Allelopathic Potential of Polygonum orientale L. in Relation to Germination and Seedling Growth of Weeds

Abstract

The activity of the leaf-extract, leaf-leachate and decaying leaves of Polygonum orientale as well as the leaf-litter from below Polygonum plants has been examined in terms of the inhibition of the seed germination and the root and hypocotyl growth of five different weeds like Amaranthus spinosus , Cassia sophera , C. tora , Evolvulus nummularius and Tephrosia hamiltonii . Although the leaf-extract and leaf-leachate are equally effective, phytotoxicity increases in the order: leaf-extract/leaf-leachate > decaying leaves > field soils. Of the weeds, C. sophera seems to be uniformly affected by the inhibiting material. Since Polygonum leaves constitute the source of inhibitors, the leaves are chemically analysed and the presence of flavones in them has been implicated in allelopathy.