| In this paper, precocious varieties’summer black’, late-maturing grape varieties’Red globe’ and ’Minicure Finger’ were used as material. With fruit sugar accumulation and sucrose metabolism as a starting point, to study the effect of "plastic mulch+greenhouse film" rain-shelter cultivation on ’Red globe’ fruit quality, sugar accumulation and related enzyme activities of sucrose metabolism; analysis the changes of sugar and acid and the relationship between sugar and sucrose metabolism related enzymes under rain-shelter cultivation of’summer black’grapes and’Minicure Finger’.The main results are as follows:1. A HPLC-ELSD method was developed to determine the content of sucrose, glucose and fructose in grape fruit. Using acetonitrile-water (78:22, V:V) as mobile phase with a flow rate of 1 mL/min., separation was performed on a prevail carbohydrate ES column (250 × 4.6 mm,5 μm). The drift tube temperature of evaporative light scattering detection and nitrogen flow rate were set at 50℃ and 1.5 L/min, separately. The developed calibration curves displayed good linearity over a concentration range of 1.0 μg to 50.0μg, with correlation coefficient exceeding 0.9996. With this method, sucrose, fructose and glucose achieved precision rates of 0.71%,0.92% and 0.96%, and stability rates of 1.8%, and 1.5% and2.7%, average recovery rates of 99.82%,98.17% and 98.47%, respectively. The method is convenient, free, and accurate of impurities interference with good separation and determination of sugars in grape fruits.2. Compared with open field cultivation, "plastic mulch+greenhouse film" rain-shelter cultivation does not change the double "S" growing curve model, but in favor of fruit development, improving the fruit quality. Furthermore,20～30 days after anthesis, the longitudinal diameter, transverse diameter, and fruit weight under rain shelter cultivation were significantly greater than that under open field cultivation. Also, Soluble solids and total sugar showed an increasing trend in both cultivation methods, the rate of increase was significantly higher than the total sugar soluble solids, in addition to 20-30 day after flowering, the soluble solids and total sugar fruits are cultivated under rain significantly greater than the open field. Matured, total soluble solid of ’red globe’ grape fruit under rain-shelter cultivation grew 16.91% than uncontrolled, total sugar increased by 15.84%. The titratable acids in grapes were almost at the same level under these two cultivation modes, which increased first and then decreased. Besides, within 20～40 days after anthesis, the ratio of total soluble solid content to titration acid and the ratio of sugar to acid in grapes increased equally and rapidly under these two cultivation modes. However, the ratio of total soluble solid content to titration acid and the ratio of sugar to acid in grapes cultivated under rain shelter were larger than those cultivated under open field.3. Our results indicated that with rain-shelter cultivation the sugar content and the activities of corresponding enzymes showed almost the same behavior during the development of fruit. Total sugar content of fruit produced under rain-shelter cultivation was higher than that of open field controlled fruit. The change of sucrose content of fruit affected by the shelter cultivation was the greatest. Our analysis manifested that the content of sucrose, fructose and glucose had significant relationship with the activity of NI and AI. The increase of sugar content is attributed to the increase of the activities of acid invertase and neutral invertase during the growing of berries under the environment of rain-shelter.4.’Red globe’,’Minicure finger’ and ’Summer black’ grape were double "S" curve of growth patterns and the presence of two rapid growth phases. The double "S" growing curve model of’Minicure finger’ and ’Red globe’are more apparent than the’Summer black’. Fruit ripening, the’Minicure finger’ grapes index of 2.07 was slim,’Red globe’ and ’Summer black’fruits index were 1.06 and 1.05, presented a round ball. Grape.fruit weight of ’Red globe’is significantly more weighty than’Summer black’, the soluble solids content of ’Summer black’is higher than the content of’Minicure finger’, the titratable acid content of ’Minicure finger’ grape is higher than’Summer black’.5.’Summer black’ and ’Minicure finger’ not because of the type of grape and fruit varieties and differences in developmental time change grapes mainly fructose and glucose accumulation type of sugar, but have an impact on each sugar component content and proportion. Although the activities of sugar metabolism-related were different, accumulating of sugar in the fruit of’Summer black’ and ’Minicure finger’, in the whole fruit development period, acid invertase and sucrose synthase activity has been high decomposition direction, sucrose phosphate synthase activity is low; sucrose content and sucrose phosphate synthesis activity was significantly and positively correlated with the acid invertase activity was significantly negatively correlated. So’summer black’ and ’beauty means’ grape fruit sugar accumulation of a key enzyme in the regulation are sucrose phosphate synthase and acid invertase. Fruit growth and development is the result of the accumulation of sugar sucrose metabolizing enzymes together. |
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