Regulation Of Diethyl Aminoethyl Hexanoate, Thidiazuron And Their Combinations On Soybean Growth And Mechanism Of Carbon Metabolism

As an important dual-purpose crop of"grain,oil and feed"in the world,soybean does not contain cholesterol,and it has become an important source of high-quality protein,edible oil and animal feed for human beings.Therefore,soybean has been closely watched by countries all over the world.In recent years,with the improvement of people’s living standards and changes in dietary structure,China’s demand for foreign soybeans has been increasing day by day.According to statistics,China will import nearly 96 million tons of soybeans from abroad in2021-2022.The main reason for this phenomenon is that there is still a gap between the average yield level of soybeans in our country and the world average level,and the quality advantage is not outstanding.As a result,the economic benefits are low,the enthusiasm of agricultural producers is difficult to mobilize,and the planting area is difficult to increase.The value cannot fully meet the actual production needs of Chinese people.Therefore,increasing production and improving quality is still an important issue to be solved urgently in our country’s soybean agricultural production.Plant growth regulators play a vital role in crop growth and development and can be used to achieve this goal.Therefore,Kennong 18（K18）,Dongnongdou 252（D252）and Dengke 4（DK4）)were used as test materials in this experiment,and the method of barrel planting combined with field spraying was carried out at the R1 stage,to explore the regulation of different plant growth regulators and their combinations on soybean growth and mechanism of carbon metabolism.The main test results are as follows:（1）The single agent screening test found that the five common plant growth regulators have different degrees of regulatory effect on soybean growth,compared with brassinolide,prohexadione-calcium and 6-benzylaminopurine,foliar spraying of diethyl aminoethyl hexanoate and thidiazuron had a more comprehensive and effective promotion effect,both agents significantly increased the chlorophyll content of soybeans,enhanced photosynthesis,promote the metabolism of the main carbohydrates in the leaves,which in turn increased the height of soybean plants,stem diameter and above-ground dry matter accumulation,to achieve the purpose of increasing yields,and the residue detection of each agent in the seeds in line with national standards.（2）Foliar spraying of diethyl aminoethyl hexanoate,thidiazuron and their combinations effectively promoted the chlorophyll content of soybean leaves,which in turn led to enhanced photosynthetic and fluorescence responses,and the effect of the combinations was better than that of the single agent.The process significantly promoted the electron transfer efficiency of soybean leaves,resulting in the increase of light energy conversion efficiency and the actual photochemical efficiency of photosystem II.The stomatal conductance was significantly increased,which facilitated the entry of CO₂into the plant for gas exchange,resulting in the increase of intercellular CO₂concentration,which in turn increased the net photosynthetic rate of soybean and finally enhanced photosynthetic and carbon assimilation capacity,improving soybean plant height,stem diameter and aboveground dry matter accumulation.（3）Foliar spraying of diethyl aminoethyl hexanoate,thidiazuron and their combinations significantly increased the activities of enzymes related to carbon metabolism in soybean.The increased activities of sucrose phosphate synthase and sucrose synthase increased sucrose and starch contents,which in turn effectively improved the progress of source-sink transport;the increased activities of sucrose convertase facilitated the interconversion of carbohydrates in the leaves,which in turn improved the carbohydrate transport capacity;the increased activities of amylase promoted starch degradation to a certain extent,and multiple enzymes cooperated to improve the synthesis,transport and accumulation of carbohydrates in the leaves and accumulation capacity in the leaves.（4）Foliar spraying of diethyl aminoethyl hexanoate,thidiazuron and their combinations effectively improve the yield and quality of the three varieties of soybeans.The 40 mg·L^-1diethyl diethylethyl hexanoate and 0.2 mg·L^-1thidiazuron treatments have a significant advantage in promoting the grain weight per plant,with a maximum increase of 45.24%.There are differences in the effects of compound treatments due to different varieties,and the effect of a single agent is better than that of the combinations.The combinations of 60 mg·L^-1diethyl aminoethyl hexanoate with 0.6mg·L^-1thidiazuron was beneficial to quality improvementt,with a maximum increase of fat of 7.78%and a maximum increase of protein of 6.20%.In summary,the results of this experiment showed that diethyl aminoethyl hexanoate,thidiazuron and their combinations can effectively regulate soybean growth,specifically by promoting plant height,stem diameter and aboveground dry matter accumulation,increasing leaves chlorophyll content,enhancing chlorophyll fluorescence and photosynthetic capacity,regulating leaves carbon metabolism-related enzyme activities,increasing leaf carbohydrate content,and then accelerating the rate of organic matter transfer from leaves to seeds,and finally achieving the purpose of improving soybean quality and yield.