| The glycomic acid fraction is one of the most important indexes for evaluating the edible value of fruits.In this study,high-performance liquid chromatography was used to develop glycomic acid composition analysis of 301 grape accessions stored in Zhengzhou National Grape Germplasm Repository,Zhengzhou Fruit Research Institute,Chinese Academy of Agriculuture Sciences,and to summarize the pattern of the gluconic acid composition of grape berries using cluster analysis and principal component analysis,to clarify the distribution pattern of its fruit glycolic acid composition,to screen excellent grape accessions,and to provide a theoretical basis for the conservation and utilization of grape resources.At the same time,the sugar acid changes of nine grape accessions at different development periods were explored,and the distribution and accumulation of the sugar acid components in different grape berries were preliminarily and clearly understood.The main results are as follows:（1）Study on the changes of sugar and acid in grape berries during growth and developmentIn grape berries,sugars mainly accumulate in the late stage of fruit development,with low levels in the pre stage and a rapid rise during the middle to late stages.The S3 period is a critical stage during grape fruit development and marks the beginning of the fruit ripening period,when sugars in the fruit begin to accumulate rapidly and organic acids begin to degrade,after S5,the accumulation of sugars slows and the acid components are also largely unchanged;Glucose and fructose rapidly accumulated at a ratio of 1:1 throughout fruit development,and the fructose content was slightly higher than that at fruit maturity（S5 stage）.During the whole fruit development period,malic acid and tartaric acid were the most dominant organic acids in grape fruits,and they gradually decreased with the growth and development of fruit,both tartaric acid and malic acid showed a first slow decline,then a rapid decline change trend,while the content of citric acid showed a first rapid decline and then a slow decline change trend.（2）Soluble sugar fractions and contents of ripe grape berries from different accessionsThe soluble sugars in grape fruits are mainly composed of glucose,fructose and sucrose,among which fructose has the highest content.Among 301 grape accessions,the range of total sugar content in grape fruits was from 75.98 mg/m L（Cabernet Sauvignon）to 229.45 mg/m L（N43-3）;The sweetness values of 94.35% accessions varied in the range of 120-270;78.07% of the accessions had higher fructose content than glucose,2.00% of the accessions had glucose content comparable to that of fructose（≤1 mg/m L difference between the two）,and another 19.93% of the accessions had higher glucose than fructose.The glucose content of Shen Nong Xiang Feng berries was very close to that of fructose,and only 0.06% differed between them.The variation of sucrose content was large and ranged from 0-28.11 mg/m L.Twenty seven accessions,including Black Wine,Riesling,and Sunshine Rose,were excellent resources for their fructose content and sweetness values.Accessions such as Cabernet Sauvignon,French Blue and Red Ruibao are excellent resources for high fructose and glucose.The sucrose content of Jintian Jadeite was the highest at 28.11 mg/m L among301 accessions,which could be utilized as a high sucrose parent.（3）Organic acid composition and contents of ripe berries from different accessionsThe organic acids in grape fruits were mainly constituted by tartaric acid,malic acid,citric acid and oxalic acid,of which tartaric acid was the highest.The differences of tartaric acid among the berries of 301 grape accessions were small,while the differences of oxalic acid,malic acid and citric acid were large;tartaric acid and malic acid were the most dominant organic acids in grape fruits,and the variation ranged from 1.54-12.67 mg/m L and 0.33-9.88 mg/m L,respectively,with the highest tartaric acid content of the germplasm being Vitis amurensis N43-3 and the highest malic acid content being Laojunshan.93.02% of the grape accessions,and the content of tartaric acid was higher than that of malic acid;2.32% of the accessions had a malic acid content comparable to that of tartaric acid（difference between the two ≤ 0.20 mg/m L）;There were 4.66%accessions with higher malic acid content than tartaric acid;Another 5.12% of the accessions had a malic acid content comparable to that of citric acid（difference between the two ≤ 0.10 mg/m L）.The cultivated grapes followed the rule that tartaric acid content was greater than malic acid;While the content of malate was higher than that of tartaric acid in wild grape species（except Vitis davidii Foex）,which was 1.2-1.7times higher than that of tartaric acid.Inter sample coefficients of variation were small for tartaric acid,total acid content and acidity values;The contents of oxalic acid,malic acid and citric acid varied greatly among samples.The organic acid contents of wild species grapes are much higher than those of cultivated species,especially N43-3,which is a endemic East Asian species with the highest organic acid content,so it can be treated as a superior organic acid quality to breed and utilize. |
