拉枝处理对‘翠冠’梨成花的影响及其调控机制

Effect and Regulation Mechanism of Branch-drooping on Flower Bud Formation of Cuiguan Pear

以‘翠冠’梨为研究材料,对枝条进行90°拉枝处理,探明拉枝对梨成花及其相关基因(LFY、TFL1和FT)的表达以及内源激素和营养物质含量的影响。结果表明:(1)90°拉枝处理能够大幅度提高‘翠冠’梨的成花率。(2)与不拉枝处理相比,90°拉枝处理的花芽分化促进类激素——玉米素(ZT)和脱落酸(ABA)的含量上升,花芽分化抑制类激素——赤霉素(GA3)和生长素(IAA)的含量下降,可溶性糖含量和淀粉含量在花芽分化期间大量积累,全氮含量(N)下降,C/N比显著提高,且成花促进基因(LFY和FT)的表达量上升,成花抑制基因(TFL1)的表达量下降。(3)相关分析显示,LFY、FT基因表达量与ZT、ABA含量呈显著正相关关系,与GA3、IAA含量呈显著负相关关系,与可溶性糖含量、淀粉含量和C/N比呈显著正相关关系,与全氮含量呈显著负相关关系,而TFL1基因表达量与LFY、FT基因表达量呈显著负相关关系。研究认为,拉枝处理通过提高成花过程中花芽分化促进类内源激素含量和营养物质含量,上调成花促进基因表达水平,以及这些指标间相互影响共同调控提高‘翠冠’梨成花率。

The cultivar of ＇Cuiguan＇ was selected as material to study the effects of branch-drooping on the flower bud formation,the expression of blossoming related genes LFT, TFL1 and FT,and the content of endogenous hormones and nutrients. Results showed that ： （1） 90° branch-drooping treatment significantly increased the flower bud formation rate of ＇Cuiguan＇ pear by a large margin. （2）After the treatment of branch-dropping, the expression of flowering promoting genes LFT and FT increased, while the expression of flowering suppressor gene TFL1 decreased. The contents of flower bud differentiation promoting hor- mones ZT and ABA increased, while the contents of inhibiting hormones GA3 and IAA decreased. The ratio of C/N improved observably,while the content of nitrogen（N） descended. At the same time,the contents of soluble sugar and starch showed a large accumulation during flower bud differentiation. （3）Correlation a- nalysis showed that LFY and FT gene expression had a positive correlation with the contents of ZT and ABA,soluble sugar, starch, and the ratio of C/N. And it had a negative correlation with the contents of GAa ,IAA,N,and TFL1 gene expression. This study suggested that branch-drooping treatment increased flowering promoting gene expression level by increasing flower bud differentiation promoting class endogenous hormone contents and nutrient contents during the process of flower bud formation, as well as interactions between these indicators together to improve ＇Cuiguan＇ pear flower rate.