外来树种火炬树化感作用的研究

Allelopathic Activity of Exotic Tree Rhus typhina

以盐肤木和黄栌为参照树种,用火炬树树叶水浸提液、林下土壤水浸提液浸种24 h,研究了浸提液对侧柏、油松、香椿、臭椿、小麦、小白菜种子萌发及幼苗生长的影响,研究了火炬树的化感作用。结果表明:火炬树完整鲜叶水浸提液处理小白菜种子,其发芽率和发芽势分别为88.0%、82.5%,与对照发芽率(94.0%)和发芽势(91.5%)无显著差异,而破碎鲜叶水浸液则极显著影响小白菜的发芽率和发芽势,分别降低为24.8%和5.0%;火炬树完整鲜叶和破碎鲜叶水浸液都能促进小白菜苗高生长,但都抑制小白菜胚根的伸长。与鲜叶相比,火炬树干叶水浸提液的化感作用明显降低。火炬树破碎鲜叶水浸提液极显著影响小麦发芽率,分别比对照的发芽率和发芽势降低11.0%和83.5%,干叶水浸提液则不影响小麦的发芽率,为95.0%,但发芽势比对照降低23.0%。与盐肤木和黄栌相比,火炬树破碎鲜叶水浸提液对小麦幼茎及胚根生长的抑制作用最强。火炬树破碎鲜叶水浸提液对4个乡土树种的种子萌发产生了不同程度的抑制作用,对香椿及臭椿发芽率的抑制作用极显著。火炬树破碎鲜叶水浸提液对4个树种的苗高以及油松苗胚根的伸长没有显著影响,但却极显著地抑制了侧柏、香椿及臭椿胚根的伸长。火炬树林下表层土壤水浸提液对小麦幼苗的生长没有抑制作用,能明极显著促进香椿的生长;处理55 d时,香椿苗平均高为8.63cm,极其显著高于对照(5.14 cm)。

Rhus chinensis and Cotinus coggygria as reference species, the allelopathic effect of aqueous extract of leaves of R. typhina and aqueous extract of under forest soil of R. growth typhina stands on seed germination and seedling of 6 different plant species were studied in order to objectively evaluate its biological invasion. The results indicated that the germination capacity and germination potential of Brassica chinensis treated by aqueous intact fresh leaf extract of R. typhina were 88.0% and 82.5% respectively,with no significance compared with those of the control, while water extract of fresh broken leaves showed a very significant effect on germination of B. chinensis,with germination capacity and germination potential being reduced to 24. 8% and 5. 0% respectively. The allelopathic effect of dry leaves was weaker than that of fresh leaves. Wheat seed germination capacity and germination potential markedly decreased as 12.0% and 94.9% as those of the control by water extract of broken fresh leaves, while water extract of broken dry leaves only inhibited germination potential, which was 26.1% lesser than that of the control. The inhibition of water extract of broken fresh leaves of R. typhina on young wheat stem growth and radicle growth was stronger than that of R. chinensis and C. coggygria. Water extract of broken leaf of R. typhina displayed inhibition on seed germination of four native tree species in different degrees with significant impact on germination capacity of Toona sinensis and Ailanthus altissima. Water extract of broken fresh leaves of R. typhina did not influence the stem growth of young seedlings of four tree species, as well as the radical growth of Pinus tabulaeformis, but it significantly inhibited the radicle elongation of Platycladus orientalis, T. sinensis and A. altissima. Water extract of surface soil under R. typhina stands showed no inhibition on wheat seedling growth and the growth of T. sinensis was significantly promoted to 8.63cm in height when it was cultivated for 55 days with the soil under R. typhina stands, compared to the control with 5.14 cm in height.