Responses to Drought of Relationships between Dry Matter Partitioning and Development Process of Maize
In order to deeply understand the variation characteristics of dry matter partitioning(DMP)of above ground organs of maize with development stage(DVS)and their response mechanisms to drought and to improve DMP parameterization scheme,based on the 4-year water stress experiments conducted in vegetative and reproductive growth stages of maize'Danyu405'and'Xianyu335'in Jinzhou,the above-mentioned characteristics and their responses to drought were investigated.Results showed that under the normal water supply condition,the maize ear dry matter weight(DMW)had an increasing trend with DVS which is similar with that of the total above-ground DMW,and the leaves and stalk DMWs both saw the change trend of increase and then decrease with DVS.The DMP rate(DMPR)of maize leaves decreased linearly or exponentially with DVS,and DMPR of stalk increased from emergency to florescence and silking period and then decreased gradually until maturity.However,the ear DMPR increased linearly with DVS.The dry matter partitioning rate of increment(IDMPR)of leaves decreased with DVS,and the dry matter redistribution(DMRD)for leaves occurred at about milk stage.Meanwhile,the IDMPRs of stalk and ear increased and then decreased with DVS,and the DMRD of stalk was slightly later than that of leaves.In the case of soil drought,the DMWs of the corn organ decreased with the enhancement of drought,and the DMPRs of the corn organ responded more belatedly and weakly to drought relative to the DMWs.In addition,the DMPRs of leaves and stalk of maize'Danyu405'increased with the enhancement and the delay of occurrence time of drought in late growth period,which is opposite to the situation of the ear DMPR,while the responses of the DMPRs of aboveground organs for maize'Xianyu335'to drought were weaker than those for maize'Danyu405'.Moreover,drought in different growth stages caused the IDMPRs of leaves,stalks,and ears to be smaller,larger,and larger than the normal values,respectively,and the DMRD of leaves to be ahead of time.In addition,weather conditions combined with abnormally high temperatures and drought led to a stagnation of ear growth,which severely inhibited DMRDs and resulted in the increase in DMPRs and DMWs of leaves and stalks relative to normal values.According to the results of the 4-year experiment,the changes in dry matter accumulation and DMP with DVS and their responses to drought showed clear interspecific differences,and were closely related to severity and occurrence time of drought.
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