STUDY ON ANTIOXIDANT ENZYMES OF AFFECTING GREENHOUSE GRAPE BERRY UNDER SURFACE MULCHING.

A field trial was designed by five mulching approaches (TS, coarse sand mulching; TJ, straw mulching; TBJ, straw mulching with white plastic film; THJ, straw mulching with black plastic film; TK, no mulching) for determination of main physiological factors affecting greenhouse grape berries, and mastery of how the grape berry was influenced particularly by antioxidant enzymes. Main results showed that: (1) the first eigenvalues of the three main factors in all treatments were above 1, which corresponded with the vanance ratio of TK>TJ>TS>TBJ>THJ, wherein TK was up to 95.634%, and THJ was 91.567%. In TS, higher load of 0.926, 0.834, and 0.638 occurred in catalase (CAT), Pro content in leaves and superoxide dismutase (SOD) activity of berries, of which correlation coefficient in principal component expression was 0.542, 0.526, and 0.618, respectively, serving as main component factors; (2) determination coefficient (R²) of berry diameter was in range of 0.970- 0.970, with high reliability. Based on linear regressions between the berry diameter and principal component factors, the interpretation degree of these principal components factors to the grape berry was 82.90%, 78.40%, 66.60%, 77.00% and 70.30% in TS, TJ, TBJ, THJ and TK, respectively. Our conclusions suggested that under coarse sand mulching, the high level of CAT activity reduced the effect of variational proline (Pro) content and SOD activity on grape berry. The complementary synergy effect of CAT, SOD and Pro promoted the grape berry growth; after straw mulching, the Pro content in grape leaves and berries kept at an unstable status in the middle phase of growing season, weakened the ability of maintaining leaf osmotic potential, led to grape berry was controlled by the malondialdehyde (MAD) accumulations; under straw mulching with black film, combining the higher SOD activity which was not affected by the growing season with more Pro content maintained the defensive capability of membrane system, furthermore, MAD with a gentle decrease in earlier growing season enhanced the resistance of grapevines. [ABSTRACT FROM AUTHOR]