5种植物水浸液对西藏长鞭红景天种子萌发的化感作用

Allelopathic Effects of Aqueous Extracts from Several Species of Plants on Rhodiola fastigiata in Tibet Plateau

为了探明长鞭红景天(Rhodiola fastigiata)在西藏色季拉山地区种群面积缩小、数量减少的原因,研究了长鞭红景天群落内急尖长苞冷杉(Abies georgeivar.smithii)、硬叶柳(Salixsclerophylla)、锦丝藓(Actinothuidiumhookeri)、雪层杜鹃(Rhododendron nivale)及自身的水浸提液对其种子萌发和幼苗生长的影响。结果表明:长鞭红景天自身的水浸提液对其种子的萌发有一定的促进作用,其他4种植物的茎叶水浸提液对长鞭红景天幼苗芽和根的伸长生长的抑制作用达显著程度,当相对质量浓度≥0.02 g.mL-1时,急尖长苞冷杉和硬叶柳对长鞭红景天种子的萌发率和发芽速率的抑制作用均达显著程度,并随质量浓度的增加抑制作用更为明显,说明长鞭红景天伴生种的茎叶水浸提液的化感物质对其有性繁殖有一定的抑制作用,同时也降低了长鞭红景天与同一生境中其他物种的竞争力。

An experiment was conducted to study the influence of aqueous extracts separately from Abies georgei var. smithii, Salix selerophyUa, Actinothuidium hooked, Rhododendron nivale on seed germination and growth of Rhodiola fastigiata in order to find out the reason of decrease in distribution area and population size of R. fastigiata in Mount Sejila region. The effect of the aqueous extracts from R. fastigiata itself was also studied. Results showed that the aqueous extracts from R. fastigiata itself had promotion effects to some extent, but the aqueous extracts from stems and leaves of the other four species had very significant inhibition effects on protraction growth of plumule and radicle of R. fastigiata. When the concen-tration of aqueous extracts was higher than or equaled to 0.02g·mL^-1, the aqueous extracts from A. georgei vat. smithii and S. sclerophylla exhibited significant inhibition effects on seed germination rate, germination speed and protraction growth of R. fastigiata, and this inhibition effects was more significant with aqueous extracts concentration increasing. Thus, allelopathic effects greatly restrain sexual reproduction of R. fastigiata and reduced the competitiveness of R. fastigiata with other species in the same habitat.