interspecific competition again. Through the adjustment of morphological plasticity at different phonological phases, the two species better responded the transformation of their interspecfic relationship.