Effects Of Water Stress At Tillering And Heading Stage On The Physiological Characteristics Of Rice

China is the largest producer of rice in the world, but due to the shortage of water resource in our country, rice irrigation water consumption accounted for65%of the total amount of water use, it is necessary to research into the regularities of water requirement of rice for the development of water-saving agriculture. This project took Gui Liang You2as material, and the PEG simulated water stress pot experiment was conducted in the early season of2012and the soil pot experiment in late season. The results show that:1In the PEG simulated water stress experiment, the grain yield, after the rice went through the tillering stage, mild water stress, was higher4.16%than that of the control, and grain yields with other kinds of water stress were lower than that of the control, grain yield of extremely severe water stress was the most serious, decreased by24.54%compared with that of the control. The grain yield, under a normal water stress at heading stage condition was the highest, The grain yield of T4and T5water treatment was significantly decreased by20.79%and22.45%respectively. With regard to the soil pot experiment, the grain yield would reach its summit under the circumstance that the solid water content which accounted for90%to100%of the saturated water content in both tillering and heading stages.2With PEG simulated water stress, during water stress of tillering stage, the water treatment of T2and T3at tillering stages was beneficial to root growth. After re-watering, root growth of water treatment was not different with that of the control. Root growth had little effect on all kinds of water stress of heading stage, after re-watering, root growth of T2and T3were more developed than that of the control, both tillering and heading stages, root activities were stimulated by water stress and root activity of rice still maintain higher after re-watering. Root activity of T4treatment at tillering stage was highest, and1.45times higher than that of the control, root activity of T2treatment at heading stage was highest and1.92times higher than that of the control. With the soil culture and water control at tillering and heading stage, the root growth of W1was the fastest in both of the two stages.3The nitrogen dry matter productivity could be improved and nitrogen harvest index be decreased under water stress condition. The nitrogen grain productivity under normal water stress condition at tillering stage is the highest; nitrogen grain productivity with light and moderate water stress at heading stage was higher11%and1.7%than that of the control.