Analysis Of The Effect Of Anti-trianspirant On Wine Grape And Wine Quality In Hot Climate

This study is aimed at the problem of high maturity and low acidity caused by high summer temperature in the hot grape producing area,which affects the quality of wine.From2017 to 2018,in the Xinjiang region with typical hot climate conditions,the“Vitis vinifera L.cv.CS（CS）”and“Vies Vinifera L.cv.Riesling”were test materials for anti-transpirant spraying test,to explored the comprehensive effects of anti-transpiration on photosynthetic characteristics,physiological indexes,fruit and wine-related quality in hot climate,aimed to provide a theoretical basis for improving the comprehensive quality of wine grapes and wines in hot climate producing areas.The main findings are as follows:（1）Study on photosynthetic characteristics:Compared with water spray control,anti-transpiration significantly reduced the net photosynthetic rate and stomatal conductance of both CS and Riesling.However,the intercellular CO₂ concentration and transpiration rate were inconsistent in them;it had no significant effect on water use efficiency of the two varieties.（2）Studies of stomatal characteristics and physicochemical:（1）Anti-transpiration significantly reduced the stomata width（41.02%,46.94%）,degree of opening（59.59%,67.43%）and distribution density（13.84%,4.97%）of CS and Riesling,respectively.Significantly reduced Riesling pore length 5.14μm（25.20%）to reducing the large amount of water loss in hot climates.（2）Significantly reduced the content of malondialdehyde（MDA）,free proline in two varieties and soluble protein of Riesling,it had no significant effect on chlorophyll content.（3）Grape size,maturity and phenolic substances:（1）Anti-transpiration has no significant effect on the size of CS,in 2017 and 2018,significantly increased the single spike weight of Riesling by 22.0 g and 4.8 g,respectively.（2）Significantly delay the accumulation of reducing sugar and the degradation rate of organic acids.For CS,in 2017 and 2018,the reducing sugars were significantly reduced by 6.6 g/L and 16.6 g/L,respectively,and the total acid was increased by 0.57 g/L and 0.98 g/L.For Riesling,the reducing sugar was significantly reduced by 11.7 g/L and 14.5 g/L for two years,increased total acid 0.76 g/L and 1.46 g/L;glucose and fructose content were significantly reduced.（3）In 2017 and 2018,it significantly reduced the total anthocyanins,total flavonoids,total Flavan-3-ol of CS;Significantly increased the total phenolic of Riesling 6.19 mg/g,1.8 mg/g,Total flavonoids2.95 mg/g,3.88 mg/g.（4）Significantly reduce the total amount of anthocyanin monomer and each component in the skin of CS;in 2017,significantly reduced the total amount monomer phenol of CS and Riesling by 31.26%and 22.61%,on the contrary,in 2018,significantly increased the total amount of monomeric phenols by 65.55%and 10.15%.However,the flavanol monomeric phenol content of CS was significantly increased in 2 years by 22.91%and 403%,respectively.（4）Research on physicochemical and phenolic of wine:（1）Anti-transpiration have a significant effect on reducing the alcohol content of wine.In 2017 and 2018,alcohol of CS wine was reduced by 0.71°and 1.36°,respectively.The Riesling alcohol was reduced by0.39°and 0.52°respectively.（2）Significantly increase the total tannin content of CS wine（5.24%,0.94%）,but reduce the anthocyanin content in 2 years（2017 is not Significant）.（3）Significantly reduce the total amount of anthocyanin monomer and each component of CS.;Both significantly increased the flavanols monomeric phenol by 16.59%and 5.78%in 2years,respectively,and reduced phenolic acids and flavonols.For Riesling,it had no significant effect on the total amount of monomeric phenols and each component in 2017,but significantly reduced in 2018.（5）Study on grape and wine aroma:（1）For fruits:In 2017 and 2018,obviously reduced aldehydes（64.23%,12.01%）and"other types"aroma substances（52.06%,29.75%）in CS,which could increase the content of esters（195%,77.08%）;for Riesling,significantly reduced total aroma（7.91%,1.67%）,esters（0.80%,17.37%）,acids（42.04%,42.08%）.（2）For wine:Significantly increase the aroma of CS alcohol（58.41%,8.76%）and“others”（530%,196%）;for Riesling,significant increases ketones（76.23μg/L,312%）and reduces the content of“other types”（30.78%,4.22%）.（6）Wine sensory evaluation:Anti-transpiration has a significant effect on the taste and overall balance of Riesling,and the appearance is greatly different by year;had a significant effect on the clarity and color appearance of CS.The quality of the taste and the overall balance also been greatly improved in 2018;on the other hand,for CS and Riesling,anti-transpiration have different effects on the aroma quality.