The Influence Of Exogenous Nitric Oxide To Daucus Carota Under Saline Alkali Stress Of NaCl Simulation On Seeds Generation And The Content Of Some Physiological Substances

The disadvantages of continuous cropping in greenhouse is widely presented,such as destruction of soil physical structure and salt accumulation.All this has become a bottleneck for the further development of greenhouse cultivation.Previous studies have shown that low concentrations of nitric oxide?NO?has a good role in mitigation to stress.Daucus carota L.as test materials in this experiment,and through the study of different concentrations of NO donor sodium nitroprusside influence on the germination effect of purple carrot seeds and physiological substance content under salt stress,we draw the following conclusions.The influence of sodium nitroprussiate with different concentrations on seeds generation of Daucus carota under saline alkali stress simulated by NaCl.The result showed that: under NaCl simulated saline alkali stress,the seed generation rate of Daucus carota decreased,and the growth of radicle was inhibited at the same time.Stimulation and inhibition function were found in seeds treated with low and high concentrated sodium nitroprussiate: when the concentration is between 0.05⁰.4mmol·L^-1,the inhibition of saline alkali stress decreased,while when the concentration was higher than 0.7 mmol·L^-1,it even aggravate inhibition of the stress.When under saline alkali stress,the best concentration of sodium nitroprussiate for seed generation is 0.1 mmol·L^-1.The influence of sodium nitroprusside?NO donor?with different concentrations treatment on dry matter content?dry weight / fresh weight?about aboveground and underground part of Daucus carota seedlings while under NaCl stress.The result showed that,the best concentration of sodium nitroprusside is 0.1 mmol·L^-1,the rate of dry matter was significantly lower than other concentrations,and extremely significantly lower than the separate treatment of NaCl(concentration is 100mmol·L^-1).The dry weight of seedlings were decreased when the concentration of sodium nitroprusside was higher than 0.9 mmol·L^-1.3.The influence of sodium nitroprusside?NO donor?with different concentrations treatment on enzymatic activity of SOD,POD,CAT of Daucus carota seedlings leaves.The result showed that,SOD activity was decreased when under NaCl stress.Sodium nitroprusside have a dual action on enzymatic activity of SOD,POD,CAT.Low concentration(0.05⁰.6 mmol·L^-1)can significantly improved the activities of the three enzymes,among them the enzymatic activity improved mostwhen the concentration of sodium nitroprusside is 0.1 mmol·L^-1.While high concentration(more than 0.6 mmol·L^-1)played an inhibitory effect on enzymatic activity.So we can better alleviate the membrane lipid peroxidation caused by NaCl stress,improved the ability of osmotic adjustment,and maintained the stable of carbon and nitrogen metabolism.4.The influence of sodium nitroprusside?NO donor?with different concentrations treatment on leaves chlorophyll content during the growing season of purple carrot's fleshy roots.The result showed that,the content of leaves chlorophyll which treated by NaCl with 100 mmol·L^-1 concentrations was significantly lower than CK.The chlorophyll content which treated by different concentration gradients were higher than treated by NaCl alone,the best concentration of sodium nitroprussiate is0.1 mmol·L^-1.5.The influence of sodium nitroprusside with different concentrations on the three kinds of natural active substances?carotenoid,anthocyanin,chlorophyll a and chlorophyll b?about the mature season of purple carrot's fleshy roots under salt stress simulated by NaCl.The result showed that,the content of the three kinds of natural active substances in purple carrot's fleshy roots were decreased with salt stress,the content of the three kinds of natural active substances which treated by the sodium nitroprusside have a increase trend than those treated by NaCl alone.The degree of the improvement about the content of the three kinds of natural active substances showed a increase and then decrease trend with the changes in the concentration of sodium nitroprusside,the content of the three kinds of natural active substances have a most significant rate of increase when the concentration of sodium nitroprusside is0.1 mmol·L^-1.6.The influence of sodium nitroprusside with different concentrations on net photosynthetic efficiency and chlorophyll fluorescence of purple carrot's leaves during different seasons under salt stress simulated by NaCl.The result showed that,the Pn and Gs decreased,while Ci and Tr increased significantly under salt stress simulated by NaCl.Under low concentration of SNP,Pn and Gs were increased,while Ci and Tr decreased in different degree,but a high concentration of SNP have the opposite effect.0.1 mmol·L^-1 SNP had the best mitigation effect to salt stress.The Fv/Fm,?PSII and qP decreased while qN increased significantly under salt stress.The low concentration of SNP can increase the Fv/Fm,?PSII and qP effectively,also can decrease the qN significantly.The high concentration ofSNP have the opposite effect.0.1 mmol·L^-1 SNP had the best mitigation effect to salt stress.