低光下薇甘菊茎的伸长特征及其生理基础

Stem Elongation Characteristics of Mikania micrantha and Its Physiological Basis under Low Light Condition

摘要:

为了解薇甘菊（Mikania micrantha）成功入侵森林群落的机制，通过模拟林下低光（30%自然光强），对遮阴下的茎伸长特征、光合特性及其生长调节剂的变化进行了研究。结果表明，在低光下薇甘菊茎的细胞分裂素、赤霉素和生长素含量显著增加；茎仍具有较高的净光合作用能力[P_n=（1.22±0.13）μmol/（m²·s）]。因此，薇甘菊通过维持较高的光合效率为茎的伸长提供物质基础，同时合成更多的植物生长调节剂调控物质的再分配，将更多的生物量分配到茎，从而实现了主茎在低光下的快速伸长，这是薇甘菊克服低光限制从而入侵成功的重要机制之一。

Abstract:

In order to understand the successful invasion mechanism of Mikania micrantha in forest community, the stem elongation characteristics, photosynthetic characteristics and changes in growth regulators of M. micrantha under shade were studied by simulating low light under forest (30% natural light). The results showed that the contents of cytokinin, gibberellin and auxin increased significantly in stem under low light, and the net photosynthetic rate (P_n) of stem was still very high at (1.22±0.13)μmol/(m²·s). Therefore, M. micrantha maintained a high photosynthetic efficiency to provide material basis for rapid elongation of stem and synthesized more growth regulators to control the redistribution of substances and allocate more biomass to the stem, so as to enable the stem to elongate rapidly under low light, which was one of the important factors forM. micrantha to overcome the limitation of low light and then successfully invaded.