Physiological Mechanism Of Water Use Efficiency In Hybrid Between Sorghum And Sudangrass

This experiment explored forage crop physioecological characteristics and water use efficiency from 2004 to 2005 under different soil water content and different cultivation measure. The results could be theoretical fundament for water use efficiency cultivation in gaodan grass .The main results are as follow:Different type gaodan grass had remarkably difference in water use efficiency .Its water use efficiency was Gaodan grass 1 number>forage sweet sorghum>Jian Bao. Under different water supply, the water use efficiency presented a quadratic curve with the dynamic of photosynthetic rate. The relationship between the photosynthetic rate and the transpiration rate presented a parabolic curve. There was a critical value of the transpiration at the maximal photosynthesis; it was luxurious if the transpiration value was above it. It is possible that taking some actions for increasing stomatic resistance and preventing transpiration could save water and improve photosynthesis and yield as well. The increase of temperature promoted the photosynthesis and transpiration and favored of leaves water use efficiency.Under different cultivated measure, stomata conductance had not remarkably augment with increase of nitrogenous fertilizer, but leaves of photosynthetic rate had been obviously advanced and its water use efficiency had been enhanced. The increase of phosphoric fertilizer could offset the harm of drought stress on plant upgrowth and metabolize active and enhance output and water use efficiency of plants. The function of Tectorial mostly manifests generational prophase. It could enhance upgrowth of gaodan grass in order to saving water and gaining yield.