Study On Waterlogging Resistance Identification Method And Its Physiological Characteristic Of Wheat

In one of the three Chinese wheat-producing area,wheat planting area accounted for about 1/4 of the total area of the Southern China winter wheat region,especially in the region of Yangtze River,due to excessive precipitation of wheat caused by waterlogging,seriously affected the regional wheat production.A lot of research have been done on waterlogging effects on wheat growth by predecessor,and they think the late jointing booting stage and flowering stage,grain filling stage is waterlogging sensitive period.This study attempts to find a simple rapid and reliable screening method for Wheat Cultivars Identification index indicative stains through measurement and test,on the growth,physiological and photosynthetic characteristics and other aspects of the formation of Waterlogging Tolerance Identification and screening method for identification of waterlogging indicators,at the same time through the growth and the fluorescence dynamic critical period in different tolerance wheat waterlogging,analysis the waterlogging mechanism,for the identification of waterlogging tolerance and provide a theoretical basis for the breeding of wheat with waterlogging tolerance.155 wheat varieties are conducted with a artificial simulation waterlogging test in germination and seedling stage,and the germination rate,fresh weight of single plant,root fresh weight per plant and other indicators are measured.Combining germination rate decreasing amplitude with waterlogging index,different anti-waterlogging ability in germination and seedling stage is compared.32 varieties whose generation rate decreasing amplitude is zero are conducted with a correlation analysis of waterlogging in germination and seedling stage breeds and heading flowering period,and the result is there is a significant correlation between bud weight and maximum root length and the yield.During the wheat's heading flowering period,12 days of waterlogging has a non-significant influence on SPAD of base leaf,but its influence on SPAD value of 2nd leaf to 4th leaf reaches a very significant level;In the control area of normal moistUre.A short-term waterlogging during the heading flowering period makes the content of chlorophyll a and chlorophyll b of flag leaf reduce,but has no significant influence on carotenoids.Meanwhile,it conducts a clustering analysis on waterflooding treatment yield and waterlogging index of 50-scores advanced lines variety,and it is divided into five categories.In order to study the effect of waterlogging on wheat's physiology and growth in flowering period,the test takes 15 wheat varieties selected from the clustering analysis in 2015 as the materials,and conducts an artificial simulation waterlogging treatment in heading flowering period.The results show that,after a short-term waterlogging treatment(7 days)in heading flowering period,wheat's MDA value of top three leaves,SPAD value of top leaf,2nd leaf and 3rd leaf,and oven-dry weight of leaves have no obvious changes.During the period of 7 days to 14 days after the waterlogging treatment,SPAD value of top leaf fells slightly.During the period of 14 days to 28 days after the waterlogging treatment,SPAD value of top leaf drops significantly.7 days.after the waterlogging treatment,SPAD value of 2nd leaf and 3rd leaf begins to drop significantly.After a shorter-term(7 days t0 14 days)waterlogging,SPAD value of 2nd leaf and 3rd leaf significantly drops.When measuring SPAD value,choosing 2nd leaf or 3rd leaf can reflect the damage efifect of waterlogging on photosynthetic pigment.21 days to 28 days after the waterlogging,dry matter accumulation begins to have more significantly reduce.During the period of 14 days to 28 days after the waterlogging treatment,MDA value of wheat's top three leaves in waterlogged area rises most significantly.Under the circumstance of a longer-term waterlogging,wheat's damage degree can be judged according to MDA content;If the waterlogging period is shorter(less than 14 days),MDA content of wheat leaf can't reflect its damage degree.Taking 8 winter wheat combinations as the test materials,it conducts an artificial simulated waterlogging treatment in filling stage and heading and flowering period,and studies the fluorescence kinetics parameters and photosynthetic characteristics of flag leaf.The results show that,7 days after the waterlogging treatment,PS II electron transfer activity of flag leaf reduces,and the excess light energy dissipate into the heat energy,but the biggest photochemical efficiency decrease is not significant.10 days after the waterlogging treatment,PS ? electron transfer activity of flag leaf rises again,and the heat energy dissipated from the excess light energy reduces,but the biggest photochemical efficiency significantly reduces.10 days after the filling period finishes,the flag leaf's net photosynthetic rate,stomatal conductance and intercellular CO2 concentration have a larger decline trend,and its premature aging is obvious.There is a significant positive correlation between Fv/Fm and flag leaf's photosynthetic rate;there is a significant positive correlation between Fv/Fm and stomatal conductance and intercellular C02 concentration.