杂交水稻苗期耐淹涝特性及其与亲本的关系

经对生产上主栽的野败型三系杂交组合及其亲本苗期耐淹涝能力的比较研究，杂交稻的耐淹涝能力的平均优势明显，且以显性效应为主。恢复系效应大于不育系；杂交稻淹涝后生存率与恢复系呈极显著正相关，与不育系呈显著正相关。杂交稻的耐淹涝表现以偏父型和中间型为主（80％以上），偏母型比例低。恢复系、不育系耐淹涝能力强的，配出的杂交稻耐淹涝能力更强。     

外源一氧化氮对盐胁迫下水稻根部脂质过氧化的缓解作用

 在100 mmol/L NaCl的胁迫条件下，研究了两种浓度的一氧化氮供体硝普钠（sodium nitroprusside，SNP）处理对水稻幼苗根部脂质过氧化的影响。低浓度（10 μmol/L）的SNP处理明显缓解盐胁迫下水稻幼苗根组织膜脂过氧化产物MDA的累积，显著提高可溶性蛋白含量，并诱导根系APX、POD和SOD活性的上升；而高浓度（50 μmol/L）SNP处理的效果则基本相反。表明外源低浓度NO可以通过提高盐胁迫下水稻幼苗根组织的抗氧化能力来缓解氧化损伤。     

杂交稻与常规稻对涝渍环境适应能力的比较研究

利用形态和产量性状指标,比较分析了杂交稻和常规稻在分蘖期和孕穗期对淹涝胁迫环境适应能力的差异性。在深水涝渍条件下,杂交稻生长发育普遍快于常规稻,单蔸苗数显著高于常规稻,有效穗相对受害率低于常规稻,因而单蔸产量显著高于常规稻。分蘖期遭受淹涝胁迫杂交稻的忍耐力优于常规稻,淹涝后的活苗率显著高于常规稻;而且,受淹涝后的杂交稻比常规稻能更快地恢复生长,成熟时主要农艺性状表现是成穗率极显著高于常规稻,每穗实粒数和结实率的相对受害率极显著低于常规稻,单蔸产量的受害程度低于常规稻。孕穗期淹涝胁迫后,杂交稻和常规稻之间产量及相关经济性状的差异均未达到显著水平。     

淹涝胁迫对水稻生长发育危害与耐淹性机理研究的进展

评述了淹涝胁迫对水稻生长发育的影响、水稻耐涝的生理机制、淹涝胁迫的基因型差异和耐淹性遗传与减灾措施等方面的一些研究进展,并简要提出了今后的研究方向。     

淹水胁迫下水稻根尖细胞中Ca^2＋和Ca^2＋—ATP酶的分布

应用电镜细胞化学方法，对淹水胁迫下水稻根尖细胞中Ca^2 和Ca^2 -ATP酶分布的变化进行了观察。正常生长条件下，Ca^2 主要分布于液泡和细胞间隙中，而细胞质基质、细胞核中分布很少；Ca^2 －ATP酶主要分布于质膜上，线粒体膜、内质网膜、核膜上也有酶分布。经过没顶淹水处理后，液泡、细胞间隙中的Ca^2 沉淀颗粒明显减少，而胞质及核基质中的沉淀颗粒明显增多，同时，质膜及其他膜结构上Ca^2 －ATP酶的活性明显降低。淹水造成根尖细胞中Ca^2 －ATP酶活性降低，胞质和核基质中Ca^2 积累，将影响细胞的正常生理代谢活动。     

Impeded Carbohydrate Metabolism in Rice Plants under Submergence Stress

The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documented and clarified in the present investigation. It was found that photosynthetic rate and concomitant translocation of sugars into the panicles were both related to the yield. The detrimental effects of the complete submergence were recorded in generation of sucrose, starch, sucrose phosphate synthase and phosphorylase activity in the developing panicles of the plants as compared to those under normal or control (i.e. non-submerged) condition. The accumulation of starch was significantly lower in plants under submergence and that was correlated with ADP-glucose pyrophosphorylase activity. Photosynthetic rate was most affected under submergence in varying days of post-flowering and was also related to the down regulation of Ribulose bisphosphate carboxylase activity. However, under normal or control condition, there recorded a steady maintenance of photosynthetic rate at the post-flowering stages and significantly higher values of Ribulose bisphosphate carboxylase activity. Still, photosynthetic rate of the plants under both control and submerged conditions had hardly any significant correlation with sugar accumulation and other enzymes of carbohydrate metabolism like invertase with grain yield. Finally, plants under submergence suffered significant loss of yield by poor grain filling which was related to impeded carbohydrate metabolism in the tissues. It is evident that loss of yield under submergence is attributed both by lower sink size or sink capacity (number of panicles, in this case) as well as subdued carbohydrate metabolism in plants and its subsequent partitioning into the grains.     

抛秧立苗的根系特点及其对水稻生长的影响

 通过设置带土直立苗、带土倾斜苗、带土平躺苗、无土平躺苗、无土直立苗等不同苗姿,研究了抛秧稻的根系生长特点及其对水稻生长的影响。带土直立苗、带土倾斜苗抛秧活棵立苗快,在根系长度、根系干质量、黄根比方面都优于带土平躺苗和无土平躺苗,后者的立苗速度和根系生长极显著线性相关。秧苗活棵立苗后,带土直立苗、带土倾斜苗分蘖发生迅速且成穗率高,后期有着较强的根系活性,各生育时期保持适宜的根冠比,植株的吸氮速率、叶片的叶绿素含量、根系下扎深度都显著高于带土平躺苗和无土平躺苗。带土直立苗、带土倾斜苗活棵立苗快,其根系生长显著优于带土平躺苗和无土平躺苗,并在各生育时期保持较强的生长势。因此,提高带土直立苗比率、减少平躺苗比率和通过促进根系生长来促进抛秧立苗,进而促进抛秧稻高产、超高产。     

不同淹涝胁迫强度对杂交稻和常规稻农艺性状和生化特性的影响

在分蘖期对目前湖南省普遍栽培的16个杂交稻和常规稻品种进行不同淹涝强度处理,测定了淹涝胁迫处理对杂交稻和常规稻的农艺性状、相对电导率、丙二醛和脯氨酸含量的影响。结果表明： 1）叶片相对受害率的高低表明杂交稻的耐淹涝能力明显强于常规稻。2）随着淹涝天数的增加,杂交稻和常规稻的株高都呈现出低 高 低变化规律,杂交稻出现最高株高的天数在处理4 d后,常规稻在处理2 d后。 3）随着淹涝天数的增加,杂交稻和常规稻的始穗期推迟的天数都增加,杂交稻始穗期推迟的天数幅度小于常规稻。 4）随着淹涝天数的增加,有效穗、实粒数、千粒重、单株产量都降低,杂交稻下降的幅度小于常规稻。 5）随着淹涝天数的增加,杂交稻相对电导率上升的幅度小于常规稻;在杂交稻中,丙二醛含量逐步上升,常规稻表现为先升高后急剧降低的变化趋势;杂交稻脯氨酸含量上升的趋势大于常规稻。 杂交稻耐淹涝胁迫的能力强于常规稻。     

淹水对褐飞虱生长发育和稻株营养成分的影响

 研究了淹水对褐飞虱种群的直接影响,以及淹水导致的稻株营养成分变化和褐飞虱生长发育的关系。结果表明,淹水使褐飞虱的卵的孵化率明显下降,尤其是淹水和高温的互作可杀死稻株内绝大部分褐飞虱卵。淹水能使褐飞虱的取食量、产卵量和生存率都明显下降。同时,淹水使稻株内游离氨基酸含量明显下降,而总糖含量明显增加,从而对褐飞虱的生长发育产生不利影响     

Development of New Submergence Tolerant Rice Variety for Bangladesh Using Marker-Assisted Backcrossing

Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines(BRLs) was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Sub1-line under control ed submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.     

不同育秧方式对水稻秧苗素质及产量性状的影响

以岗优188和南粳9108为材料,研究了泥质法露天育秧、营养土露天育秧和营养土工厂育秧3种育秧方式对秧苗素质及产量性状的影响。结果表明,不同育秧方式对供试品种的大田生育期并无明显影响;泥质法露天育秧所育秧苗茎基宽最高,但秧苗叶面积最小,营养土工厂育秧所育秧苗的地上部鲜质量和干质量明显高于泥质法露天育秧;泥质法露天育秧所育秧苗根数最多,但根鲜质量和根干质量以营养土露天育秧最高;产量方面,2个供试品种均以泥质法露天育秧最高,其次是营养土露天育秧,营养土工厂育秧最低,泥质法露天育秧产量较高的原因在于其每穗总粒数和结实率较高。     

育秧基质与秧盘组合对北方机插稻秧苗素质及产量的影响

在辽宁西部早春温室大棚条件下,以北方粳型超级稻辽粳399为参试品种,探讨了不同育秧基质与秧盘组合处理对机插稻秧苗素质及产量的影响。结果表明,与采用客土作育秧基质相比,其他3种育秧基质均具有提升秧苗素质的作用;与对照(客土+盒式秧盘)相比,其他7个组合处理下的秧苗素质更好,且运输更加方便,移栽根系损伤轻、缓苗时间短,并以M2K2组合处理(有机育苗基质+钵形毯状秧盘)表现最优,产量也最高,比对照增产11.91%。     

杂交水稻苗期发根性状与生育后期根系活力及穗部性状的关系

采用沙培方法,对10个杂交稻组合苗期发根性状与生育后期根系SOD活性、TTC还原力及穗部性状的关系进行了研究。结果表明:苗期发根数、发根鲜重和发根力与孕穗期根系TTC还原力呈极显著正相关,与结实率呈显著或极显著正相关;发根数还与乳熟期SOD活性极显著正相关,与齐穗期TTC还原力显著负相关;发根鲜重和发根干重分别与大部分穗部性状密切相关。回归分析表明,用“发根数×平均发根长”表示发根力能全面地评价杂交水稻苗期发根性状。     

Assessment of Variation in Morpho-Physiological Traits and Genetic Diversity in Relation to Submergence Tolerance of Five Indigenous Lowland Rice Landraces

The present study evaluated submergence responses in 88 lowland indigenous rice(Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in survival rate, shoot elongation, relative growth index, dry matter, chlorophyll, soluble sugar and starch contents were evaluated in two consecutive years under well-drained and completely submerged conditions. Principal component analysis showed that the first three axes contributed 96.820% of the total variation among the landraces, indicating wide variation between genotypes. Major traits such as survival rate, relative growth index, soluble sugar and starch contents appeared to be important determinants of phenotypic diversity among the landraces. Phenotypic coefficient of variance was higher than genotypic coefficient of variance for all the traits and all showed high heritability(90.38%–99.54%). Five rice landraces(Samudrabali, Basnamundi, Gadaba, Surudaka and Dokarakuji) were the most tolerant to submergence. When submerged for up to 14 d, Samudrabali, Basnamundi and Godoba were notable for having greater survival rates than a standard submergence tolerant variety FR13 A, and also notable for elongating more vigorously and accumulating more biomass. These three landraces may therefore be especially useful in lowland rice growing areas that are affected by both moderate stagnant water and flash flooding. Molecular genotyping revealed that the submergence tolerance of Samudrabali, Basnamundi and Godoba is linked to the presence of one or more different Sub1 loci and it may well prove useful for breeding improved submergence tolerant rice varieties, thereby assising to improve yield stability in the rainfed lowland agro-ecosystem.     

沸石基质对水稻秧苗素质的影响

试验以辽粳101为材料,对沸石、珍珠岩、蛭石、营养土四种育秧基质对水稻机插秧苗素质的影响进行了比较研究。结果表明：沸石基质培育的秧苗叶龄、株高适宜,叶绿素含量高,不定根数多,最长根长大,地上干重和根干重大,符合机插秧对秧苗的要求,沸石基质是理想的育秧基质。     

剪根处理对不同秧龄杂交稻幼苗生长及生理特性的影响

以超级杂交稻F优498为材料,采用旱育秧方式育苗,设置不同秧龄(25d和40d)和幼苗伤根处理(整株根系剪去1/3、2/3、全部,以不剪根为对照),进行水培试验,研究根系损伤后(0~48h和1~29d)的生理响应、物质积累、根系形态及氮素吸收特性。结果表明,剪根后不同秧龄秧苗受影响的程度及反应速度不同,秧苗地上部脯氨酸和可溶性糖含量均出现了明显峰值,伤根程度越大,峰值越高,到达峰值的时间越早;25d秧龄的幼苗在剪根后的生理抗性及恢复能力均明显强于40d秧龄的幼苗。从剪根程度来看,不同秧龄下,剪根1/3处理对幼苗生长有一定促进作用,25d秧龄,剪根1/3处理在处理后22d,根系长度、根系表面积、地上部、根系干质量以及根冠比均大于对照,同时该处理氮素积累显著高于对照;40d秧龄,整个生育期根系表面积均随剪根程度的增大而减小,剪根1/3处理在处理后22d,根冠比显著大于对照,处理后29d,地上部、根系干质量、根系长度、氮素积累量以及含氮率均大于对照,而伤根程度较大不仅会导致水稻幼苗根系生长受阻,同时会严重抑制根系对养分的吸收,从而影响水稻幼苗的生长发育。     

水稻育秧环境对秧苗生长的影响

 以汕优63为材料,研究了不同育秧环境下秧苗生理和形态结构方面的差异及对本田生长的影响。旱育秧苗植株矮壮,体内积累的淀粉多,过氧化氢酶活性强,叶绿素含量高,抛植大田后发根快、分蘖多,具有明显的“爆发”优势,最终成穗率高,有效穗多,产量较高;湿润育秧的秧苗,秧田期生长量大,体内积累的淀粉少,抛植大田后发苗慢,缓苗期长,最终有效穗少,产量较低;前期旱育后期多雨寡照的秧苗体内积累的淀粉量及过氧化氢酶活性等均不及正常旱育秧,抛植大田后秧苗体的“爆发”优势丧失,产量与湿润育秧相仿。     

淹水对杂交水稻分蘖期生理生化特性的影响

以威优４８和威优４６为试验材料，研究指出，杂交水稻在分蘖期淹水５０％４ｄ后，叶片的光合速率、叶绿素含量、总糖含量下降，而总氮含量、ＭＤＡ含量和相对电导率上升。碳水合物的减少和脂质过氧化物的积累及膜透性的增加是受涝杂交稻减产的重要原因之一。     

淹涝胁迫对杂交中稻生长特性及产量形成的影响

以近年审定的20个杂交中稻品种为材料,研究了分蘖期和抽穗期淹涝胁迫对杂交中稻的某些生理指标、生长发育、产量及干物质生产的影响。结果表明:(1)淹没胁迫对杂交中稻的生育期有显著影响。分蘖期受淹没胁迫,头季稻和再生稻的抽穗期分别平均延长了3.25 d和3.95 d,成熟期分别平均延长了1.85 d和2.75 d;而抽穗期受淹没胁迫,成熟期会提前,平均提前1.60 d,且品种间差异较大。(2)淹没胁迫对杂交中稻的产量有显著影响。与对照相比,分蘖期受淹没胁迫,分蘖期叶干重、有效穗数、每穗粒数降低,使其平均减产59.0%;齐穗期受淹没胁迫,每穗粒数和结实率显著降低,使其平均减产57.6%。(3)分蘖期受淹没48 h后,不宜割苗蓄留再生稻,应以加强田间管理保留头季稻为主,耐淹性较强的品种有川谷优6684、冈优169和乐优198;抽穗期受淹没48 h后,则以割苗蓄留再生稻较佳,其中冈优169、内5优317、蓉优22和川谷优6684的产量较高。(4)分蘖期和抽穗期耐淹组合间没有相关性,生产上应分别在各时期筛选相应耐淹能力较强的品种。     

不同生育时期淹水对水稻Sub1A耐淹基因导入系产量的影响

在苗期、分蘖期和抽穗期等3个生育时期对常规籼型水稻IR64和IR64 Sub1A耐淹基因导入系(IRRI149)进行淹水处理,测定各个生育时期淹水后的有效分蘖数、每穗粒数、结实率、千粒重和单株产量,以确定不同生育时期淹水对Sub1A耐淹基因导入系产量的影响。结果表明,在苗期淹水,IRRI149和IR64的单株产量分别为39.11 g、24.92 g;分蘖期淹水,分别为10.31 g、0.48 g;抽穗期淹水,分别为24.35 g、23.36 g。IRRI149在苗期和分蘖期淹水条件下,有效分蘖数、每穗粒数、结实率、千粒重、单株产量均显著高于IR64;3个处理时期中以分蘖期淹水对产量的影响最为明显。