Effect of Echinocloa spp.Weeds on Yield of Rice and Their Physiological Mechanism in Mechanized Hill-Direct-Seeding Fields
To provide scientific basis on high yield of rice and integrated weed management,we carried out experiment in effect of Echinocloa spp.weeds on yield of rice and their physiological mechanism in mechanized hill-direct-seeding field.In this work,we taked Sujing 4699(a japonica cultivar)as a rice cultivar which was co-cultured with two Echinocloa weeds from 7 days after sowing to maturity of rice.And we also designed treatments as follow:rice with E.colonum(L.)Link,rice with E.crusgalli(L.)Beauv.var.mitis(Pursh)Petern,and weed free check(CK).The results showed that yield of rice co-cultured with Echinocloa weeds decreased significantly compared with CK,but differed largely between these two treatments.Due to the significant decrease in grain number per panicle,the rate of seed set and 1 000-grain weight,the yield of rice co-cultured with E.colonum(L.)Link decreased by 13.0％.The yield of rice co-cultured with E.crusgalli(L.)Beauv.var.mitis(Pursh)Petern reduced by 55.2％due to significant decrease in panicle number,grain number per panicle,the rate of seed set and 1 000-grain weight.When rice was co-cultured with E.colonum(L.)Link or E.crusgalli(L.)Beauv.var.mitis(Pursh)Petern,abscisic acid content in grains was significantly reduced at early grain filling stage.Oxidation activity of root,net photosynthetic rate of flag leaf,contents of zeat plus zeatinriboside in grains,activities of sucrose synthase,ADP glucose pyrophosphorylase,starch synthase and starch branching enzyme in grains also significantly decreased at rice grain filling stage.And aboveground dry matter accumulation significantly lessened at maturity stage.The decrease of the above-mentioned physiological indexes may be the important reason for the reduction of yield of rice co-cultured with Echinocloa spp.weeds under mechanized hill-direct-seeding.
rice in mechanized hill-direct-seeding fieldsEchinocloa spp.weedsyieldphysiological mechanism
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