The Regulation Mechanism Of Water Quality On Protected Cultivation Of Delayed Grape In Different Growth Period

Experimental study were conducted on the regulation mechanism of water quality on Protected Cultivation of delayed grape in different growth period during May to December in2014 in Zhangye irrigation experiment station,we had a discussion on the effects of moderate and severe regulated deficit irrigation,and the soil moisture changes at different growth period of delayed grape,analyzed the relationship on the response mechanism of water regulation and the crop stress resistance between physiological biochemical indexes and endogenous hormones ABA in grape leaves,Studied the influence of moisture control on appearance quality as grape size and nutritional quality index such as soluble solids,sucrose,fructose,glucose the titration acid and anthocyanin,in order to find out the more efficient water quality cultivation for the delayed grape,The test results show that:（1）The soil moisture content of grape greenhouse can have different degrees of change if the the implementation of regulated deficit irrigation occurs in different growth stages.The gr apes’growth is not obviously affected with water deficit in sprout stage,but it has a more obv ious change if moderate and severe regulated deficit irrigation is in the other growth period w hich mainly displays in the soil surface layer of 0 to 40 cm,while deep soil moisture content is regulated by the deficit irrigation.0-40cm deep soil moisture in greenhouse significantly reduced,while 40-80cm deep changes gently.（2）The antioxidant activity such as SOD,POD and CAT may reflect a certain period of plant drought resistance ability.The test showed that the SOD,POD and CAT activity of grape leaves and plant drought resistance was positive correlation,the activity of SOD,POD,and CAT activity were positively correlated.Different growth stages of water deficit stress will lead to these three kinds of enzyme activity change.As can be seen from the test that SOD activity of grape leaves increased significantly after moderate water regulation,which can enhance the capacity of antioxidant system.The test shows that the content of SOD greatly increased in new shoot growth period and the expansion period on moderate water deficit treatment.For severe deficit in different growth period,SOD activity increased later and then decreased rapidly,which is because that the severe drought stress caused cell membrane damage in grape leaves,thus reducing the SOD activity,The changes of POD and CAT activity is in accord with SOD changes.（3）In the whole growth period,Regulated Deficit Irrigation on different treatment in different stages can increase MDA content.Changes of soil relative water content and MDA content showed a significant negative correlation（r=-0.961*）.After deficit treatment,with the increase of stress level,the content of MDA may increase,the ability of scavenging O^2-reduced,the degree of membrane lipid peroxidation improved,grape leaves under drought stress damage also strengthen.The leaves were maximum stress after severe deficit irrigation which was worst to plant drought resistance.（4）The ABA concentration increased sharply after regulated deficit irrigation at different growth stages.In the early growth of grape under the condition of water stress,leaf ABA concentration decreased slightly,while the concentration of ABA increased in the middle and late growth stage of grape under the condition of water stress.The accumulation of ABA increased,which can stimulate the leaf stomatal closure,reduce water consumption,alleviate the drought.In this experiment,in expanding stage-coloring and coloring stage to mature stage after water deficit,ES,CS in severe water deficit treatment can significantly increase the concentration of ABA,which is better to plant drought resistance.Mild water stress can improve IAA,ABA content in Grape Leaves,which can be seen as the plants under water stress on the hormone balance adjustment the realization of self protection.（5）Grape size is greatly affected by soil moisture.transverse and longitudinal diameter were decreased after regulated deficit irrigation at expanding period.Especially after severe deficit irrigation,longitudinal diameter of G₂₄treatment reduced to 2.157cm,which decreased6.82%compared to the control,G₂₃treatment decreased 5.83%compared to the control;fruit longitudinal diameter increased significantly.In the bud,shoot growth period,mature period,moderate water regulation can conserve water under the premise of increasing grape size.（6）Grape soluble solids content was the highest on moderate water deficit irrigation treatment(G₁₃)in blossom period,which reaching at 18.278%;When we had water regulation in the enlargement period,G_24、G₁₄treatment get the highest titratable acid content,which had a significant difference between these two treatments and the control treatment.Treatment G₂₂got the highest anthocyanin content,the content is higher than CK;EA treatment was the lowest,this showed that excessive irrigation will significantly reduce the content of anthocyanins.Water deficit had great influence on soluble solids,titrable acid and anthocyanins,these quality index can be used as the quality index of water sensitivity.（7）Water deficit irrigation at different growth stages on the change of content of fructose and glucose and sucrose are more obvious.Treatment G₂₃’s（blossom period of severe deficit）fructose content is the highest,reaching at 15.43%;The sucrose content in EA treatment was highest,compared with CK increased by 25.20%,which showed that high water treatment at the fruit enlargement period delayed the transformation of sucrose to glucose and fructose in grape berries,which can delay fruit maturity;The glucose content of treatment G₁₅was as high as 13.44%,glucose,sucrose and fructose is more sensitive on water regulation,these can be used as a sensitive index of water quality control.