Study On The Effect Of Interaction Of Plant Growth Regulations And Herbicides On The Physiology And Biochemistry Of Solanum Nigrum L.

Black nightshade (Solanum nigrum L.) is one of most problem weeds that troubled the cultivation ofcotton and other crops, and is treated by single or complex herbicides used for soil or foliar treatments inthe past. In this paper, the effect of Gibberellic acid(GA3) and Mepiquat chloride(DPC) combination withherbicides on the fresh weight, plant height, chlorophyll content, soluble protein content, MDA content andantioxidant enzymes activity of black nightshade and cotton were determined to explore new approach ofmixture chemical for weeds control and cotton security, aiming at providing effective agents for controllingblack nightshade and theoretical basis for the mixture of plant growth regulator and herbicides.The results showed that: the control efficiency of glyphosate, fluroxypyr, bentazone and prometryn onblack nightshade were100%recorded at9days after application, and the inhibition rate of biomass wasmore than70%. The effect of Tribenuron and trifloxysulfuron on black nightshade was slow and justreached90.72%and88.75%, respectively, at9days after application. The control efficiency of bensulfuronand pyrazosulfuron were not obvious and partial discoloration of black nightshade leaves were found aftertreated by these herbicides.The pot experiments were conducted to study the effect of GA3and DPC on glyphosate, prometrynand trifloxysulfuron in controlling of black nightshade. The results showed that: glyphosate combinationwith GA3could increase the biomass inhibition rate of black nightshade. The fresh weight inhibition ofblack nightshade treated by prometryn combination with GA3was higher than ones treated by prometrynalone. Trifloxysulfuron combination with DPC could increase the biomass inhibition of black nightshade.Although the biomass inhibition of black nightshade treated by3kinds of herbicides combination withGA3or DPC were different.the chlorophyll and soluble protein content and antioxidant enzyme activity ofblack nightshade treated by glyphosate, prometryn and trifloxysulfuron combination with GA3were lower,and their MDA content was higher indicating that the combination of GA3and herbicides could reduce thetolerance of black nightshade to herbicides and enhance control effect,and have great potential in weedcontrol.The result of pot and field experiments show that: in seeding stage, bud stage and flower bud stage,compared to the cotton treated with glyphosate or prometryn alone, the lower chlorophyll content, solublecontent, POD activity，CAT activities and higher MDA content, SOD activity of ones treated withglyphosate or prometryn in combination with GA3indicated the combination of GA3and glyphosate orprometryn done more injure to cotton. Compared to the cotton treated with trifloxysulfuron alon, the lowerMDA content and higher soluble protein content, POD and CAT activities of ones treated withtrifloxysulfuron in combination with GA3indicated that the combination of GA3and trifloxysulfuroncould reduce injury to cotton. When combined with herbicides, the effect of DPC on the physiology andbiochemistry of cotton was opposite to GA3.