Regulatory Effects Of Exogenous Substances On Physiological Characteristics And Yield Formation Of Chemically Capped Cotton

Chemical regulation technology is an effective way to increase crop yield and has been widely used in agricultural production.In order to ascertain the effects of different exogenous substances on the agronomic traits,physiological characteristics and yield formation of chemically capped cotton,provide scientific basis for the application of foreign materials.The test was carried out at the Sanping Farm Test Base of Xinjiang Agricultural University,Xinluzao 57,which was widely planted in northern Xinjiang,was used as experimental material,three doses(low,medium and high)were set,and four kinds of exogenous substances were used to chemically cap the cotton leaf spray,methyl caprylate,brassinolide,compound sodium nitrophenolate,naphthaleneacetic acid and clear water were used as control.The effects of exogenous substances on agronomic traits,antioxidant enzyme activities,osmotic adjustment ability,photosynthetic characteristics and yield formation of chemically capped cotton were studied.Comprehensive analysis and evaluation of the changes in the indicators,Screening out the most effective exogenous substance and its dosage,it provides a reference for further improving and improving cotton chemical control technology in cotton production.The main conclusions are as follows:1.Effects of exogenous substances on protective enzyme activity and osmotic adjustment ability of chemically capped cotton leavesFour different doses of exogenous substances can significantly increase superoxide dismutase(SOD),peroxidase(POD)activity,soluble protein(SP),soluble sugar(SS)content and reduce malondialdehyde in cotton leaves.(MDA)content.Among them,the regulation effects on soluble protein,soluble sugar and MDA were compound sodium nitrophenolate>methyl caprylate>naphthaleneacetic acid>brassinolide.The activity of SOD and POD was regulated by brassinolide>methyl caprylate>compound sodium nitrophenolate>naphthaleneacetic acid.The optimal dosage of methyl caprylate was 75 mL/hm2,brassinolide was 15 mL/hm2,compound sodium nitrophenolate was 7.5 mL/hm2,and naphthaleneacetic acid was 3 mL/hm2.2.Effects of exogenous substances on photosynthetic characteristics of chemically capped cotton leavesFour different doses of exogenous substances have a certain regulation effect on the photosynthetic characteristics of cotton leaves.With the increase of the dosage of exogenous substances,besides transpiration rate(Tr),the gas exchange parameters such as leaf area index(LAL),chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci)of cotton increased first and then decreased.Compared with CK,at 10 days after spraying,chlorophyll content and net photosynthetic rate of 75 mL/hm2 methyl caprylate treatment were the highest,the maximum net photosynthetic rate was40.97 μmol·m-2·s-1.At three doses,the leaf area index(LAI)of T4 treatment decreased rapidly with the increase of T4 dosage.3.Effects of exogenous substances on agronomic traits and yield formation of chemically capped cottonFour different doses of exogenous substances have obvious dose effects on cotton agronomic traits and yield formation indicators.After spraying various exogenous substances,the number of bolls per plant,single boll weight,clothing score and yield increase were higher than other doses,among them,under 75 mL/hm2 methyl caprylate,150 mL/hm2 methyl caprylate,7.5 mL/hm2 compound sodium nitrophenolate and 15 mL/hm2 brassinolide,cotton biomass and seed cotton yield increased.Among them,75mL/hm2 methyl caprylate had the best effect,which increased the yield of seed cotton by 25.88%compared with the control.7.5 mL/hm2 compound sodium nitrophenolate and 15 mL/hm2 brassinosteroid followed.