Effect Of Water And Potassium Coupling On Drought Resistance Characteristics And Changes Of Water And Potassium In Soil And Yield And Quality Of Flue-cured Tobacco

In this paper, water-culture experiment, Water-controlled experiment and field experiment were employed to study the effect of osmotic stress on drought resistance physiological indices and technology of water and potassium coupling in flue-cured tobacco. The results were showed as follows:1. Significant accumulation of proline (PRO) and soluble sugar (SS) in tobacco leaves was observed under osmotic stress. Notable increase of osmotic regulators was also found with the increasing of potassium supplying. The content of malondaldehyde (MDA) was increased significantly under osmotic stress, notable decrease of MDA content was found with the increasing of potassium supplying, which suggested that osmotic potential was improved with the increasing of potassium supplying, as well as the drought resistance of tobacco plant.2. The maximum leaf area, plant height, stalk perimeter, total leaf area and dry matter accumulation were increased to a certain degree with the increasing of potassium supplying. Changes of soil water within 0 to 20cm were most significant at every drought stage, decreasing of soil water was observed with the aggravation of drought, however, decreasing of soil water was restrained with the increasing of potassium supplying; Changes of soil water content within 20 to 40cm were much less, and soil water content was decreased with the increasing of potassium supplying with drought at root extending stage and maturing stage, while soil water content was increased at the vigorous growing stage. But changes of soil water content was not significant under 40cm depth soil layers. The models describing changes of soil water within different layers with time and potassium in drought stress were W=ae^bt, with which soil water content can be predicted. Changes of soil available potassium content were obviously within 0 to 20cm depth soil layer, but, it was affected with drought stress under 40cm depth soil layer at the vigorous growing stage and maturing stage. Soil available potassium content was decreased obviously within 0 to 20cm layer near to the...