银合欢对2种边坡恢复先锋植物的化感作用

为了探讨银合欢引种栽培可能存在的化感作用及其对银合欢林管理的意义,以狗牙根和紫花苜蓿为受体植物,测试了银合欢鲜根和叶片凋落物的水浸提液对受体植物种子萌发、幼苗存活和幼苗生长的影响。结果表明:银合欢鲜根和叶片凋落物水浸提液对2种受体植物的种子萌发和幼苗存活都表现为抑制作用,抑制作用随浓度增加而增强。其中鲜根水浸提液对紫花苜蓿的影响显著,但对狗牙根的作用不显著。当鲜根水浸提液浓度为0.125 g·m L-1时,紫花苜蓿的种子发芽率和幼苗存活率分别比对照低21.06%和28.59%。叶片凋落物水浸提液对2种植物种子萌发及对紫花苜蓿幼苗存活的影响都达到显著水平,而对狗牙根幼苗存活的影响不显著。当叶片凋落物水浸提液浓度为0.125 g·m L-1时,紫花苜蓿的发芽率和幼苗存活率分别比对照低30.14%和15.71%,狗牙根的发芽率比对照低49.08%。银合欢鲜根和叶片凋落物水浸提液对2种受体植物的幼苗生长都有促进作用,促进作用随浓度升高而降低。银合欢叶片凋落物水浸提液的化感效应明显强于鲜根水浸提液,紫花苜蓿对化感作用的响应强度大于狗牙根。

Allelopathy of Leucaena leucocephala on two pioneer species used in slope ecological restoration

In order to uncover the possible allelopathy of Leucaena leucocephala (Lam.) de Wit on native species and its implication for forest management, the effects of aqueous extracts of fresh root and leaf litter on seed germination, seedling survival and seedling growth were tested using Cynodon dactylon Linn. and Medicago sativa Linn. as recipients. The results showed that both the aqueous extracts of L. leucocephala fresh root and leaf litter inhibited seed germination and seedling survival of the two species, and the inhibition increased with the concentration growing. Among of them, the fresh root extracts significantly inhibited seed germination and seedling survival of M. sativa, but not significantly on C. dactylon. The seed germination rate and seedling survival rate of M. sativa reduced by 21.06% and 28.59%, respectively, when adding the fresh root extracts at the concentration of 0.125 g·mL-1 , compared with the control group. The leaf litter extracts had significant inhibition on seed germination of both species and seedling survival of M. sativa, but no significant inhibition on seedling survival of C. dactylon. Comparing with the control group, the seed germination rate and seedling survival rate of M. sativa reduced by 30.14% and 15.71%, respectively, and seed germination rate of C. Dactylon, reduced 49.08% when adding the leaf litter extracts at a concentration of 0.125 g·mL-1 . The aqueous extracts of fresh root and leaf litter of L. leucocephala promoted seedling growth of two recipients and the effect decreased with the concentration increasing. The allelopathic effect of leaf litter aqueous extracts was stronger than that of fresh root aqueous extracts. The response of M. sativa to the allelopathy of L. leucocephala was more sensitive than that of C. dactylon.