水稻抗旱生理及抗旱相关基因的研究进展

干旱缺水是影响水稻生长发育的重要逆境因子。干旱胁迫会诱导水稻特定基因表达，这些基因的表达和调控能使水稻抵御干旱胁迫的伤害。筛选和培育抗旱的水稻品种不但可在很大程度上节约用水，而且有利于增产稳产和减少环境污染。在此，简要概述了水稻抗旱生理、抗旱机制和抗旱相关基因一些进展，为提高水稻抗旱性和抗旱育种提供相关参考。     

水稻抗旱机理和抗旱育种研究进展

水资源短缺正成为制约中国水稻生产持续发展的重要因素,培育抗旱性强的水稻品种,不但能够节约水资源,而且有利于稳产增产、节约能源。日益深入的干旱胁迫响应基因及QTL定位研究的积累为进行抗旱育种提供了依据和基础。对水稻在干旱胁迫下的伤害机理和抗旱的分子机制以及水稻抗旱育种研究进展等方面进行了总结和综述,以期为今后进一步深入研究抗旱机理及抗旱育种提供理论依据。今后应加强对稻属抗旱基因资源的有效发掘、评价、创新和利用,进一步发挥抗旱分子标记辅助选择在抗旱育种实践中的作用,改良水稻根系,结合常规育种技术和现代生物技术,提高栽培稻的抗旱性。     

水稻抗旱生理生化及其相关基因研究进展

干旱胁迫是影响水稻生长发育的重要环境因素之一。水稻在干旱胁迫条件下,产生相应的生理变化并诱导特定相关基因的表达,这些生理变化与相关基因的表达减少了水稻在干旱胁迫条件下带来的伤害。选育抗旱新品种不但可以节约水资源,而且有利于提高水稻产量。该文对水稻抗旱生理生化机制和抗旱基因的最新研究进行阐述,为提高水稻抗旱性和抗旱育种提供理论依据。     

干旱对水稻生长发育的影响及其抗旱研究进展

水稻(Orazy sativa L.)是主要的粮食作物之一,又是耗水量最多的农作物,水资源短缺严重制约着水稻生产。本文综述了干旱对水稻生长发育的影响,以及水稻抗旱品种鉴定、抗旱育种和节水栽培等抗旱减灾措施的研究进展,以期为今后水稻抗旱性的深入研究提供参考。     

水稻抗旱性研究现状与展望

综述了水分胁迫对水稻的伤害以及水稻植株在气孔调节、渗透调节、激素调节、膜抗氧化保护酶类和干旱诱导蛋白等方面抗旱性生理生化机制的研究进展。介绍了水稻抗旱性状的基因定位和抗旱性基因工程方面的研究现状,并指出,稻属抗旱基因资源的发掘以及在育种上的遗传利用和水稻抗旱节水综合栽培技术的研究是当前研究的热点。     

植物旱害及抵御植物旱害途径的研究进展

综述了植物旱害类型;植物抵御干旱反应的途径;干旱伤害植物的机理以及植物抗旱的机制;农业上如何使用合理的栽培措施和化学物质避免干旱的危害.简述了常规育种技术和现代分子育种技术相结合选育优良抗旱高产品种的进展.为农业抵御和降低干旱危害,培育抗旱农作物品种提供参考.     

水稻生长对干旱胁迫的响应及抗旱性研究进展

水稻是我国主要粮食作物,也是用水量最多的作物.研究水稻抗旱性,培育抗旱水稻品种,实现水资源不足背景下水稻的高产和稳产,有助于缓和粮食生产与水资源短缺之间的矛盾.国内外学者对水稻抗旱机理、抗旱鉴定指标以及抗旱相关基因的分析等做了大量研究并取得了突破性进展.本文从形态特征、生理生化特性以及分子水平等方面综述了干旱胁迫对水稻生长的影响,全面了解水稻在干旱胁迫下的形态变化及其生理生化抗旱机制,以期为鉴定筛选抗旱种质、选育抗旱品种提供参考.     

保障粮食安全育种途径与创新研究

干旱、病虫害等自然灾害及生态环境日益严重,是全球密切关注的影响粮食安全的大问题.为保障我国粮食安全,提高作物抗灾能力、提出了抗病育种,抗旱育种及生物技术育种等作物育种途径及创新研究.     

推广水旱兼用抗旱杂交稻 促进南方稻区粮食生产的可持续发展

针对近年南方稻区夏、秋季持续高温、干旱灾害性天气的影响,提出推广水旱兼用抗旱杂交稻是稳定水稻种植面积,维护国家粮食安全的重要措施。同时,对国内外有关抗旱杂交稻种质创新与应用现状的最新动态进行简要介绍。     

植物抗旱生理研究进展与育种

植物在干旱胁迫下的生理代谢变化一直是抗旱生理的研究热点。植物为适应和抵御干旱环境所形成的形态特征和生理特性以及生理变化机制是一个复杂的系统。通过对部分抗旱生理生化研究进展的归纳和总结,主要从3个方面提出植物在干旱胁迫下的主要生理反应和生化变化指标。并通过比较分析,综述了在干旱胁迫下植物生理生化方面的反应和变化规律。从而为抗旱种质的鉴定、筛选和抗旱生理育种提供参考。     

Conventional and contemporary approaches for drought tolerance rice breeding: Progress and prospects

Drought is becoming a major threat to rice farming across the globe owing to the depletion of water tables in rice-growing belts. Drought affects rice plants at multiple stages, causing damage at morphological and physio-biochemical levels, leading to severe losses that exceed losses from all other stresses. The amalgamation of conventional breeding methods with modern molecular biology tools and biometrical methods could help accelerate the genetic gain for drought tolerance in rice. Many drought-tolerance traits with genetic determinants have been identified and exploited for tolerance rice variety breeding. The integration of genome-wide association study and genomic selection tools with speed breeding shortened the breeding cycle and aided in rapid improvement of genetic gain. In this review, we emphasized the progress made through classical breeding as well as the limitations and usefulness of current genomic methods in improving drought tolerance. We briefly addressed methods for identifying genetic determinants for drought tolerance and deploying them through genomics-assisted breeding programmes to develop high-yielding drought-tolerant rice cultivars.     

水分胁迫对水稻结实期一些生理性状的影响

选用抗旱性不同的3个杂交水稻品种，在干旱棚内分别在正常供水和水分胁迫条件下，研究了水稻结实期丙二醛（MDA）含量、光合速率、气孔导度、渗透调节物质及保护性酶活性等生理性状变化。结果表明，结实期随土壤水分胁迫加剧和时间延长细胞膜脂过氧化加剧，抗旱性弱的品种膜脂过氧化更为严重；剑叶光合速率、气孔导度和叶绿素含量迅速下降，抗旱性弱的品种比抗旱性强的品种降速快、幅度大。抽穗后0～14 d随胁迫时间的延长叶片内可溶性糖、氨基酸含量增加，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）3种酶活性升高，抗旱性强的品种增加或升高的幅度大。抽穗14 d后叶片内可溶性糖、氨基酸含量下降，SOD、CAT和POD酶活性降低。试验表明，水稻叶片MDA含量、光合作用、渗透调节物质及保护性酶活性的变化幅度与品种的抗旱性密切相关。     

夏季干旱期间贵州农业气候资源优劣分析

为定量评估夏季干旱期间光照、热量和水分农业气候资源对粮食作物的客观影响,采取粮食光温生产潜力、光温水生产潜力评估方法,对比分析夏季干旱期间粮食生产潜力相对于气候平均状态的偏差,客观定量地分析夏季干旱期间贵州农业气候资源优势和劣势。研究表明：夏季干旱背景下,贵州水稻、玉米光温生产潜力相对于正常气候年份普遍偏高10%左右,光照和热量资源优势明显;而水稻、玉米光温水生产潜力却普遍偏低30%~40%,水分资源劣势限制了作物生长。通过水资源的合理开发和高效利用,满足干旱期间农作物的水分需求,良好的光照和热量条件可更加有利于农业生产。     

Characterization of drought stress environments for upland rice and maize in central Brazil

Drought stresses arise when the combination of rainfall and soil water supply are insufficient to meet the transpiration needs of the crop. In the Cerrado region of Goiás state, Brazil, summer rainfall is typically greater than 1000 mm. However, drought stress can occur during rain-free periods of only 1–3 weeks, since roots are frequently restricted to shallow depths due to Al-induced acidity in deeper soil layers. If these droughts are frequent, then plant breeding programs need to consider how to develop suitable germplasm for the target population of environments (TPE). A crop simulation model was used to determine patterns of drought stress for 12 locations and >30 environments (6 years × 5–6 planting dates) for short and medium duration rice crops (planted in early summer), and for maize grown either as a 1st or 2nd crop in the summer cycle. Regression analysis of the simulations confirmed the greater yield impact in both crops of drought stress (quantified as the ratio of water-limited to potential transpiration) when it occurred around the time of flowering and early grain-filling. For rice, mild mid-season droughts occurred 40–60% of the time in virgin (0.4 m deep for rice or 0.5 m for maize) soils and improved (0.8 m for rice or 1.0 m for maize) soils, with a yield reduction of <30%. More severe reproductive and grain-filling stress (yield reductions of 50% for rice to 90% for maize) occurred less frequently in rice (<30% of time) and 1st maize crop (< 10% of time). The 2nd maize crop experienced the greatest proportion (75–90%) of drought stresses that reduced yield to <50% of potential, with most of these occasions associated with later planting. The rice breeding station (CNPAF) experiences the same pattern of different drought types as for the TPE, and is largely suitable for early-stage selection of adapted germplasm based on yield potential. However, selection for virgin soil types could be augmented by evaluation on some less-improved soils in the slightly drier parts of the TPE region. Similarly, the drought patterns at the maize research station (CNPMS) and the other maize screening locations are better suited to selection of lines for the improved soil types. Development of lines for the 2nd crop and on more virgin (acidic) soils would require more targeted selection at late planting dates in drier sites.     

东乡普通野生稻全生育期抗旱性鉴定

利用组合R974//东野/R974 BC₁F₅ BIL群体，设水分胁迫和非胁迫两种处理，在全生育期测定了株高、单株分蘖数、单株有效穗数、穗长、穗实粒数、穗总粒数、着粒密度、千粒重、结实率、单株产量、叶片相对含水量、卷叶级别等12个与抗旱相关的形态及生理性状，其中单株产量对水分胁迫影响最敏感。通过各性状旱、水相对值对抗旱系数分别进行单因素逐步回归、通径、灰色关联分析，结果表明，叶片相对含水量、单株分蘖数、穗实粒数、千粒重、株高、单株有效穗数等6个性状与水稻抗旱性相关显著，可作为全生育期抗旱鉴定指标。利用模糊隶属函数法对入选性状的抗旱D值进行抗旱性综合评价，更表明上述性状作为水稻全生育期的抗旱鉴定指标是可行的。同时对5种抗旱性评价方法进行比较指出，抗旱指数是最合适的抗旱性直接评价方法。     

水稻第2染色体上抗旱相关性状QTL的精细定位

水资源危机使得水稻抗旱性的遗传与育种研究成为当今的研究热点之一。鉴定与水稻抗旱性直接相关的性状和产量的QTL,可为通过标记辅助选择培育抗旱水稻品种提供标记信息。以从供体IRAT109渗入到珍汕97B背景的269个高代回交渗入系中筛选出覆盖第2染色体目标区段的87个近等基因系为材料,在抗旱鉴定大棚中采用控制式供水,精细定位了水处理(对照)与干旱胁迫条件下影响水稻水分生理及产量相关性状的QTL。共检测到20个影响叶水势(LWP)、冠层温度(CT)、茎基粗(BCT)等性状相关QTL和百粒重(HGW)、每穗颖花数(SN)、着粒密度(SPD)等产量相关QTL。根据在不同环境下的表达情况,将其分为3类,第1类7个QTL,在两种环境下均被检测到;第2类4个,只在对照条件下检测到;第3类2个,分别控制叶水势和颈基粗,受干旱胁迫诱导,只在胁迫条件下被检测到,其中,叶水势定位在RIO02037-RIO02038约8.2 kb的区段上, 其加性效应和贡献率分别为-1.0361和13.03%,增效等位基因来自IRAT109;茎基粗定位在RIO02017-RIO02022约37.7 kb的区段内,加性效应和贡献率分别为0.2682和49.20%,增效等位基因来自珍汕97B。在水、旱2种条件下均检测到的相对稳定的7个QTL及干旱胁迫条件下的2个QTL可能对抗旱性有直接贡献。     

水稻作物对重金属镉的积累、耐性机理以及栽培调控措施进展

为了更加深入研究水稻作物对土壤中镉的积累与毒害耐性机理、了解栽培调控措施对稻米安全生产的意义,本文归纳了水稻作物对镉的转运和积累,分析了水稻镉积累差异及其特征;总结了水稻作物耐镉胁迫的机制,从抗氧化系统,限制吸收和运输,螯合作用等方面分析了水稻对镉胁迫的耐性机制;从肥料、水分等方面分析了栽培措施对水稻镉吸收和积累的调控效应。提出了应加强污染预防品种的选育和栽培调控措施研究等工作的意见和建议。     

Root pulling resistance in rice: Inheritance and association with drought tolerance

Summary Avoidance of drought stress is commonly associated with root system characteristics and root development. The inheritance of root pulling resistance in rice (Oryza sativa L.) was investigated and its relationship with visual field scores for drought tolerance was studied. Transgressive segregation for high root pulling resistance was observed in 3 crosses (high x high, low x high, and intermediate x intermediate). Both dominant and additive genes control the variation. F₁ superiority for high root pulling resistance was observed and could be exploited in an F₁ hybrid breeding program. F₂ distribution curves indicated that plants highly resistant to root pulling can be obtained not only from low x high and high x high crosses, but also from intermediate x intermediate crosses. Root pulling resistance in rice has a low heritability (39 to 47%). Thus, breeding for a high root pulling resistance may best be accomplished by selection based on line means rather than individual plant selection. Field screening showed significant differences in leaf water potential among random F₃ lines. F₃ lines with higher leaf water potential had better visual scores for drought tolerance. Visual drought tolerance scores were correlated with root pulling resistance. Plants with high root pulling resistance had the ability to maintain higher leaf water potentials under severe drought stress. The usefulness of the root pulling technique in selecting drought tolerant genotypes was confirmed.