Effect of Soil Drying-Wetting Alternation on Dry Biomass Accumulation and Reallocation at Maize Flowering Stage

This is popular by potted experiment in the drought injury test,but it cannot get the full response on drought stress and on compensation growth at maize flowering stage.To set controllable test of pool planting and canopy of drought studied on dry biomass accumulation and reallocation of maize under soil drying-wetting alternation of different soil layer and drought degree and genotype.The result showed that severe drought stress at flowering stage urged fast senescence of leaves and stable growth of root system and then maintaining growth of stem,these bring to increase the rate on stored originally substance of leaves and root system transporting to spike and to decline the rate on stored originally substance of stem transporting to spike after flowering,it was 8.48 and 14.68 percents more than the light drought.After re-watering,it was to compensate loss of drought at earlier stage that increase the rate of photosynthetic yield transporting to spike and the rate of contribution to dry biomass because of short-time slowing down on senescence of source organs,it was 6.21 percents more than the light drought.Because dry weight per plant of severe drought stress had reduced by 36.8 percents to light drought at maturity stage,compensation growth after flowering could not enough to compensate,so dry biomass accumulating decreased in severe drought stress.It was obvious that root system and stem and sheath maintain relative stabilization under water deficit on different drought degree that was a foundation of compensation growth of plant after re-watering;these reveal the compensation effect after flowering under soil drying-wetting alternation.And then studies discovered that rate of dry biomass accumulation(RDBC) on varieties after re-watering was C14C19C202,but RDBC in drought stress was C202C19C14.Therefore,the characters of compensation growth and drought resistance on genotype had difference types of representation;the variety on drought resistance and saving water at seasonal drought area had been definite drought resistance in drought stress and the bigger effect of compensation growth after re-watering.The study adopted the varieties which were the type on drought resistance and higher compensation growth(Chengdan 19),and the type on water sensitivity and the highest compensation growth(Chengdan 14),and the type on drought resistance and lower compensation growth(Chengdan 202).To add soil layer and to lighten drought degree were beneficial to enhance the ability of compensation growth.Therefore to add soil layer not only to strengthen the crop capacity of drought resistance significantly,but also to take the advantage of the potential on compensation growth.The degree of compensation growth concerns the early drought.That should do more research on the value point of soil water capacity on profitable compensation growth under soil alternate drying-wetting of different growth stage and soil layer of different crops or varieties.