Effects of Spraying Exogenous ABA or GA on the Endogenous Hormones Concentration and Filling of Wheat Grains

【Objective】 The objective of the experiment is to explore the relationship between exogenous ABA and GA to the levels of endogenous hormones in grains and the grain filling,and provide a theoretical basis for increasing grain weight under the regulation of exogenous hormone.【Method】The field experiments were carried out at Taian Experimental Station of Shandong Agricultural University,two cultivars Shannong 1391 and Gaocheng 8901 were planted in the farm,exogenous ABA or GA to the spikes were sprayed at initial grain filling stage,spikes were sampled after anthesis till maturity,and grains were partitioned into two groups,superior grains(the 1st and 2nd grains from the basal part of middle-spikelets) and inferior grains(the 3rd and 4th grains from the basal part of middle spikelets or the 3rd grains or the 3rd,4th and 5th grains).Then,taking the grains for the analysis of endogenous hormone levels and grain filling characteristics.【Result】Spraying exogenous ABA or GA enhanced the grain weight.Spraying exogenous ABA enhanced the weight of superior grains.Spraying exogenous GA enhanced the weight of superior and inferior grain.At the same time,spraying exogenous GA enhanced the levels of endogenous GA in grains.Spraying exogenous ABA enhanced the levels of endogenous ABA in grains.Spraying exogenous ABA or GA enhanced the IAA and CTK content at middle and later periods of grains filling.Grain filling characteristics suggest that spraying exogenous ABA or GA extended the grain filling stage.Spraying exogenous ABA enhanced the initial grain filling rate of superior grains.Spraying exogenous GA enhanced the grain filling rate at middle and later periods of grains filling.【Conclusion】 Spraying exogenous ABA or GA regulated the levels of endogenous hormones in grains,aslo the initial grain filling stage and duration of grains filling stage,and then,grain weight was regulated.Spraying exogenous ABA enhanced the grain weight by enhancing the weight of superior grain.Spraying exogenous GA enhanced the grain weight by enhancing the weight of superior and inferior grain.