| In this experiment,the 4-year-old Shine Muscat grape was used as the test material.The morphological changes of the flower bud differentiation process of winter buds were observed by freehand section;the expression of nine flowering genes such as Vv FT,Vv SOC1,Vv LFY,Vv AP1,Vv AP2,Vv AP3,Vv AG,Vv FUL and Vv FLC were analyzed,and the physiological and molecular laws of flower bud differentiation of winter buds were analyzed;the expression of nine flowering genes in buds was measured during the next winter bud germination process,and the bud germination was analyzed the molecular change law in the process;comparing the difference in expression of the above 9flowering genes in the winter buds of the three treatments of the two-harvest-a-year cultivation with second-season fruit,the two-harvest-a-yearcultivation without second-season fruit and the one-harvest-a-year cultivation during the second fruits development of the two-harvest-a-year cultivation;investigating the effect of second-season fruit development on the next year’s flowering of winter buds.the result shows:1.Exploring the law of flower bud differentiation of winter bud of Shine Muscat grape:(1)The expression of 9 flowering genes in spatiotemporal expression is basically consistent with the results reported by other predecessors in other varieties.Vv SOC1 and Vv FT are related to the initiation of flower bud differentiation,and are involved in the formation of inflorescence meristems with Vv LFY,Vv AP1,Vv AP2 and Vv FUL.The difference is that the expression level of Vv LFY at the initial stage of flower bud differentiation in Shine Muscat grape is low;the expression level of Vv AP3 and Vv AG at the initial stage of flower bud differentiation is significantly reduced;the expression level of Vv FLC around formation of main cob of inflorescence period is significantly lower than other periods.(2)The content of total N,P,K in the leaves fluctuated slightly in the early stage of flower bud differentiation,and significantly increased in the late stage of flower bud differentiation.The contents of Ca,total soluble sugar and starch showed a significant upward trend during the process of flower bud differentiation.All above results are basically consistent with the results reportedby other predecessors in other grape varieties.The difference is that the Mg content fluctuates greatly during the flower bud differentiation process,and the content is higher during the main cob of inflorescence and the late flower bud differentiation period.(3)The expressions of up-regulated genes Vv AP2,Vv AP3,Vv AG and Vv FUL were positively correlated with the expression of Vv LFY;the contents of starch,total soluble sugar,P and Mg were positively correlated with Ca content;starch,total soluble sugar and Ca content,there was a positive correlation with the expression of Vv AP1;there was a positive correlation between the total soluble sugar content and the expression of Vv LFY;and there was a significant negative correlation between the change of Vv SOC1 and the total soluble sugar.2.In the process of winter bud germination,in addition to the floral organ characteristic genes Vv AP1,Vv AP2,Vv AP3,Vv AG and Vv FUL,flowering integrons Vv FT and Vv SOC1 are also involved in the development of flower organs.In addition to Vv FT and Vv AG,the expression of other seven genes in the early stage of bud germination changes significantly,indicating that winter bud germination is are regulated by multiple flowering genes together.3.Effects of the two-harvest-a-year cultivation during the second fruits development of Shine Muscat grape on winter bud differentiation and flower formation:(1)In the two-harvest-a-year cultivation treatment,there was a deathphenomenon of winter buds during fruit-setting period.The flower bud rate was lower than the treatments of one-harvest-a-year cultivation and the two-harvest-a-year cultivation without second-season fruit during the fruit-setting period and the maturity period.The germination rate and flowering rate of the next year winter bud of two-harvest-a year cultivation treatment was lower than one-harvest-a-year cultivation.It showed that the development of two-season fruit in two-harvest-a-year cultivation reduced the germination ability of winter buds and the ability to differentiate into inflorescences.(2)By analyzing the expression laws of 9 flowering genes during the development of two-harvest-a-year cultivation during the second-season fruit,it was found that the relative expression of flowering inhibitor Vv FLC in the winter buds of the two-harvest-a-year cultivation during fruit-setting were significantly higher than the treatments of one-harvest-a-year cultivation and pruning without leaving fruits;The expression level of the up-regulated gene Vv AP1 was significantly lower than that of other two treatments;The relative expression of the flowering integron Vv FT in the winter buds of the the two-harvest-a-year cultivation during the second season fruit softening period was significantly lower than other two treatments.It indicated that the development of the two-harvest-a-year cultivated second-season fruit caused the above-mentioned genes expression difference during the stagnation period of flower bud differentiation,which may be related to the decrease in the flowerbud rate of winter buds. |
