抽穗期干旱复水对机插水稻抗氧化酶活性及根系活力的影响. (Chinese)

【Objective】To study the effects of drought rewatering at heading stage on antioxidant enzyme activities and root activity of rice varieties，and to explore the physiological mechanisms of the differences in drought resistance among different rice varieties，with a view to providing theoretical references for the selection of drought-resistant varieties and the study of high-yield rice.【Method】Eleven rice varieties commonly used in southern rice areas were used as test materials. Trenching was used to release water at the heading stage，and it was naturally dried for drought treatment. When the soil water content reached 50%-60% of the saturated water content，the ditch was filled with 2-3 cm water after rehydration treatment，samples were taken 3 d after to determine chlorophyll content，antioxidant enzyme activity，malondialdehyde（ MDA）content and root vitality. The differences in physiological characteristics among varieties were compared， and correlation analysis and clustering were performed.【Result】The chlorophyll content of leaves of different varieties at heading stage was different，and the difference of chlorophyll a was the most obvious. The chlorophyll a content of the variety Liangyouzao 17（4.59 mg/g）was the highest，followed by Zhongjianuo（4.30 mg/g）. The cultivars Zhongjiazao 18 and Xiangzaoxian No.32 had strong activities of superoxide dismutase（SOD）and peroxidase（POD），but their MDA content was also high，which may be affected by environmental stress. The order of root activity of 11 rice cultivars under drought rewatering at the heading stage was Liangyouzao 17>24d61>Luliangyou 996>Zhongjianuo>Xiangzaoxian No.32> Zhenguiai No. 1>24d44>Xiangzaoxian No. 24>Zhongjiazao 18>Zhuliangyou 819>zhongzao 39. Correlation analysis results of various physiological indexes of leaves showed that root vigor was significantly positively correlated with total chlorophyll content of leaves（P<0.05），and negatively correlated with antioxidant enzyme activity. The results of cluster analysis showed that the 11 rice varieties could be divided into three major categories. The first type was drought-sensitive and included six varieties with low root vigor and chlorophyll content，which were 24d44，Zhuliangyou 819，Zhongzao 39，Xiangzaoxian No.24，24d61 and Xiangzaoxian No.32，respectively. Type II was moderate drought resistance type including Zhenguiai No.1，Luliangyou 996 and Zhongjiazao 18. Type III was drought resistance type including Zhongjianuo and Liangyouzao 17，which had high photosynthetic pigment content and root vigor.【Conclusion】Root vigor and chlorophyll content are important indicators for selection of drought-resistant varieties. Liangyouzao 17 and Zhongjianuo are drought-resistant genotypes，which are suitable for promotion in the hilly and water-scarce areas of southern China. [ABSTRACT FROM AUTHOR]

【目的】研究抽穗期干旱复水对机插水稻品种抗氧化酶活性及根系活力的影响，探讨不同水稻品种间抗旱 性的差异，以期为抗旱品种筛选及水稻高产机制研究提供理论参考。【方法】以南方稻区常用的11份水稻品种为试验 材料，抽穗期采用开沟放水、自然落干方式进行干旱处理，待土壤水含量降至土壤饱和水含量的50%~60%时开沟灌 入2~3 cm水层进行复水处理，复水后3 d取样测定叶片的叶绿素含量、抗氧化酶活性、丙二醛（MDA）含量及根系活力 等指标，对比品种间的生理特性差异并进行相关性分析和聚类分析。【结果】不同品种抽穗期叶片的叶绿素含量存在 差异，主要以叶绿素a的差异最明显，其中两优早17的叶绿素a含量（4.59 mg/g）最高，其次为中佳糯（4.30 mg/g）。中 佳早18和湘早籼32号的超氧化歧化酶（SOD）和过氧化物酶（POD）活性较强，但其MDA含量也较高，可能受环境胁迫 的影响较大。抽穗期干旱后复水条件下11份水稻品种根系活力排序为两优早17>24d61>陆两优996>中佳糯>湘早 籼32号>珍桂矮1号>24d44>湘早籼24号>中佳早18>株两优819>中早39。叶片各生理指标的相关性分析结果表明， 根系活力与叶片总叶绿素含量呈显著正相关（P<0.05），与抗氧化酶活性呈负相关。聚类分析结果表明，11份水稻品 种可分为三大类，第Ⅰ类为干旱敏感型，分别为24d44、株两优819、中早39、湘早籼24号、24d61和湘早籼32号，该类型 的根系活力和叶绿素含量较低；第Ⅱ类为中度抗旱型，包含珍桂矮1号、陆两优996和中佳早18，该类型总叶绿素含量 较低但根系活力较强；第Ⅲ类为抗旱基因型，包括中佳糯和两优早17，该类型具有较高的光合色素含量和根系活 力。【结论】根系活力和叶绿素含量是抗旱品种筛选的重要指标，其中两优早17和中佳糯是抗旱基因型品种，适合在 我国南方丘陵缺水地区推广种植。 [ABSTRACT FROM AUTHOR]

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