Researches Of Exogenous Nitric Oxide Regulation On Medicago Sativa Germination And Cold Tolerance Under Imbibitional Chilling

Mainly by using incubation culture methodology and combined with the methodolycurrently applied in the research fieids of Plant Physiology, Bio-chemietry, started withsystematic analysis of plant biology and physiological on4℃imbibitional chilling, studieson regulation of exogenous nitric oxide (SNP) on seeds germination, physiologicalcharacteristics and antioxide ability The results varied as following:1. The influence of exogenous nitric oxide donor, SNP, at concentrations of0、0.1、1.0、2.0、5.0mmol/L in Medicago sativa L.seed under25℃were studied through4days oftreatments, exogenous nitric oxide treatments could dramatically promoted germination rateof Medicago sativa L.seeds, the protective ability of concentrations of0.1mmol/L was significantly,the germination rate was91.3%.2. The influence of exogenous nitric oxide donor, SNP, at concentrations of0.1mmol/Lin Medicago sativa L.seed under4℃imbibitional chilling or not, exogenous nitric oxidetreatments could dramatically promoted germination rateand germination index, but theimpact of vigor index was different, through the determination of root activity, by using SNPunder4℃imbibitional chilling or not, the root activity and α-amylase activities wereincreased, the soluble protein were reduced.3. The Medicago sativa seeds were cultured in concentration of0.1mmol/L of sodiumnitroprusside(SNP) for12h、24h、48h under the4℃imbibitional chilling or not. the resultsindicated the activities of antioxidant enzymes were increased, such as superoxidedismutase(SOD), peroxidase(POD) and catalase(CAT), Accelerated the clearance rate ofreactive oxygen species, reduced the oxidative damage of seeds under imbibitional chillingand improved cold resistance4.Using the concentration of0.1mmol/L of SNP under the4℃imbibitional chilling, itcan improve the content of proline and soluble suger of seeds, decrease cell osmotic potential,maintain pressure balance within cells.5. Using the concentration of exogenous nitric oxide donor, SNP, at concentrations of0.1mmol/L, alleviated oxidative damage in Medicago sativa L.seed under4℃imbibitionalchilling, reduced the conductivity and MDA content, ease by increasing the content of hydrogen peroxide in reactive oxygen species metabolism, inhibited the generation ofsuperoxide anion, the effect of OH scavenging.