Physiological And Photosynthetic Response Of Soybean Under Drought Stress In Flowering Period

Soybean has a high nutritional value,is the world's highest yield oil crops,but also rich in plant protein,to provide human and animals with the necessary edible oil,protein feed.Due to the lack of water resources in the north of China,drought has become the main factor limiting the yield and quality of soybean.Therefore,the research on the physiology of soybean drought resistant cultivation has become one of the key points in soybean production.The experiment was carried out in the glass rainproof shed of Northeast Agricultural University from 201 8 to 2019.Taking Heinong 84 and Hefeng 46 as the test varieties,they were planted in the state of Chernozem,Albic Soil and black soil,and treated with drought stress at the flowering stage when soybean is most sensitive to water,to explore the effects of drought stress on membrane lipid peroxidation,key antioxidant enzyme activities,key enzyme activities of carbon and nitrogen metabolism and photosynthetic characteristics of soybean Influence.The aim is to provide theoretical basis and lay a foundation for soybean drought resistant physiological cultivation and variety selection.The main results are as follows:(1)With the increase of drought stress,the proline content of soybean leaves increased first and then decreased,reaching the maximum in moderate drought;the relative conductivity and malondialdehyde content of soybean leaves increased continuously,reaching the maximum under severe drought stress;the relative water content of soybean leaves gradually decreased,reaching the minimum under severe drought stress.Under moderate and severe drought,the contents of pro,relative water content and malondialdehyde in soybean leaves were albic soil > chernozem > chernozem,and the relative conductivity of soybean leaves was albic soil > chernozem > chernozem.The regularity of the two varieties was the same.(2)The activity of SOD and pod in soybean leaves increased first and then decreased under drought stress,and the highest was in moderate drought;the activity of GR and GPX in soybean leaves increased gradually,and the highest was in severe drought.Under drought stress,the activity of SOD enzyme in soybean leaves was black soil > chernozem > albic soil;the activity of pod and GR enzyme was white soil > chernozem > black soil,and the activity of GPX enzyme was chernozem > black soil > albic soil.The two varieties showed the same performance.(3)The activities of SS-1,6pgdh and G6 PDH in soybean leaves increased first and then decreased under drought stress.The activities of SS-1,6pgdh and G6 PDH were the highest under moderate drought stress,and the two varieties showed the same trend.The activity of SS-1 and G6 PDH was white soil > chernozem > black soil.The enzyme activity of 6pgdh was as follows : chernozem > albic soil > chernozem.The law of varieties is the same.(4)With the increase of drought stress,the activity of NR enzyme in leaves decreased gradually,and reached the minimum in severe drought;the activity of GS enzyme and GOGAT enzyme in soybean leaves increased first and then decreased,and the highest in moderate drought.Under moderate drought stress,NR enzyme activity was in black soil > albic soil > chernozem,and GS enzyme and GOGAT enzyme activity in soybean leaves were in white soil > chernozem > chernozem.(5)Drought stress increased the relative chlorophyll content of soybean leaves,which reached the highest level in severe drought,and the two varieties showed the same performance;under severe drought,the performance of heinong84 was significantly higher than that of Chernozem and albic soil,and hefeng46 had significant differences among the three soils.Under drought stress,phi2 and Phino increased gradually,and severe drought reached the maximum,and the increasing range was larger and larger.Severe drought was significantly high er than the other three water states,and the two varieties showed the same performance.The phinpq of soybean leaves decreased gradually and reached the lowest under severe drought stress.(6)With the increase of drought stress,the F0 and FS of soybean leaves showed a single peak curve,and the maximum was in moderate drought;the trend of FM and Fv / FM of soybean leaves increased gradually,and the maximum was in severe drought.Under drought stress,there was no significant difference between F0 chernozem,Albic Soil and chernozem;in moderate and severe drought,the performance of FM was significantly higher than that of Albic Soil and chernozem;NPQ of soybean leaves was significantly lower than that of Albic Soil and chernozem.There are some differences among varieties.