| The grape(Vitis Vinifera L.)is a perennial deciduous woody vine fruit tree belonging to the genus Vitis,which is known as the world's four major fruits together with apples,citrus and bananas.According to FAO statistics,China's table grape production in 2016 was 10.2 million tons,accounting for 46.4% of the world's total grape production that year,making it the world's largest grape producer.In recent years,the planting area of grapes has gradually increased in southwestern provinces such as Sichuan,Chongqing and Guizhou,but these areas are typical areas of high temperature,high humidity,and low solar radiation.The problems of incomplete and irregular germination,vigorous nutrition growth and low yieldcaused by insufficient accumulation of cold demand for breaking dormancy have become the bottleneck of grape industry development in these areas.Therefore,in this study,grape under the conditions of rain shelter cultivation in high temperature,humidity and low solar radiationareas in Sichuan Province was used as the material.By studying the effects of different dormancy breaking treatments on the biological characteristics and the dynamic changes of total chlorophyll content of grape,the technical system of grape winter bud breaking dormancy was developed and improved.The microstructures and transcriptomes of winter buds of 'Summer Black' grape treated with cyanamide were also studied,and the regulatorymechanism of the germination of winter buds was explored.The above studies provide practical and theoretical guidance for grape winter buddormancy breaking in high temperature,humidity and low solar radiation areas in Sichuan.The following results are obtained through this test study:1.Winter bud dormancy of grape cultivated in high temperature,humidity and low solar radiation areas of Sichuan Province experienced three stages of similar dormancy,internal dormancy and ecological dormancy.Around mid-October,it is the similar dormancy stage,and from mid-October to late-December,it is the internal dormancy stage.In early January,it enteres the ecological dormancy stage.2.The experiment was carried out by orthogonal design,taking coating agent,coating time and carved bud as factors.The results showed that different treatments had effects on the phenological period of 'Xiang Yue' grape,the germination time of winter bud of 'Xiang Yue' grape was 6~28 days earlier,and the ripening time of the fruit was 6~36 days earlier.The germination time of winter bud of 'Summer Black' grape was 4~29 days earlier,and the ripening time of the fruit was 6~36 days earlier.The time advanced in germination stage and the fruit maturation stage respectively were used as the indexes to evaluate the effect of dormancy breakingof the two grape varieties.The effects of the concentration of coating agent,the time of coating and whether or not to carve the buds in this experiment were analyzed.The results of the range analysis showed that: That is,the time of bud coating is the most important to break the dormancy of grape winter bud.The phenological observation of 'Summer Black' and 'Xiang Yue' grape,germination rate,branch formation and fruit branch rate of winter bud,and fruit quality of grape treated with different breaking treatments were analyzed.The results showed that the good effect was to break the dormancy of 'Xiang Yue' and Summer Black' grape in high temperature,humidity and low solar radiationareas in Sichuan Province around mid January,with 2.5%-3.0% cyanamide coating combined with bud carving treatment.The germination rate of 'Xiang Yue' grape was significantly higher than that of the control.The germination rate,the branch formation rate and the fruit branch rate of Summer Black' grape was significantly higher than that of the control.There were no significant difference between the fruit quality and the control of 'Xiang Yue' and 'Summer Black' grape,all of them are the inherent quality of the variety.3.On the basis of previous studies,the changes of microstructure and ultrastructure of winter bud meristem of 'Summer Black' grape with 2.5% cyanamide treatment were also observed.The results showed that the microstructure and ultrastructure of the meristem showed obvious changes when treated with cyanamide for 15 days,but the change was not visible to the naked eye.The microstructural growing point of the meristem of winter bud of grape gradually increased and elongated,the top gradually widened,the number of cells increased,and the growing point gradually protruded upward,widening and flattening.The differentiation of leaf primordium increased,the main axis of bud is differentiated and elongated,and the internodes became wider.With the growth of the growing point,new leaf primordium was constantly growing.The ultrastructural study also found that when treated with 2.5% cyanamide of 'Summer Black' grape for 15 days,the volume of the cell nucleusincreased,the number of organelles,especially mitochondria,Golgi apparatus and vacuoles increased,the volume of vacuoles changed from large to small,and the plasmodesmatathickened and increased.4.Taking the singlebud branch cut from the branches of 'Summer Black' grape after falling leaves of the year as the experimental materials,the dormant buds of treated for CK,treated with clear water for 15 days and treated with 2.5 % cyanamide for15 days were sequenced by transcriptome.A total of 29551 genes were detected in the sequencing results,accounting for 73.29% of the designated reference genomes.Among them,660 new genes were detected and 545 genes were functional annotated through sequence alignment and amino acid sequence prediction with each database.Compared treated with clear water for 15 days and treated with 2.5 % cyanamide for15 days,1774 DEGs were detected,1090 of which were up-regulated and 684 down-regulated.KEGG analysis showed these DEGs were mainly located in pathways such as photosynthesis,starch and sucrose metabolism,fatty acid metabolism,phytohormone signal transduction and phenylpropanoid biosynthesis.GO functional annotation showed these DEGs are mainly involved in cellular processes,metabolic processes,nitrogen compound metabolism,emergency response and biological regulation. |
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