The Interaction Of Exogenous Salicylic Acid And Chitosan In Inducing Resistance Of Cucumber Seedlings To Salt Stress

Soil salinification seriouly influence the development of vegetables facility cultivation. The research indicated that the salicylic acid and chitosan may induce salt resistance of the plant. But no report about the interaction of exogenous salicylic acid and chitosan in inducing resistance of cucumber seedlings to salt stress. This research take the cucumber as experiments material, studied the effect of extraneous salicylic acid and chitosan to the cucumber seed germination, seedling growth and physio-biochemical index under the salt stress. For the purpose of discussing the mechanism of interaction in inducing resistance of cucumber seedlings to salt stress.With the method of soaking seeds, study the influence of salicylic acid and chitosan to the cucumber seed germination and the vigor index.The research indicated that during seed germination, the salicylic acid and the chitosan relieve the reduction of biological oxidation and the breath related enzyme that cause by salt stress.Therefore, the root length, the lateral root number, the embrionic axial length, the germination percentage, the germination tendency, the germinates index and the vitality index extremely is remarkable higher than the salt stress. SA and CTS have obviously synergistic effect to the acid phosphatase, amylase and dehydrogenase activeness and the germination percentage, the vitality index, hypocotyl length.With hydroponics, study the influence of salicylic acid and chitosan to the physio-biochemical index of cucumber seeding. Under the salt stress, the active oxygen metabolism dynamical equilibrium is broken, the content of active oxygen elevates, the oxidation resistance enzyme activity reduces and causes the peroxidation to membrane, cell electrolyte exosmosis.The salt stress causes the chloroplast membrane disintegration, the chlorophyll content and root vigor reduce. At initial period, SA induction seedling's oxidation resistance enzyme activity ascend except for CAT and APX , the enzyme POD,SOD activity is obviously higher than the salt stress . Enzyme activity elevated has suppressed the increase of active oxygen content, reduced the injury that excessive active oxygen to the cell membrane, the membrane peroxidation and the electrolyte exosmosis reduces, that guaranteed the cell membrane integrity. Plant physiology activeness is higher than salt stress. SA and CTS have the interactive effect to enzyme SOD and POD, production speed of the O2-, the electrolyte leakage, the MDA content, that is interaction's effect is bigger than the sole induction effect.Study the effect of SA and CTS to soluble proteins by Coomassie Brilliant Blue G-250 and SDS-PAGE. Under the salt stress the concentration of protein in cucumber seedling root and leaf elevates compared to the comparison, is obviously higher in the 3rd day than the clear water comparison. With the time pass by the concentration reduce, especially the 61.5,47 and 43kD. After SA or CTS induction the root system soluble protein's concentration (3~6d) is lower than the salt stress in the stress period, in 9d the concentration is higher than the salt stress. The SA and CTS have obviously synergistic effect to the concentration of protein in cucumber seedling.Study the effect of SA and CTS to the photosynthesis by photosynthetic apparatus, the result indicate that salt stress causes the photosynthesis speed, stomatal conductance, the concentration of carbon dioxide among cells, the transpiration rate reduce. The plant growth suppresses highly, the stem, the dry matter accumulates is lower than the comparison. The SA and CTS make the interactive effect on photosynthesis speed, stomatal conductance and the transpiration rate.Use the method of preprocessing by Ca2+ and Ca2+ inhibitors (EGTA, La3+, RR) to study the effect of Ca2+ during SA and CTS in inducing the resistance to salt stress. The result indicate during the process of inducing salt resistance, Ca2+ can increase the salt resistance and can raise the effect of SA and CTS.Ca2+ inhibitor has suppressed the function of SA and CTS. And the EGTA effect is most obvious, soaks seeds processing after EGTA, regardless of being SA or CTS induces its active oxygen content remarkable bigger than SA and CTS affects alone.The result means during the inducing process Ca2+ paly a importanct role.