Effects Of Salt And Drought Stesses On Camelina Seedling Physiology And Test Of Variety

Camelina has some unique argonomic advantages: high oil content, short growing season(85-100 days), low agricultural inputs, insect and weed tolerance, and strong abiotic stress tolerances, especially drought tolerance. Owing to specific fatty acid composition and some fuel properties superior to other bio-oils, camelina will potentially serve as a low-input alternative oil source for advanced biofuels. In recent years, the cultivation area of camelina has been continuously expanding. However, the crop has not yet been effective introduced and cultured in northwest China. All these merits make camelina suitable to culture in the arid area of northwest district in China, which brings not only economic benefits, but also environment benefits. Understanding the response mechanisms of camelina under drought and salt stresses is helpful to evaluate stress resistance of cultivars, but there has been no report.The aim of this study is to investigate mechanism of drought resistance of camelina seedlings, and meanwhile, to evaluate drought resistance of different cultivars by the statistical method of Grey relational analysis(GRA). Also, another goal of this study is to investigate the dynamic of several physical and biochemical indexes under salt stress. Main results are as follows.1. The changes of several physiological characteristics of seven camelina cultivars were compared under drought stress. The level of superoxide(O2-) production, activities of malonaldehyde molality(MDA), superoxide dismutase activity(SOD), peroxidase activity(POD) and catalase activity(CAT) increased and total soluble protein content decreased under drought stress. Almost all the indexes were well consistent among different varieties, except POD. Results of GRA showed that the correlation of plant drought resistance and physiological indexes from strong to weak was SOD, CAT, O2-, MDA, Soluble, POD, and the drought tolerance order from strong to weak of all cultivars was Celine, Chegenne, Yellow Stone, MT-1, Som, Suneson and Ligena. According to the survey of agronomic traits, Celine had advantage in total pods, per plant yield, lodging and yield over other cultivars. Combining the strongest drought resistance, Celine is the best among the seven cultuivars for northwest China.2. Salt stress seriously affected plant growth and hindered water uptake, which resulted in the gradual decline of relative water content(RWC) along with the increase of salt density. Parameters of membrane damage showed changes under salt stress, including membrane permeability and membrane lipid peroxidation. The levels of relative electric conductivity and MDA gradually increased along with the increase of salt density. But the further increase of the salt density led to decrease of MDA, showing that there temporal restriction to evaluate the salt resistance according to the changes of MDA contents. Salt stress caused the accumulation of reactive oxygen, and meanwhile, it also activated the free radical scavenging system. Peak values of enzyme activities appeared one another in sequence of SOD, POD and CAT. But the activity of three antioxidant enzymes reduced under high-salt stress, showing that these parameters depend on the salt concentrations and duration of treatments. Combining the results of salt-tolerance experiments, camelina leaves showed faster response under the salt stress and they could respond quickly. Cells(especially root cells) rehydrated from high salt concentration recovered slowly from the state of being stressed.