嫁接西瓜根系分泌物的化感效应及其化感物质的鉴定

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

为了研究嫁接西瓜根系分泌物的化感效应,采用南瓜、葫芦作砧木嫁接西瓜,研究了嫁接西瓜根系分泌物对西瓜种子萌发和幼苗生长的影响,并对嫁接西瓜根系分泌物中的化感物质进行了GC-MS检测。结果表明,各处理对西瓜种子发芽和幼苗生长均呈现出低促高抑的规律。在根系分泌物浓缩液浓度为2.5μL.L-1时,促进西瓜种子的发芽和幼苗的生长。在浓度为10μL.L-1、20μL.L-1时,表现为抑制作用。低浓度时,嫁接西瓜根系分泌物对西瓜种子发芽和幼苗生长的促进作用大于西瓜自根苗。高浓度时,抑制作用弱于西瓜自根苗。嫁接西瓜根系分泌物中化感物质的种类和相对含量与西瓜自根苗相比均有变化,表现为某些物质相对含量增加、特异性物质出现以及相对含量减少或消失。说明嫁接改变了西瓜根系分泌物中化学物质的种类和相对含量,改变了西瓜根系分泌物的化感效应,表现出嫁接优势。

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.