Effects Of Exogenous Nitric Oxide On Seed Sprouting And Seedling Physiological Characteristics Of Alfalfa Under Water Stress

Nitrous oxides (nitric oxide， NO) Distribute over a kind of gas living beings active molecule ofthe organism extensively， the active member of living beings that it is the plant the weight wants，participate in the adjustment of a lot of growth course of plant， include promoting seeds to sproutand take shape with lateral root， inhibit aging of maturity of the plant tissue， participate in thedefence of resisting diseases of the plant and coerce reacting etc.. Relevant there is less influenceresearch of drought that the alfalfa is able to bear correctly the other sources NO， this text is withthe alfalfa king (Medicago sativa L. cv. Emperor) With Germany’s treasure (Medicago sativa L.cv. Derby) It is a material， support general sodium (Sodium nitroprusside， SNP) of nitre ofbody with NO，Gather ethylene glycol (PEG-6000) Deal with seed of the alfalfa and seedling asthe infiltration modulator imitating the moisture and coercing， studying NO will coerce alfalfaseed sprouting， seedling growth， root development， only shutting ultra oxide content in thecharacteristic， blade and resisting oxidase activity to the moisture， canvass the moisture andcoerce lower NO to be able to bear the drought physiological regulating function to the alfalfaseedling. The main result of study is as follows:1. The moisture is coerced to inhibit germination tendency， long and dry material of germinationpercentage， plumule long， radicle of the seed of the alfalfa from accumulating notably， improveseeds and sprout a， in the course?-Amylase， protein hydrolase are active， accelerate starch，proteolysis and accumulation of soluble candy， soluble albumen and free amino acid; It make theseed sprout a， in the course that the other source NO is dealt with?-Amylase， protein hydrolaseactivity are further raised， the starch content is reduced， soluble albumen and soluble candycontent rise， make the content of free amino acid keep under an appropriate density， improveseed sprout tendency， germination percentage， plumule， the intersection of radicle and long dryaccumulation of material.2. Coerce a high， dry weight and reducing notably of relative water content of the increasealfalfa seedling of the intensity with the moisture， rhizome than change last difference，after risingearly than showing as in rhizome of alfalfa seedling Wang， opposite just in but Germany treasure，if you can’t coerce， last their rhizomes at moistures severe than highest. Can improve the moistureand coerce a high， dry weight and relative water content which makes the alfalfa seedling whileadding the other source NO， explain the harmful effects that the other source NO can relieve themoisture and coerce and grow to the alfalfa seedling.3moderate water stress can promote the growth of alfalfa seedlings root elongation and dry matter accumulation and enhance root activity, which promote drought resistance weaker for alfalfavarieties obvious. Water stress will inhibit lateral roots and promote MDA accumulation, and thiseffect will vary the intensity of water stress increases strengthened. Adding exogenous NO undermoderate water stress can promote root root length, lateral root number, root activity, and reducethe accumulation of MDA in severe water stress can increase the volume and surface area of themain root, in order to improve its water and on the surrounding mineral nutrition absorptionefficiency for the latter compensatory growth after rehydration provide the material basis.4peroxide content in leaves of alfalfa seedlings will be strengthened as water stress increases,drought resistance weaker than alfalfa varieties which increases the amount of drought resistantvarieties. Adding exogenous NO can significantly reduce alfalfa seedlings of ROS levels, relieveplant cells peroxidation, increased drought resistance.5. Alfalfa seedling leaves SOD, GPX and GR activities increased with water stress increased at firstand then decreased its activity in moderate water stress intensity reaches the maximum; severewater stress in drought resistance of alfalfa leaves king SOD, GPX and GR activity decreased levellower than the Depot. The CAT and APX will increase with the stress intensity continued to rise.Exogenous NO can significantly improve moderate and severe water stress in leaves of two alfalfavarieties SOD, GPX, CAT, APX and GR activity, which is consistent with the trend peroxidecontent.6. Moderate and severe water stress can significantly reduce alfalfa leaf Pn, Tr, GS and WUE, andcan increase the value of Ci, indicating strength in this stress, alfalfa Pn decrease was mainly causedby non-stomatal factors. Exogenous NO can significantly improve the Pn, Tr, GS and WUE, leavingCi decreased, indicating that exogenous NO treatment inhibits the mesophyll cells decreasedphotosynthetic activity of alfalfa, alfalfa maintain a high photosynthetic function.7. Under water stress, addition of NO can significantly improve the moderate water stress of watersensitive alfalfa seed germination rate and seedling height, dry weight, root length, lateral rootnumber, root dry weight, chlorophyll content, peroxidase activity, Pn, Tr, Gs, WUE and other thanthe control by more than the drought resistance of alfalfa. Under water stress and exogenous NO islimited on the drought resistance of Alfalfa increased under moderate water stress, the effect isbetter than the severe water stress.