SNP Effect On Physiological Activity, Yield And Quality Of Different Potato Varieties Under Water Control

Drought stress is one of the most important limiting factors in environment during crop growth and different varieties of the same species have different responses to drought stress. Sodium Nitroprusside (SNP) is NO donor, it can induce plant defense responses. In this study potato cv. Atlantic and Dessiree with flower buds were sprayed by 0.01mmol L-1 SNP after drought stress. And then rehydration and dehydration circulated in pool which can prevent uncontrolled water inflow. The differences of physiological activity, yield and tuber quality between the two varieties and effect of SNP on them were studied. The results were as following:1. Under drought stress the stomatal conductance in leaves and H2O2 content of Atlantic was dramatically higher than that in Desiree, and its SPAD value, free proline, Malondialdehyde (MDA), as well as activities of invertase, POD, CAT and APX were dramatically lower than those in Desiree. After watering the stomatal conductance, SPAD value, Malondialdehyde content and APX activity in leaves of Atlantic were dramatically lower than those in Desiree, but its Super Anion content was opposite. Therefore, low stomatal conductance and H2O2 content, high SPAD value, free Proline and MDA, as well as high activities of invertase, POD, CAT and APX could be used as index for screening drought-resistant varieties. Meanwhile, stomatal conductance, super anion content and MDA were related to water content in soil, suggesting that they were associated with responses to drought stress in potato.2. Varieties with different drought resistance had different performances under the water control. Average yield per plant of Desiree was significantly lower than that of Atlantic, but tuber numbers per plant was significantly higher than that of Atlantic. The contents of phenylalanine,threonine,valine,leucine,iosleucine,lysine,glycine,serine,gutamine,asparagin e and pyroglutamic in Desiree were dramatically higher than those in Atlantic, and content of oxalate in Atlantic was higher than that in Desiree.3. Under drought stress spraying SNP improved drought tolerance, increased water content and SOD activity in leaves of Desiree and free proline and APX activity in Desiree and Atlantic, and decreased stomatal conductance and hydrogen peroxide content in both varieties. After watering spraying SNP significantly lowered stomatal conductance in Desiree and hydrogen peroxide content and SOD activity in both varieties, as well as POD activity in Atlantic. Meanwhile spraying SNP significantly increased CAT activity and SPAD value in Desiree, improved stomatal conductance, free proline and Super Anion (O2·) content in Atlantic, as well as invertase activity in both varieties.4 Under water control spraying SNP increased yield per plant in both varieties and tuber number per plant in Atlantic, and decreased tuber number in Desiree. Starch content in tuber of Desiree and sucrose content in Atlantic were decreased, and starch content in Atlantic and soluble sugar content and sucrose content in Desiree were dramatically increased with SNP spraying. Average yield per plant of Desiree was significantly lower than that of Atlantic, but tuber numbers per plant was significantly higher than that of Atlantic. The contents of 9 essential amino acids were improved in both varieties, and the contents of unessential amino acids were increased except aspartic acid in Desiree and asparaginate in Atlantic by SNP. The contents of citric acid,succinic acid,ascorbic acid,pyroglutamic acid,r-aminobutyric,oxaloacetic acid,oxoglutarate in Desiree and the contents of malic acid,citric acid,oxalate acid.succinic acid,ascorbid acid,r-aminobutyric acid,oxaloacetic acid and oxoglutarate in Atlantic were increased either by SNP.