Effects of water stress at different growth stages on leaf physiological changes and fruit development of grape in greenhouse

Gansu Hexi Corridor is one of the main grape producing areas in China. In recent years, the greenhouse cultivation improved the price of table grape and farmers income. However, as a high water demand economic crop, grape has been affected by drought in Hexi Corridor. The key to solve the contradiction between grape planting and shortage of water resources is to promote the water-saving and efficient production mode of grape cultivation. In order to explore the efficient water management mode and water-saving production of table grape in greenhouse, the experiment was conducted in a 6-year-old vineyard with water stress (the soil moisture was controlled at 55% to 75% of field water holding capacity) at budburst stage (its duration was 14 d), shoot elongation stage (its duration was 20 d), flowering-fruit bearing stage (its duration was 11 d), fruit enlargement stage (its duration was 72 d), and coloring maturity stage (its duration was 97 d), respectively; while the other stages was at full irrigation (the soil moisture content was up to 75%-100% of field water holding capacity). And the full-irrigation during the whole growth period of grape was set as the contral treatment (CK). The activity of superoxide dismutase (SOD), contents of malondialdehyde (MDA) and proline (Pro), as well as fruit diameter, hardness of fruit, single fruit weight and yield were observed, which were used for study the response mechanism of grape leaf physiology and fruit yield to water stress. The results showed that the SOD activity and Pro content of grape leaves were significantly reduced by water stress at fruit enlargement stage and coloring maturity stage. The MDA content of grape leaves was also significantly increased by water stress during the above two long growing stages, which had a negative effect on grape leaves. The water stresses at budburst stage, shoot elongation and flowering-fruit bearing stages had no significant effects on SOD activity and Pro content of grape leaves, significantly impacted MDA content of grape leaves. The yield under water stress at fruit enlargement stage was 14 830 kg·hm^-2, which decreased by more than 20% compared with CK, and treatments of water stress at budburst stage and shoot elongation stage. Therefore, the water stress during fruit expansion stage in greenhouse significantly decreased SOD activity and osmoregulation substances contents, increased MDA content, and led to yield decrease of grape. In Gansu Hexi Corridor, it was not suitable to apply water stress at fruit expansion stage for greenhouse grape. The water stress in the early growth period had no significant effect on the physiology of grape leaves and fruit.