Study On The Water Relationship Between Tree And Berry In The Later Growth Stage Of Delayed Cultivation Of Red Globe Grape

The delayed cultivation of Red Globe grape?DCG?is suitable for developing in Hexi Corridor,mainly due to the abundant light resources,and the picking period is 1-2 months later than other areas.The market time could be staggered with that of most deciduous fruit trees,and the economic benefit is high.After 20 years of development,the area of DCG in Hexi Corridor of Gansu Province has gradually became the most characteristic agricultural industry in Northwest China.During and after grape ripening,tomaintain the fruit quality is an important content.Low temperature and high humidity can help to maintain the berry quality,but they can cause early senescence of trees and serious diseases,and the advantage of DCG cannot be reflected.The temperature and water management in the facility should not only satisfy the tree growth,but also maintain the water relationship between tree and fruit for a long time,and it cannot reduce the quality of fruit.How to coordinate the relationship between the two has become a common concern of growers and scientific researchers.On the basis of traditional light and temperature management,this paper studied the water relationship between fruit and tree by regulating soil moisture.The results could provide scientific basis for soil water management and berry quality maintenance of DCG.The main results are as follows:1.The water consumption in the process of trees senescence decreased continuously and the main factor to determine the tree‘s water consumption was the low temperature at night.From the beginning of October to the middle of November,suitable soil water(soil volumetric water content was 0.18 m³ m^-3 and 0.21 m³ m^-3,respectively)could increase the water consumption of trees,but it could not change the trend of water consumption decrease continuously.In terms of temperature management,the control of low temperature in facilities should be strengthened in advance in early September,the night low temperature should be kept above 12°C,and the night low temperature should be kept above 8°C during the maturity period from October to mid-November.After mid-November,with the further senescence of the tree,the water consumption decreased rapidly and irreversibly to 200 g d^-1,at this stage the night temperature should be kept above 3°C.2.The good soil moisture environment could reduce the senescence of grape tree,but it can not change the trend of tree senescence and fruit ripening.The results showed that the overall water transport resistance of grape trees increased during and after veraison,and the area of water transport channels of fruiting branches,petioles and spikelets corresponding to fruit ears decreased.The photosynthetic capacity of leaves decreases and their adaptability to high temperature at noon decreases with the aging of leaves,the rapid cooling treatment caused more damage to the leaves under high water supply.In addition,the results of ABA,GH and accumulation of starch and sugar in fruiting branches confirmed that high water treatment could reduce the senescence of trees,mainly from mid-October to mid-November.3.During the period from veraison to harvest,the water relationship between tree and fruit gradually disappeared.On October 10,the net change of water content in fruits of different treatments was positive,and the water inflow and loss of fruits remained basically balanced.By October 25,the water inflow into fruits of low soil water supply treatment could not meet the berry water loss requirement,and the net loss of water in fruits was manifested as a net loss of water.On the whole,there was a small amount of water transport in xylem during the grape veraison.4.The ripening of grapes was accompanied by fruit softening and soluble solids increasing.After ripening,the fruit weight loss accelerated with the continuous loss of water.During the same period,with the increase of water supply,the turgor and firmness of grape fruit increased,and after October 25,the fruit firmness of high water supply treatment(0.24m³ m^-3)was higher.After October 25,the soluble solids in the fruits of different treatments exceeded 15%,which reached the minimum harvesting standard,and then entered the quality maintenance stage after grape ripening,but the increase rate of soluble solids in the fruits of different treatments decreased significantly.On November 25,the soluble solids of berry with high water supply(0.21 m³ m^-3 to 0.24 m³ m^-3)were only 16.8%and 15.8%,and the ratio of sugar to acid was 22.11 and 20.26,respectively.Under 0.18 m³ m^-3 soil water supply treatment,the soluble solids of fruits reached 18.7%,the sugar-acid ratio was 29.22,which was in the best quality period.5.The transcriptome datas showed that in the early stage of grape veraison?the soluble solids increased from 7%to 9%?,the differentially expressed genes of M vs L participated in five metabolic pathways involving cell wall,but did not reach signifi cant enrichment status.As the color darkens?soluble solids increased from 7%to 11%?,the differentially expressed genes of H vs L were significantly enriched in three pathways related to cell wall metabolism,and were mainly affected by COBRA-liKe protein-related up-regulated genes?GSVIVG01008128001?and pectinesterase-related do wn-regulated genes?GSVIVG01031164001?.Comprehensive analysis showed that soil water had a great influence on tree‘s water consumption,senescence and fruit quality of Red Globe Grape in the late growth stage.The volume loss of fruit under different treatments was more than 5%by late November,so the latest harvest time should be in mid-November.In order to delay the harvesting period of Red Globe grape,the construction level of greenhouse needs to be improved and the control of light,temperature and water should be improved for DCG.