Alleviative Effects Of Triadimefon Long-term Drought Stress In Soybean Flowering Stage

Soybean(Glycine max[L.]Merr.)has wide earth foundation range in our country and it is a significant source of high quality protein and plant oil.Drought was one of the most common adversity stress and had a strong impact on crop growth and yield.Soybean had sensitivity to humidity,especially at the flowering stage and the podding stage.Drought stress can give rise to cause low yield.So how to alleviate drought stress effect and remit drought damage become the key problem to be solved.At present,applying growth regulators is an important method to enhance soybean drought resistance.Triadimefon as one kind of growth regulators,it can inhibit overground and promote underground and has an effect on plant growth.In this paper,we selected Nannong 99-6 as raw material and studied the effects of long-time drought on soybean growth,physiological properties and quality and its inner mechanism with simulation of drought with pot experiment.Meanwhile we studied under drought stress the effects of extraneous TDM on soybean growth,physiological properties and qualityin the flower period.So as to elucidate the triadimefon mechanism for alleviating soybean drought stress in the flower period.In offer application of theoretical and technical support for the soybean drought resistant cultivation.1.Drought stress significantly depressed the growth and yield of soybean,promoting cell death in root..However,drought-stressed plants treated with TDM showed much higher biomass,SPAD,specific leaf weight and yield than those without TDM.TDM make the soybean plant more short.It also prevent the progress of root cell death,promoted growth and development of root system,changed root anatomy and improved water holding capacity.When extraneous TDM increased leaf SPAD,it also significantaly prolonged green period and increased number of pods and seeds per plant and improved the grain weight per plant.2.Drought stress significantly inhibited photosynthesis of soybean,changed the balance of carbon metabolism in leaves,improved the capacity of osmotic regulation.TDM made the downtrend of Gs、Tr、Pn and chlorophyll content in soybean leaves under drought stress well mitigated,inhibited the rise of Ci and also improved the activity of RUBPCase,reduced photosynthetic system damage caused by drought.Under drought stress,exogenous TDM also improved the activity of SPS、SS in synthesis direction and restrained SS in direction of cleavage and the rise of INV、FBP and a-amylolytic enzyme activity.And also increased starch contents in leaves and inhibited the rise of sugar contents and reduced the supression of sugar over-accumulation in source leaf to photosynthetic.TDM promoted transport of sucrose contents to root part and increased sucrose contents and starch contents in root part.And it also improved root osmotic adjustment to promote its growth and development.3.Drought stress induced Accumulation of ROS in leaves,Stimulated antioxidant system of leaves to eliminate ROS.TDM significantly improved the activity of SOD、POD and CAT,increased AsAand GSH content,suspended the decrease of APX、MDHAR、Grand GPX activity in late drought stage,so reduced MDA、H2O2 content in soybean leaves and the production rate of O2-,alleviated the harmness to soybean caused by ROS accumulation which due to the peroxidization of cytomembrane caused by drought,thus improved drought resistance of soybean.In conclusion,drought stress inhibited the growth of soybean greatly,inhibited photosynthesis,enhanced enzyme activities involved in carbon metabolism,sped up catabolism so as to maintain the normal osmotic regulation;drought stress also caused the peroxidization of cytomembrane,stimulated antioxidant system to inhance the ability of scavenge ROS.Spraying TDM inhibited longitudinal growth of soybean and promoted cross growth and root development,increaseed water use efficiency,alleviated the effect on photosynthesis induced by drought stress,modulated enzyme activities involved in carbon metabolism,alleviated the photosynthetic feedback inhibition induced by over-accumulation of photosynthate,promoted more sucrose transported down to meet the need of root,improved the capacity of osmotic regulation of roots;at the same time increased antioxidant ability of soybean,thereby the drought resistance enhanced.