酸化土壤对不同晚稻品种氮素利用效率的影响机制研究

发布时间：2019-04-04 19:44

【摘要】：酸化上壤直接影响水稻根系与土壤酶类和微生物类群,从而影响到水稻地上部分的生长发育及产量。本研究基于前两年的研究结果,以不同酸性敏感性双季晚稻品种为材料,通过酸化稻田对比试验和盆栽模拟酸化试验,比较了不同土壤pH条件下不同双季晚稻品种的农艺性状、产量、氮素积累量和利用效率,研究了酸化土壤条件下的双季晚稻光合特性、根系形态和根系生理特性及上壤生物学特性,探讨了其与晚稻氮素利用效率的相关性,旨在研究酸化土壤对不同晚稻品种氮素利用效率的影响机制。主要结果如下：(1)酸化稻田上,3种酸性敏感类型的晚稻品种生育期均延长5-7d,分蘖数、株高、叶面积指数、光合速率与干物质积累量均下降。酸性敏感型和酸性迟钝型品种千粒重、有效穗数、产量随土壤pH值降低而降低,酸性敏感型品种产量降低了2.02%-24.55%,酸性迟钝型品种产量降低了9.18%-10.56%。酸性特异型晚稻品种产量随pH值降低而提高。(2)水稻植株地上部分各部位的氮积累量受到土壤pH值的影响,酸化稻田上3种酸性敏感类型的晚稻品种植株各部位的氮积累量与总氮积累量一般均呈增大趋势,但稻谷氮素生产效率、氮收获指数和氮生理效率等指标均随之下降,且一般均表现出极显著性差异。(3)盆栽模拟酸化试验结果表明：与pH6.5处理相比,pH3.5处理水稻根系体积、根干重和根含氮量均明显减少,根系总吸收面积和活跃吸收面积降低,根系活跃吸收面降低50%-66.7%,根系3大保护酶(SOD、POD和CAT)活性升高,根系硝酸还原酶活性降低。(4)稻田酸化试验和盆栽模拟酸化试验结果表明：当土壤pH值从6.5下降到5.2时,土壤过氧化氢酶、蔗糖酶和脲酶活性均降低,土壤微生物类群也随之发生变化,细菌、放线菌、真菌与原生动物均减少。(5)相关性分析表明,叶片的净光合速率、气孔导度和蒸腾速率与氮素利用效率呈正相关,叶片胞间CO2浓度、叶绿素相对含量与氮素利用效率呈负相关。根系总吸收面积、活跃吸收面积、活跃吸收面积百分率与氮素利用效率呈负相关,根系可溶性蛋白、根系SOD、POD、CAT活性与氮素利用效率呈负相关,根系活力与氮素利用效率呈正相关,根系硝酸还原酶活性与氮素利用效率呈显著负相关,根系形态特征如根体积、根干重、根冠比及根系含氮量与氮素利用效率呈正相关。土壤中过氧化氢酶、蔗糖酶和脲酶活性,土壤中细菌、放线菌、真菌、原生动物数量与氮素稻谷利用效率、氮收获指数和氮生理效率等氮利用效率指标均呈显著或极显著正相关。可见,酸化土壤影响晚稻的氮素利用效率主要是通过影响土壤过氧化氢酶、蔗糖酶和脲酶活性,细菌、放线菌、真菌和原生动物数量,其次是根系硝酸还原酶活性、根冠比和根系含氮量来影响晚稻氮利用效率的。
[Abstract]:The acidified soil directly affects the root and soil enzymes and microbial groups of rice, thus affecting the growth and development of the above-ground part of rice and the yield of the above-ground part of rice. Based on the results of the previous two years, the agronomic characters of two-crop late rice varieties with different acid sensitivity were compared under different soil pH conditions through comparative experiments in acidified rice fields and simulated acidification experiments in potted plants. Yield, nitrogen accumulation and utilization efficiency of late rice were studied in this paper. The photosynthetic characteristics, root morphology and physiological characteristics of roots and biological characteristics of upper soil were studied under acidified soil conditions, and the correlation between nitrogen use efficiency and nitrogen use efficiency of late rice was discussed. The effects of acidified soil on nitrogen use efficiency of different late rice varieties were studied. The main results were as follows: (1) in acidified paddy fields, the growth period of three acid sensitive late rice varieties were prolonged by 5 ~ 7 days, the number of tillers, plant height, leaf area index, photosynthetic rate and dry matter accumulation decreased. The 1000-grain weight, effective panicle number and yield of acid-sensitive and acid-sensitive varieties decreased with the decrease of soil pH value, and the yield of acid-sensitive varieties decreased by 2.02% and 24.55%, respectively. The yield of acid-retarded variety decreased by 9.18% / 10. 56%. The yield of acid-specific late rice varieties increased with the decrease of pH value. (2) the nitrogen accumulation of above-ground parts of rice plants was affected by soil pH value. The nitrogen accumulation and total nitrogen accumulation of three acid sensitive late rice varieties in acidified paddy field generally showed an increasing trend, but the nitrogen production efficiency, nitrogen harvest index and nitrogen physiological efficiency of paddy decreased accordingly, while the nitrogen accumulation and total nitrogen accumulation of three acid sensitive late rice varieties tended to increase in general, but the nitrogen production efficiency, nitrogen harvest index and nitrogen physiological efficiency decreased accordingly. (3) compared with pH6.5 treatment, the root volume, root dry weight and root nitrogen content of pH3.5 treatment decreased significantly, and the results of pot experiment showed that: (1) compared with pH3.5 treatment, the root volume, root dry weight and nitrogen content of rice decreased significantly. The total absorption area and active absorption area of root decreased, the active absorption surface of root decreased by 50% / 66.7%, and the activities of three protective enzymes (SOD,POD and CAT) increased. The root nitrate reductase activity decreased. (4) when soil pH decreased from 6.5 to 5.2, the activities of soil catalase, sucrase and urease all decreased. (4) Paddy field acidification experiment and pot simulation experiment showed that soil catalase, sucrase and urease activity decreased when soil pH decreased from 6.5 to 5.2. Soil microbial groups also changed, bacteria, actinomycetes, fungi and protozoa decreased. (5) correlation analysis showed that net photosynthetic rate, stomatal conductance and transpiration rate of leaves were positively correlated with nitrogen use efficiency. There was a negative correlation between the intercellular CO2 concentration and chlorophyll relative content and nitrogen use efficiency. There was a negative correlation between root total absorption area, active absorption area percentage and nitrogen use efficiency, and a negative correlation between root soluble protein, root SOD,POD,CAT activity and nitrogen use efficiency. There was a positive correlation between root activity and nitrogen use efficiency, and a significant negative correlation between root nitrate reductase activity and nitrogen use efficiency. Root morphological characteristics such as root volume, root dry weight, root / shoot ratio and root nitrogen content were positively correlated with nitrogen use efficiency. The activities of catalase, sucrase and urease in soil, the number of bacteria, actinomycetes, fungi and protozoa in soil and the utilization efficiency of nitrogen rice. There were significant or extremely significant positive correlations between nitrogen harvest index and nitrogen utilization efficiency such as nitrogen physiological efficiency. The nitrogen use efficiency of late rice in acidified soil was mainly influenced by the activities of soil catalase, sucrase and urease, the number of bacteria, actinomycetes, fungi and protozoa, followed by root nitrate reductase activity. The ratio of root to shoot and nitrogen content in root affected the nitrogen use efficiency of late rice (Oryza sativa L.).
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511.33;S153

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