不同发育期反枝苋对黄瓜根缘细胞的化感作用

The allelopathy of different development stages of Amaranthus retroflexus L. on root border cells of cucumber

以黄瓜为实验材料,采用悬空气培养法研究了不同发育期反枝苋水浸提液对根缘细胞的化感效应。结果表明:在反枝苋水浸提液作用下,黄瓜根果胶甲基酯酶(PME)活性升高,但随着水浸提液浓度的升高,这种促进效应逐渐降低;而黄瓜根缘细胞存活率随着水浸提液浓度的升高而下降。相同发育期反枝苋不同部位的化感作用差异不显著,不同发育时期反枝苋化感作用差异较为明显,其化感作用以幼苗期最强,现蕾期次之,成熟期最弱。推测化感作用是反枝苋发育初期取得竞争优势,迅速占领生态位的原因之一。

Root border cells（RBC） are cells surrounding the root apex.They are functionally different from the apex and are considered to play a role in the protection of the root tip from biotic and abiotic stresses.In order to explore the allelopathic mechanism of an alien invasive plant in China,Amaranthus retroflexus L（redroot pigweed）,allelopathic effects of the aqueous extracts from different development stages of this species on root border cells of cucumber were studied by aeroponic culture.The results showed that the aqueous extracts of A.retroflexus could stimulate the activity of pectin methylesterase of the root cap of cucumber,but the stimulating effect gradually lowered down along with the increasing concentration of the aqueous extracts,and the viability of root border cells decreased as the concentration of aqueous extracts increased.There were no significant differences among different organs of A.retroflexus at the same developmental stage,while significant differences were found in the A.retroflexus at different developmental stages and the order of strength of allelopathy at different developmental stages was seedling stageflower-bud stageripeness stage.These results suggested that allelopathy should be one of the reasons that A.retroflexus can compete with other species in the community and occupy niche in early developmental stages.