Study On The Mechanism Of Auxin And Sugar Regulating The Development Of Pistil In Xanthoceras Sorbifolia Bunge

The sugar accumulation of Xanthoceras sorbifolia Bunge inflorescence is an important factor in determining its fruit setting rate.Among them,the metabolism of pistil sugar and hormones is closely related to its development.In this study,pistil of Xanthoceras sorbifolia Bunge was used as experimental material,sucrose,auxin（IAA）,auxin inhibitor 2,3,5-triiodobenzoic acid（TIBA）solution and ring peeling were used to treat pistils（apical inflorescence and lateral inflorescence）,clarified the laws of pistil growth and metabolism of sugar and hormones,then analyzed the effects of different treatments on the metabolism of pistil sugars and hormones,explored the response mechanism of inflorescence sugar accumulation to sugar and auxin signals.Research indicates:1.The apical,lateral inflorescence pistils of Xanthoceras sorbifolia Bunge are bisexual flowers from the flower bud stage to the megaspore mother cell meiosis stageⅠ,and the lateral inflorescence pistil is aborted in the late development period,mainly due to the sugar accumulation and high GA₃and IAA level.The soluble sugars in the pistil tissue of Xanthoceras sorbifolia Bunge are mainly sucrose,fructose and glucose,which accumulate as the pistil grows and develops.Hormones regulate each other with the accumulation of sugar,and work together on the development of pistil.When the pistil development of the apical inflorescence was completed,the contents of sucrose,fructose and glucose accounted for 44.06%,14.40%and 41.60%of the total sugar content of the pistil respectively.The contents of glucose,sucrose and fructose in the pistils of lateral inflorescence accounted for 55.37%,16.70%and 14.44%of the total sugar content,respectively.The abortion of the pistil in the lateral inflorescence at the later stage of development is mainly due to insufficient sucrose accumulation and high levels of GA₃and IAA content.2.The effects of sucrose and ring stripping treatment on the metabolism of sugar and hormones during the development of inflorescence pistils are shown in the later stages of development,in which the contents of total sugar,sucrose and IAA are greatly affected,and there is a significant difference from the control group.The IAA content,SS decomposition direction activity and ABA content in the apical and lateral inflorescence pistils are significantly positively correlated with the sugar content,and have the strongest response to exogenous sugar signals.They positively regulate the sugar accumulation in the inflorescence pistil and participate in the regulation of pistil development.3.The effects of auxin and auxin inhibitor treatment on the metabolism of sugar and hormone during the development of inflorescence pistil are shown in the early development period,in which the enzyme activity of SS synthesis direction,total sugar and ABA content are greatly affected,compared with the control group significant difference.The activities of sugar metabolism-related enzymes and IAA content in the apical and lateral inflorescence pistils are significantly positively correlated with the content of exogenous auxin.The two positively regulate the sugar accumulation in the inflorescence pistil and participate in the regulation of pistil development.The research results revealed the developmental rules of pistil and the metabolism of sugar and hormones in different positions of Xanthoceras sorbifolia Bunge,and clarified the effects of different treatments on the metabolism of pistil and sugars and hormones in different positions,which laid a foundation for the study of pistil development mechanism.