Physiological Effects Of Relieving Rapeseed Waterlogging Stress By Strigolantones

Rapeseed is an important edible oil crop in the word.The main planting area of winter rape is distributed in the reaches of the Yangtze River in China.Because of the abundant rainfall in the area,the water is extremely vulnerable to waterlogging and can seriously affect the production of oil in autumn and spring.Herein,it is urgent to find strategies to alleviate the stress.Plant hormone is effective to regulate the plant growth.Strigolactone(SLs)is a newly found plant hormones,and can be effective in regulating plant branching ground and underground root system and production configuration.In this study,the pot experiment was carried out in one elite variety Zhongzhuang 11(ZS11),and the waterlogging treatment was carried out in rape five leaves stage.After 7 days,the waterlogging was carried out at 0 ?mol / L,0.1 ?mol / L,1 ?mol / L and 5 ?mol / L.waterlogging(W)and normal water group(C)were treated with root water(SLs).The effects of rape growth,photosynthesis,fluorescence reaction,chlorophyll content and the activity of antioxidant enzyme activity were studied.The main results are as follows:1.Effects of strigolactones on the growth of rapeseed.In the waterlogging experiment,the biomass of rapeseed increased with the increasing of the concentration of strigolactones,and the maximum weight of aboveground was observed with the concentration of 5?mol/L,And the biomass increase the most significantly when the concentration of strigolactones was 5?mol/L compared with control.strigolactones can improve the relative water content and leaf area of rapeseed leaves.At the same time,strigolactones can effectively promote the rootgrowth,inclulding the increase of total root length,root area,root mean diameter and apical number.2.Effects of strigolactones on photosynthesis and chlorophyll fluorescence of rapeseed.leaf photosynthesis decreased significantly under waterlogging compared to the normal conditions.However,when the concentration of strigolactones was 1 ?mol/L,strigolactones application significantly increased chlorophyll content(including chlorophyll a and chlorophyll b)and carotenoid content.While strigolactones increase the net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)in the leaves,decreased cell between CO2 concentration(Ci).Strigolactones also increases the relative electron transfer efficiency of the transfer(rETR),PS ? maximum energy conversion efficiency(Fv/Fm),PS ? potential activity(Fv/Fo),and strigolactones also improved PS? effective photochemical efficiency(Fv'/Fm')and the actual energy conversion efficiency PS?(?PS?)in the leaves on aboveground,whereas reduces non-photochemical quenching(qN);from the point of biochemical.3.Effects of strigolactones on activity of antioxidant enzymes.The results showed that when the concentration of strigolactones was 1 ?mol/L,the activity of superoxide dismutase in waterlogged rapeseed decreased slightly,and the activities of catalase and peroxidase were increased.The contents of proline and soluble protein were improved.At the same time,it increased the membrane lipid peroxidation content,which made a very good effect on protecting the cells.