Effect Of Different Levels Of Phosphorus Nutrient On The Physiological Characteristic And Yield Of Rice Under Low Temperature Stress

In this study, we combined mid-long-term and short-term low stress temperature to study the effect of different levels of phosphorus nutrient on the physiological characteristic and yield of rice under low temperature stress. We determined MDA content, soluble sugar content and other biochemical indexs, some photosynthesis-related physiological indexs such as chlorophyll content, Fv/Fm, Pn, and dry matter accumulation, yield components and yield in the mid-long-term test; and compared the relatively effect rate of the physiological indexs and yield in the short-term test. What I have done is to provide a theoretical basis for chilling defense.The mid-long-term low temperature test showed that: the higher levels of phosphorus nutrient can increase the soluble sugar content, proline content, CAT activity, and decrease the content of MDA; the effect of SOD activity and POD activity are both different between varieties: Changbai9 SOD activity increased with the increase of phosphorus level increased, Jijing81 is first increased and then decreased slightly, and reached the maximum when 120kg/hm~2; phosphorus nutrient can increase the POD activity of Changbai9, but the situation is opposite of Jijing81. Some photosynthesis-related physiological indexs such as chlorophyll content, chlorophyll a/b, Pn maintain at a higher level under mid-long-term low temperature stress; the higher levels of phosphorus nutrient can increase Fv/Fm and qP , but the effect of NPQ activity are different between varieties: phosphorus can increase the NPQ of Changbai9, but decrease the NPQ of Jijing81. Phosphorus nutrient can increase the dry matter accumulation and matter conversion rate of fulling heading stage and maturity stage, and affect Changbai9 greater. The higher levels of phosphorus nutrient can increase the effective panicles of rice, grains per panicle, seed setting rate, 1000-grain weight, and impacted of effective panicles and 1000-grain weight significantly, but had little effect on the seed setting rate, and the yield of two varieties both became to maximum value at the 160kg/hm~2 under mid-long-term low temperature stress.The short-term low temperature test showed that: increased the phosphorus nutrient can decrease the effect of chlorophyll content, chlorophyll a/b, Pn. Fv/Fm, qP and NPQ; grain weight increased considerably as the level of phosphorus nutrition increased while the effect of seed setting rate increased slightly; the treatments of 14d of Jijing81, 7d of Changbai9, 14d of Changbai9 all came to the minimal damage, and yield to the highest at 160kg/hm~2; for the treatment of 7d of Jijing 81, the best phosphorus nutrient is 120kg/hm~2, at this level, the physiological indexs of chlorophyll content, Pn, Fv/Fm, qP, grains per spike, 1000-grain weight were impacted to the lowest, so is the yield.Phosphorus can ease the impact of low temperature on rice, and the cold tolerance of Changbai 9 was improved significantly with the phosphorus nutrient increase.