Abstract: In order to screening the appropriate coverage way with good water retention, anti-reversibility of grapes and effect of promoting fruit growth, the response of the protective enzyme (SOD, CAT) activity, osmoregulation content (Pro) content and membrane lipid peroxide (MDA) content and physiological indexes in greenhouse grapes and grape fruit to surface mulching were studied. The main results showed that, in the whole growth period, sand mulch, straw mulch, straw plus white plastic film mulch and straw plus black plastic film mulch presented the significant effect of water retention under the soil layer in 0 to 40 cm, and the water retention capacity of the straw plus black plastic film mulch was strongest (the soil water content increased by 14.53%, compared with that of no cover, P<0.05), and the water retention capacity of different mulching ways increased with the deepening of the soil layer, grape cells had the highest antioxidant levels under straw plus white plastic film mulch. Free Pro content significantly (P<0.01) improved in fruit under the sand mulch (it increased about 42.40% compared with no cover), and was advantageous to the maintenance of strong osmotic regulation ability, but, Pro generation was few under straw mulch. Grape fruit grain size was the largest under the sand mulch, however, the grape fruit grain size of straw+plastic film mulch, straw mulch were less than that of no cover treatment. Therefore, straw mulch increased moderately soil moisture, but reduced the water absorption ability of the cells, and inhibited the growth of the fruit. Straw plus white plastic film mulch significantly promoted the accumulation of soil moisture, prompted plentiful production of antioxidant enzymes, and fully protected the cells from reactive oxygen species, but it affected negatively the growth of grape fruit. The straw plus black plastic film mulch had the best effect of water retention and proper effect for maintaining the integrity of the cell, but the fruit promotion efficiency of it was not obvious. It was confirmed in study that sand mulch had significant promoting role in grape fruit, and has a certain water retention capacity and favorable ability of balancing the water metabolism of cell. Therefore, sand mulch was used as the best mulch way increasing water content, protecting cell membrane lipid and increasing fruit grain. The conclusion can provide the theory basis for the water-saving production mechanism of cultivation in grapes under surface mulching.

Key words: grape, surface cover, physiological indexes, water retention, resistance