Effects Of DDTC Under Waterlogging At Seedling Stage Of Soybean On Physiological Characteristics,Yield And Quality At Maturation Stage

The soybean is one of important oil crops in china,an important source of high quality protein and human edible oils and fats.Soybean is a kind of dryland crop and is more sensitivity to waterlogging.As rainfall in South China much and concentrated,the waterlogging stress occurs easier in the process of the growth of soyben,which causing economic losses.Therefore how to alleviate the effects of waterlogging disaster on yield and quality on soybean,has become an urgent problem that need to be solved.In this study,one pot experiment was taken that soybean(Glycine max var.Nannong99-6)and diethyldithicarbamate(DDTC)was used to study the effects of DDTC on alleviating tne harm of waterlogging stress and physiological mechanism.In order to clarify the use of DDTC,pre sparying DDTC and spraying after waterlogging stress removed were compared,which provided throretical basis of soybean waterlogging resistance and disaster reduction.The result is ad follows:1.The content of H2O2,MDA,the rate of O2-·production in leaves is increased under waterlogging stress,and the degree of membrane lipid peroxidation is deeper as waterlogging stress time lasted.The levels of antioxidant enzymes and substances was improved,the antioxidant capacity of soybean is stronger,but it not enough to offset the damage caused by waterlogging stress.Pre spraying DDTC can alleviate the oxidative damage of waterlogging on plants,the content of ROS and MDA were decreased,so there is a little change of the antioxidant system.It is found in ASA-GSH cycle that:pre soraying DDTC can promoted the accumulation of ASA and the consumption of GSH,the active oxygen is cleaned and soybean get stronger adaptability.Sparying DDTC after waterlogging stress removed consume active oxygen by improving the activity of POD,APX,GPX in leaves of soybean and regeneration of ASA and GSH.2.Waterlogging stress leads the degradation of chlorophyll.The activity of amylase improved,the content of starch decreased,and carbohydrates in leaves transhipped to the root,cause the content of soluble decreased in leaves,the content of soluble increased in root,and the activity of enzymes related sucrose metabolism improved.The result is carbohydrate metabolism out of balance.The activity of SPS,SS and INV were improved for increasing sucrose content and decreasing hydrolysis of sucrose and starch.The results are cell osmoregulation ability enhanced,transportation and distribution of photosyntnate ability enhanced,therefore leaves providing more products for sink organs.3.The biomass was significantly decreased under waterlogging stress,causing a decreasing of the yield.Tne content of protein decreased in grain,the content of starch and fat were increased in grain.Spraying DDTC could alleviate the decline of protein,and the rise of starch and fat.While spraing DDTC after waterlogging stress removed is better for increasing compensatory growth,causing yield is higher than pre spraying DDTC,at the same time,the quality is better than pre spraying DDTC.4.Through the comparison of two methods,spraying DDTC after stress removed is bettter for the antioxidant level,biomass accumulation.The drop of the final yield and quality is minimum.So spraying DDTC after stress removed is better on production.