阳光玫瑰葡萄生长期花芽分化形态进程及相关生理分子水平变化研究

A study on the morphological process and physiological and molecular changes of flower bud differentiation in Shine Muscat grape during fruit growing season

【目的】探讨阳光玫瑰葡萄生长期花芽分化进程及相关生理分子水平变化,为葡萄生产调控及花芽分化深入研究提供理论参考。【方法】以4年生阳光玫瑰葡萄为试材,通过徒手剥离冬芽鳞片在体式解剖镜下观察冬芽形态结构变化,测定花芽分化过程中第5节位叶片内碳水化合物、矿质元素含量及冬芽内9个成花关键基因的表达。【结果】南宁地区阳光玫瑰葡萄在新梢6片展叶期时开始花芽形态分化,在末花期进入花序原基分化期。叶片可溶性总糖、淀粉含量在花序原基分化期后显著升高。叶片P、K、Ca和Mg元素含量在花芽形态分化起始时下降,在花序原基分化后60 d时含量显著降低。冬芽中VvFT和VvSOC1基因在花芽分化起始时表达水平较高;VvLFY、VvAP1、VvFUL、VvAP2、VvAP3和VvAG基因均在花序原基分化期及花序原基分化期后80~100 d出现表达波峰,VvFLC基因在花序原基分化后60~100 d的表达水平较高。【结论】南宁地区阳光玫瑰葡萄花芽分化进程开始较早。生产上在果实膨大期和软化期前后应适当补充磷、钾、钙、镁肥,以促进果实发育、花序原基及其各级穗轴分化。VvFT和VvSOC1基因参与诱导始原基及花序原基分化,VvLFY、VvAP1、VvFUL、VvAP2、VvAP3和VvAG基因可能均参与促进花序原基及其各级穗轴分化。

【Objective】In order to provide a theoretical reference for the regulation and the further study of the flower bud differentiation mechanism of grape,the flower bud differentiation process of Shine Muscat grape and the physiological changes and relative gene expression in fruit growth stage were studied.【Methods】4-year-old Shine Muscat grape trees were used as the materials.During the growing season,twenty winter buds at the fifth node of the new shoots were randomly collected every three days from the five leaves separating stage with three repeats.The dissection of the lamella of winter buds was performed by hand under stereomicroscope to observe the morphological changes of the flower bud differentiation process.The differentiation stages of each bud were counted and recorded.The flower bud differentiation of Shine Muscat was divided into six stages,namely leaf bud stage,flat top stage,dichotomy stage,anlagen differentiation stage,inflorescence primordium differentiation stage and inflorescence branching axis differentiation stage.Each differentiation stage was determined according to the flower bud differentiation stage of over 75%of the sampled winter buds.After the inflorescence primordium differentiation stage,the samplings were carried out every 20 days until the fruit harvest.Phenological periods were recorded for each flower bud differentiation stages and sampling days after the inflorescence primordium differentiation stage.Meanwhile,twenty winter buds were collected to determine the expression of nine key flowering genes VvFT,VvSOC1,VvLFY,VvAP1,VvFUL,VvAP2,VvAP3,VvAG and VvFLC,five leaves at the fifth node of the branch were sampled for the determination of total soluble sugar,starch,mineral elements N,P,K,Ca and Mg contents with three repeats.【Results】The results showed that the flower bud differentiation of Shine Muscat winter buds started at the sixth leaf separating stage,and entered the anlagen differentiation stage at the full-blooming stage,then entered inflorescence primordium differentiation stage at the end of flowering stage.The content of N in the leaves maintained at 2.5-3.0 g·kg-1from the leaf bud stage to the inflorescence primordium differentiation stage,and then reached the lowest value at the stage of 20 days after inflorescence primordium differentiation.The changes of P,K,Ca and Mg content in the leaves were the same,these elements decreased at the beginning of morphological differentiation,and then increased twice.The first peak was found at the inflorescence primordium differentiation stage for P and Mg and at the stage of40 days after inflorescence primordium differentiation for K,and the second peak was found at the stage of 100 days after inflorescence primordium differentiation for P,K and Mg.The content of Ca in the leaves showed an overall upward trend,with a low content at the leaf bud stage and flat top stage,a significant rise at dichotomy stage,and two peaks appeared at the stage of 40 and 100 days after the inflorescence primordium differentiation.Overall,the contents of P,K,Ca and Mg in the leaves decreased significantly at the stage of 60 days after the inflorescence primordium differentiation.The flower induction genes VvFT and VvSOC1 were highly expressed during the flower buds differentiation induction stage.The expression of the VvFT reached the first peak at the flat top stage and the second peak at the stage of 20 days after the inflorescence primordium differentiation.The expression of the VvSOC1 was significantly up-regulated at the flat-top stage and reached the peak at the dichotomy stage,but kept a low level after the stage of 40 days after the inflorescence primordium differentiation.The expression of the VvLFY,VvAP1 and VvFUL were all at a low level during the early stages of flower bud differentiation.The expression of the VvLFY reached a peak at the stage of 80 days after the inflorescence primordium differentiation.The expression of the VvAP1 increased from the stage of inflorescence primordium differentiation,and reached the highest level at the stage of 20 and 100 days after the inflorescence primordium differentiation.The expression level of the VvFUL increased at the stage of the inflorescence primordium differentiation,and reached the highest level at the stage of 80 days after the inflorescence primordium differentiation.The expression of the VvAP2 reached the highest level at the inflorescence primordium differentiation stage,and showed a significant upward trend from the stage of 40 to100 days after the inflorescence primordium differentiation.During the flower bud differentiation,the expression trends of the VvAP3 and VvAG were consistent,the expressions of the VvAP3 and VvAG were down-regulated at the beginning of the flower bud differentiation,and reached highest level at the stage of 80 days after the inflorescence primordium differentiation.The expression level of the VvFLC was significantly lower from the inflorescence primordium differentiation stage to the stage of 40 days after the inflorescence primordium differentiation,but exhibited a relatively high level during the stages of 60 to 100 days after the inflorescence primordium differentiation.【Conclusion】The flower bud differentiation process of Shine Muscat grape was earlier in Nanning.More organic nutrition and main mineral elements were demanded during the inflorescence branching axis differentiation stage.In production,during the stage of before and after the enlargement and softening of Shine Muscat grapes,appropriate supplements of phosphorus,potassium,calcium and magnesium fertilizers are important to promote fruit development and normal differentiation of inflorescence branching axis.The VvFT and VvSOC1 were involved in the induction of primordium and inflorescence primordium differentiation.The VvLFY,VvAP1,VvFUL,VvAP2,VvAP3 and VvAG may be involved in the inflorescence primordium differentiation and further differentiation of development of branching axis.The high expression of the VvFLC may inhibit the expression of flower induction genes,during inflorescence branching axis differentiation stage.