低温对早稻幼穗分化期叶片生理特性的影响及其与产量的关系

Effect of low temperature stress on physiological characteristics of flag leaf and its relationship with grain yield during panicle primordium differentiation stage of early rice

  • 摘要: 为了探讨低温("小满寒")对早稻幼穗分化期水稻叶片生理特性及产量性状的影响, 本研究以30 ℃/ 25 ℃为对照, 利用人工气候室进行试验, 研究低温(22 ℃/17 ℃)下水稻叶片的生理生化变化特征, 并分析其与产量之间的灰色关联度。结果表明, 随低温处理时间的延长, 水稻光合色素呈先上升后下降趋势, 并在处理后4 d达最大值。水稻光响应曲线的最大光合速率、光饱和点及光能初始利用效率均随着低温胁迫时间的增加逐渐下降, 而光补偿点则呈上升趋势。在荧光参数方面, 光化学淬灭系数(qP)、PSⅡ电子传递效率(ETR)及PSⅡ最大光能转化效率(Fv/Fm)呈先下降后上升的趋势, 而非光化学淬灭系数(qN)则随着胁迫时间的延长于处理6 d达最大值。叶片SOD活性、POD活性、MDA含量和可溶性蛋白含量均呈先上升后下降的趋势, 而CAT活性随着胁迫时间的延长逐渐下降。另外, 水稻产量、穗长、结实率、成穗率及千粒重等均随低温处理时间的延长而减少。通过灰色关联度分析各个性状与产量之间的关联度, 依次为每穗实粒>穗长>二次枝梗数>一次枝梗数>千粒重>CAT活性, 且其关联度均大于1。CAT活性、光能初始利用效率、光饱和点、ETR、Fv/Fm及叶绿素a/叶绿素b等生理生化指标也与产量关联度较高, 可作为低温影响下产量评价与估算的指标。

     

    Abstract: The effects of low temperature stress on physiology and yield characteristics of early rice in Jiangxi Province as driven by artificial environmental controls were studied in this paper. The paper also analyzed the relationship of physiological characteristics and yield components with yield of early rice under low temperature (22 ℃/17 ℃) in the study area with gray correlation analysis. The normal daytime temperature in the region was 30 ℃ and that of night time was 25 ℃. With prolonged low temperature treatment, chlorophyll a, chlorophyll b and carotenoids contents of early rice leaves rose initially and dropped later. Maximum photosynthetic rate, light saturation point and initial light use efficiency tracked a downward trend according to photosynthetic light response curves. Light compensation point was apparently on the rise. Fluorescence parameters of qP, ETR, Fv/Fm had an early-increasing/later-decreasing tendency. Conversely, qN reached its maximum value after low temperature stress for 6 d. While activities of SOD, POD and contents of MDA and soluble protein had an early rise and later drop, CAT activity followed a declining trend. Yield, spike length, seed setting rate, spike rate, grain weight and other yield traits followed a decreasing tendency. Based on gray correlation analysis, in relation to yield, the rank of correlation degree was as follows: grains per panicle > spike length > secondary branch number > primary branch number > 1000-kernel weight > CAT, and the correlation degrees of these traits were all greater than 1. The physiological traits, such as initial light use efficiency, light saturation point, ETR, Fv/Fm, chlorophyll a/chlorophyll b also had greater correlation with early rice under low temperature. These physiological traits could be used as indicators to evaluate early rice yield under low temperature stress.

     

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