| Object:Low temperature is a common abiotic stress in Xinjiang,which mostly occurs in early spring.Low temperature stress affect the growth and development of maize and the balance of physiological metabolism,and then negatively affect the yield of maize.The application of exogenous growth regulators to improve crop cold resistance is widely used in horticultural crops,but there are few reports on field crops.The purpose of this study is to explore the effect and physiological mechanism of growth regulators on alleviating chilling injury of Maize Seedlings under the background of low temperature chilling injury in early spring.On the basis of this study,further explore the combination of growth regulators and"starter fertilizer",improve the chilling resistance of maize seedlings and strengthen the effect of"starter fertilizer"on maize,so as to provide a new technical way for high-efficiency fertilization and increasing yield of maize production.Methods:The concentration and species of growth regulators were screened by seed germination test in the Oasis Ecological Laboratory of Shihezi University in 2017.Brassinolide(BR,0.01 mg·L-1,0.1mg·L-1,1 mg·L-1),diethyl aminoenthl hexanoate(DA,10 mg·L-1,20 mg·L-1,40 mg·L-1),naphthylacetic acid(NAA,0.1 mg·L-1,1 mg·L-1,4 mg·L-1)and citric acid(CA,0.01 mg·L-1,0.1mg·L-1,1 mg·L-1),comparing the germination rate,germination potential and vigor index of seeds under different treatments;pot experiment was used to test physiological effects of plant growth regulators on maize seedlings,which was carried out in the Experimental Station of College of agriculture,Shihezi University in 2018.DA(20 mg·L-1,30 mg·L-1,40 mg·L-1)and CA(0.2 mg·L-1,0.4 mg·L-1,0.6 mg·L-1)was used based on the screening experiment,the root system indexes and physiological characteristics of seedlings under different treatments were compared;the validation test of starter fertilizer formula was carried out in the 9th division of Xinjiang production and Construction Corps in 2019.The conventional fertilization（CF）,starter fertilizer（SF1）,starter fertilizer upgrading formula（SF2）application at gradient application were designed to study the root development characteristics of Maize Seedlings under starter fertilizer and analyze the effect of maize growth promoting and yield increasing effects.Results:（1）Growth regulators can alleviate the inhibition of low temperature stress on the germination of maize seeds with strong concentration effects.Under low temperature stress,the germination power,germination rate,germination index and vigor index of maize seeds treated with 20 mg·L-1DA,0.1mg·L-1CA were significantly higher than of control.At the same time,exogenous NAA treatment inhibited the germination of buds.Compared with root length and stem diameter,0.1 mg·L-1CA treatment was the best.（2）Applying optimum concentration of growth regulators can promote the synthesis of osmoregulation substances and improve the cold resistance of seedlings under low temperature stress.Under the condition of low temperature stress,0.2 mg·L-1CA showed best chlorophyll and proline content increase in the leaves of seedlings,and increase the root activity,reduce the relative conductivity and malondialdehyde content,and then alleviate the osmotic damage caused by low temperature stress.（3）Starter fertilizer promoted root number and root diameter,increase nutrient absorption of maize seedling.Citric acid compound starter fertilizer compared with the conventional control and starter fertilizer treatment,the yield of corn increased by 17.6% and 3.3%,and the economic benefit increased by 28.4% and 3.7%,respectively.Conclusions:Under low temperature conditions,0.1 mg·L-1 citric acid and 20 mg·L-1 diethyl aminoenthl hexanoate had the best effect on Seed germination and seedling growth.Exogenous growth regulators improve the chilling resistance of maize seedlings by promoting root growth and the synthesis of osmoregulation substances.The effects of different treatments on root activity,chlorophyll content,proline,malondialdehyde content and relative electrical conductivity of maize seedlings were compared.The chilling resistance of maize seedlings treated with citric acid was better than that with fresh amine ester,and the chilling resistance of maize seedlings with 0.2 mg·L-1 citric acid was the best.Citric acid combined with starter fertilizer can promote the development of maize seedling root,which is mainly reflected by the increase of root number and root diameter,and the increase of nutrient absorption of maize seedling.The growth regulator added to the starter fertilizer could further promote the growth of maize at seedling stage.The yield and economic benefit of citric acid combined with starter fertilizer increased by 3.3% and 3.7% respectively. |
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