氮胁迫对不同株型水稻品种生理生化特性的影响

以穗型直立的紧凑型品种沈农07425和穗型弯曲的松散型品种秋光为材料,从不同施氮量对两水稻品种抗氧化酶活性和细胞膜伤害的影响两个方面研究氮胁迫对水稻生理生化特性的影响。结果表明:两品种叶片丙二醛含量随着水稻生育期的推进不断增加,这种增长趋势在松散型品种秋光上表现更为明显,各处理间丙二醛含量为低氮、高氮处理大于中氮处理。两株型品种的叶片CAT、SOD活性在测定时期内呈现降低的趋势,且这种趋势在紧凑型沈农07425上表现更突出,而叶片POD活性随着生育进程的推进小幅上升,至灌浆15d达到最大值,之后慢慢下降。两品种叶片SOD、POD、CAT活性均呈现高氮中氮低氮的关系。因此,在土壤N0.1~0.2g·kg-1,增施氮肥能提高保护酶活性,提升植物体内清除自由基的能力,延缓叶片衰老。MDA含量、POD活性可作为选择生育后期活性强、衰老慢品种的依据,以期获得较高的产量及氮肥利用率。

Effect of Nitrogen Stress on Physiological and Biochemical Properties of Different Types of Rice

The compact rice with erect panicles,Shennong 07425,and the loose rice with curved panicles,Akihikari,were used to study the effect of nitrogen applications on thephysiological and biochemical properties of the different types of rice plants.Activities of antioxidant enzymes and damages occurred to thecell membranes of the plants were the criteria used for the evaluation.It was found that MDA inthe leaves of both varieties elevated as the plants aged,and it was more apparent on Akihikari.In addition,either low or high nitrogenlevel resulted in a higher MDA content than those in between.Both varieties,especially Shennong 07425,exhibited a downward trend on CAT and SOD activities with increasingnitrogenapplications.The leaf POD activityrose slightly as theplant grew,reached a peak 15 days after grouting,andended with a gradual decline.The enzymatic activities were more significantly affected by high than low nitrogenlevels.Consequently,it was concluded that a nitrogen fertilization in the range of N 0.1-0.2 g · kg-1 would enhancethe activities of the protective enzymesin scavenging free radicals delaying senescence of leaves on the plants.Furthermore,theMDA content and POD activity of a rice variety could be used as an indicator in selecting and/or breeding a high-yieldcultivar with an efficient nitrogen utilization capability.