Submergence tolerance in relation to variable floodwater conditions in rice
Submergence tolerance in relation to variable floodwater conditions in rice
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DOI：
10.1016/j.envexpbot.2009.02.015
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发表时间：
2009-09-01
影响因子：
5.7
通讯作者：
Ismail, Abdelbagi M.
中科院分区：
文献类型：
--
作者：
Das, Krishna Kaveri;Panda, D.;Ismail, Abdelbagi M.
山洪暴发对南亚、东南亚和热带非洲大片雨养低地的水稻产量造成不利影响。已确定耐淹1-2周的地方品种；然而，由于耐性表型和洪水条件的复杂性，以及随后在不同环境中的表型鉴定遇到的差异，通过常规育种方法将耐性纳入现代高产品种的速度一直很慢。设计有效的表型策略需要彻底了解洪水的具体特征，这些特征最有可能影响洪水期间的存活率。我们调查了由人工遮荫、季节变化或水体浑浊引起的洪水温度和透光率对淹水后幼苗存活的影响。以耐淹水稻品种FR13A和Kusuma(耐淹)、Gangasiuli(中稻)、Sabita、CRK-2-6和Raghukunwar(拉长/避水型)和IR42(敏感)为材料进行了3个田间试验。我们测试了这样的假设，即较暖的洪水会降低植物的存活率，浑浊的水会通过减少透光率而造成与遮荫相似的影响，从而增加植物的死亡率。当水较冷时，植物存活得更好，水温高于26摄氏度时，单位水温每增加约8%，植物的存活率就会下降约8%。较低的光照强度和较暖的温度似乎会减少生物量，增加洪水下的死亡率。O-2浓度的增加。二氧化碳和水中pH的降低并不能提高它们在清澈无阴影的水中的存活率。浑浊的洪水对水稻的伤害更大，因为植株死亡率随着泥沙含量的增加而增加，而水浑浊的影响不能仅用抗渗性的降低来解释。即使是耐性最强的水稻品种FR13A，在被浑浊的洪水淹没时，也会经历更高的死亡率。相关研究表明，淹水后能够保持较高生物量、较高叶绿素和非结构性碳水化合物浓度的品种具有较高的存活率。这些发现有助于理解在不同环境下进行筛选时观察到的耐浸水能力的差异。这项研究可能对设计适当的筛选策略和评估不同水稻种植区被淹造成的损害具有一定的意义。(C)2009爱思唯尔B.V.保留所有权利。
Flash floods adversely affect rice productivity in vast areas of rainfed lowlands in South and Southeast Asia and tropical Africa. Tolerant landraces that withstand submergence for 1-2 weeks were identified; however, incorporation of tolerance into modern high-yielding varieties through conventional breeding methods has been slow because of the complexity of both the tolerance phenotype and floodwater conditions, and the ensuing discrepancies encountered upon phenotyping in different environments. Designing an effective phenotyping strategy requires a thorough understanding of the specific floodwater characteristics that most likely affect survival during flooding. We investigated the implications of floodwater temperature and light penetration, caused by artificial shading, seasonal variation, or water turbidity, for seedling survival after submergence. Three field experiments were conducted using rice genotypes contrasting in their tolerance of submergence: FR13A and Kusuma (tolerant); Gangasiuli (intermediate); Sabita, CRK-2-6 and Raghukunwar (elongating/avoiding types): and IR42 (sensitive). We tested the hypotheses that warmer floodwater decreases plant survival and that turbid water augment plant mortality by causing effects similar to those caused by shading, by reducing light penetration. Plants survive better when water is cooler, and survival decreased at about 8% per unit increase in water temperature above 26 degrees C. Lower intensity of light and warmer temperatures seem to reduce biomass and increase mortality under flooding. An increase in the concentrations of O-2. and CO2 and a decrease in water pH did not improve survival in clear unshaded water. Turbid floodwater was more damaging to rice as plant mortality increased as the percentage of silt increased, and the effects of water turbidity cannot be explained by the reduction in fight penetration alone. Even the most tolerant rice cultivar, FR13A, experienced higher mortality when flooded with turbid floodwater. Correlation studies revealed that cultivars with the capacity to maintain higher biomass, higher chlorophyll, and non-structural carbohydrate concentrations after submergence had higher survival. These findings help to understand the variation observed in submergence tolerance when screening is done under different environments. The study could have implications for designing proper screening strategies and assessing the damage submergence causes across different rice-growing regions. (C) 2009 Elsevier B.V. All rights reserved.