Allelopathic effects and identification of allelochemicals in root exudates of grafted watermelons

Abstract：In order to study the allelopathic effects of root exudates from the watermelons grafted with pumpkin and calabash as rootstocks,effects of root exudates from the watermelons grafted on the seed germination and seedling growth of watermelons were researched.The Allelochemicals of root exudates were detected by GC-MS.The results showed that the seed germination and seedling growth of watermelons were increased when the root exudates were in low concentration,but decreased in high concentration.The root exudates promoted the seed germination and seedling growth of watermelons at 2.5 μL·L-1.The root exudates began to restrain the seed germination and seedling growth of watermelons at 10 μL·L-1.When the concentrations were lower,the root exudates from grafted watermelons had more effects on the seed germination and seedling vegetal promotion than own-rooted watermelons.The inhibiting effect of grafted watermelons was less than that of own-rooted watermelon at high concentration of root exudates.And the identification of the allelochemicals in root exudates of grafted watermelons indicated that the categories and the relative contents were different from the own-root plants.The results showed that grafting changed the categories and the relative contents of root exudate components and changed allelopathic effects.Furthermore,there was obvious grafting superiority.So grafting was one of the effective methods for relieving the continuous cropping obstacles caused by autotoxicity.