棉花调亏灌溉的生理基础研究

以盆栽棉花为材料,通过苗期和现蕾期不同程度的亏水处理(低、中、高三个水平),对调亏灌溉节水效应及生理机制进行了研究。结果表明:适时适度的水分亏缺可使植株旺盛的营养生长得以有效控制,株型和根冠比都更为理想。调亏期间,蒸腾速率和气孔导度都明显下降,而光合速率下降不明显,复水后光合速率和气孔导度明显恢复且接近或高于对照;此外,水分亏缺不仅影响棉桃的数量,而且影响单果重。表明适度的亏水处理可使水分利用效率明显提高,而经济产量接近或高于对照,同时节水20%以上。

Physiology of growth control of cotton under regulated deficit irrigation

In the paper, the physiological and water-saving effects of Regulated Deficit Irrigation (RDI) on cotton were studied with pot-planting test under glasshouse. Controlled soil water deficit was applied with three moisture contents (low, moderate, high) at late seedling stage, budding stage or both stages. The results showed that, under appropriate water deficit in right stage, the excess vegetative growth was significantly inhibited, and the plant frame and root-shoot ratio were more ideal. During the water deficit period, the transpiration rate (ET) and stomatal conductance (g_s) of cotton leaves decreased obviously, but the diminution of photosynthesis rate (P_n) was not obvious. After re-watering, the P_n and g_s were significantly recovered to the level of the controls. In addition, the water deficit not only affected fruit numbers, but also affected per fruit dry weight. The final results showed that the yield of the proper RDI treatments was close to or higher than that of the controls, and that more than 20% of the irrigated water was saved.