Mitigative Effect Of Choline Choride On Drought Stressed Rapeseed At Seedling And Buding Stage

Rapeseed is the only winter oilseed crops in China, also is an important source of plant protein. In our country it is mainly distributed in around the Yangtze River. Although rainfall there is abundant, seasonal droughts occur frequently due to the uneven distribution of rainfall. Droughts do great harm to yield and quality of the rapeseed. cultivars of brassica napus Qinyou7and Suyou10were used to study the effect of drought stress on rape seedling physiological characteristics and yield as well as alleviated role of choline chloride on rapeseed with pot experiment, which would provide some theoretical basis and technical support for drought-resistant cultivation of rapeseed. The results showed as follows:Drought inhibited rapeseed plant height, the growth rate of stem diameter and biomass, and reduced relative water content (RWC) and chlorophyll content. Yield and yield components also decreased significantly. Certain concentration of choline chloride (CC) pretreatment alleviated the decrease of leaf relative water content and chlorophyll content. CC reduced plant height, but promoted the stem diameter and increased the ratio of root to shoot, biomass and yield.Drought induced reactive oxygen species (H2O2,HO·, O2-·), lipid peroxides MDA and antioxidants (GSH, AsA) content increased, while antioxidant enzymes (SOD, POD)activity first increased and then decreased. Choline chloride pretreatment increased SOD, POD activity and AsA content. CC also inhibited the accumulation of reactive oxygen species and MDA. It was more effective with drought sensitive varieties.Drought stress reduceed starch content, increased soluble sugar content, sucrose phosphate synthase and sucrose synthase activity. It also increased the glutamine synthetase activity and soluble protein content. Choline chloride pretreatment promoted the degradation of starch and improved the soluble sugar content of Qinyou7, especially fructose content; however, it reduced the soluble sugar content of suyou10. CC increased glutamine synthetase activity, and decreased soluble protein content and sucrose phosphate synthase and sucrose synthase activity of Qinyou7. But CC improved sucrose phosphate synthase activity of Suyou10.Compared the differences between cultivars, Qinyou7was less affected by drought. Alleviated effect of CC was more effective in cultivar of Suyou10.