| Heilongjiang province ismportant commodity grain production base in ChinaDongnongdongmai1which is breeded by northeast agricultural university east is the first andthe only winter wheat which could pass the winter securely in Heilongjiang province. At present,The study of Dongnongdongmai1is focused on resistance under low temperature. however,Thefactors of snowfall and soil moisture in autumn-winter or turning green stage have greatinfluence on Dongnongdongmai1. In this assay,Wheat cultivars of Dongnongdongmai1, jimai22and longmai26Were used as experimrntal materials.They are treated with7different soil moisturesincluded85%-90%(serious floods),75%-80%(floods),65%-70%(light-flood),60%(suitablefor moisture content),50%-55%(light drought),40%-45%(drought) and30%-35%(seriousdrought) at the trefoil stage,and determined the changes of physiological and biochemicalindexes and return green ratio in tillering stage,It aimed to study the effects of cross-adaptationof low-temperature and droughts or waterlogging on cold resistance of wheat and physiologicalbasis on Dongnongdongmai1, and excavate the protein related to low temperature. It providesthe theoretical basis for the development of reasonable cultivation measures to determine thesoil and moisture of winter wheat in overwintering stage. The conclusions were as follows:(1)With the dropping of temperature and stress aggravated,the ability of imembranepermeability and electrolyte leakage rate rised in three types of wheat under different coldresistance; some osmotic adjustment and antioxidant enzyme activity had changed. Among them,The soluble sugar, proline and soluble protein were rising, and the enzyme activity of SOD andPOD enhanced in Dongnongdongmai1.however, The cold resistance of jimai22and longmai26were weaker than dongnongdongmai1, The content of soluble sugar, proline and POD activitywere increased in jimai22and the content of soluble sugar was also increased in longmai26.theother phy-biochemical indexes stop growing or declining at the later stage under lowtemperature. The electrical conductivity of dongnongdongmai1was lower than the others; Theosmotic adjustment and antioxidant enzyme activity were higher than both of others in the sametemperature and soil moisture. It showed that the physiological changes of osmotic adjustmentand antioxidant enzyme system at low temperature are physiological basis to increase the cold resistance of dongnongdongmai1.(2) It significantly increase the contents of solubie sugars, soluble protein and proline, theactivities of SOD, POD in the stem under soil surface of three wheats at low temperature. Andthe ativities of POD in middle drought and light floods was higher than the normal. At the sametime, The decline of relative conductivity high of green rate in the stem of wheat with thetreatment of light drought,and revealed that moderate drought induced cross adaptability ofwheat under low temperature stress.(3) The proteins of cross adaptation of drought and low temperature onDongnongdongmai1include acetyl coenzyme A carboxylase subunit alpha typeCarboxyltransferase, fructose kinase, triosephosphate isomerase, malate dehydrogenase, NAD(P) H-quinone oxidoreductase, L-ascorbate peroxidase, small ubiquitin and other factors.(4) Some jimai22and longmai26had turned green after experiencing short time at lowtemperature,while only dongnongdingmai1can turn green after experiencing the whole winter.with the strong cold resistance.While the prolonged drought or waterlogging and lowtemperature stress combined on wheat, The best adaptability of dongnongdongmai1was underlight drought treatment,And green rate is highest,under the soil moisture content. It shows that itwas conducive to dongnongdongmai1overwintering while the soil water content was50%to55%of soil maximum moisture capacity (52%). |
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