【作者】 胡颂平；

【导师】 周清明；

【作者基本信息】 湖南农业大学 ， 作物育种， 2002， 博士

【摘要】 为了探明巴西陆稻IAPAR9的抗旱特性，本文以抗旱性强的品种Moroberekan、Azucena，抗旱性弱的品种Maratelli、Sariceltik以及抗旱性中等的品种IRAT104，另选用两系杂交组合八两优96和常规水稻湘早籼24号为材料，运用旱棚盆栽与大田试验相结合的方法，从形态解剖、生理、生化及激素四方面对其进行了深入系统的研究。首次较全面的揭示了IAPAR9抗旱的本质，为进一步利用陆稻抗旱资源和发展陆稻生产打下了一定理论基础，主要结论如下： 1、形态解剖结果表明： (1)稻的根长、根体积、根重均与稻品种抗旱性呈极显著正相关(r分别为：0.8607、0.7381、0.7149)，IAPAR9具有中等发达程度的根系；干旱使稻品种根系内导管面积及数量大幅降低，但严重干旱(40％田间持水量)及干旱处理达100天时，IAPAR9仍能维持一定生长量，这是IAPAR9抗旱性较好的物质基础之一。另外，研究发现不同抗旱性的稻品种根内导管数目明显不同，如在苗期湘早籼24号根内导管数为3，八两优96为4，IAPAR9为7，IRAT104为8。 (2)地上部重量、株高、叶面积亦与稻品种抗旱性呈极显著或显著正相关(r分别为：0.7393、0.8091、0.6550)，茎蘖数量则与稻品种抗旱性呈负相关(r=-0.6732)。IAPAR9地上部组织含水量较一般品种大，显示该品种具有较强的保水力。 (3)叶片气孔密度与抗旱性关系不明显(r=0.1015)，但随土壤含水量降低而大幅降低，气孔面积也相应减小，同时叶内所含维管束数量及束内导管面积、气腔数量和面积均大幅降低。干旱对角质层厚度影响不大；IAPAR9在干旱严重时，仍能维持较发达的输导和通气组织，这是IAPAR9抗旱性较好的又一物质结构基础。 2、相关生理研究表明 (1)严重干旱时稻品种光合速率大小与其抗旱性呈显著正相关(r=0.6216)，IAPAR9在干旱时具有较高的光合速率；干旱能使稻叶片叶绿素总量小幅度降低，气孔阻力则变化复杂，总体上表现随干旱加重而增大；IAPAR9具有较低的气孔阻力。 (2)干旱使稻品种可溶性糖含量增加，蛋白质含量变化较小，脯氨酸大量增加，但三 湖南农业人学地十论文 一 者均与稻品种抗旱性相关不显著）分别为：心．4463、o．5007、心．4020）IAPARg具中等 水平的可溶性糖，蛋白质及脯氨酸含量。 ＊）蒸腾速率在田间持水量的60％到80％时随土壤含水量降低而下降，低于60％m 间持水量时，各品种表现不一；水分利用效率随干旱情况不同变化复杂，1＊卜ARg具有S 较高的水分利用效率。 （水势值与稻8；种抗旱性大小呈极显著下相关）刃．7328””），它随干旱程度变化明 显，而随干旱处理时间变化不明显。1＊PA＊9具较高的组织水势值。茎叶组织含水量高 低亦能反映品种抗旱性大小（－0石867、，IAPARg具较高的茎叶含水量；稻品种根系活 力与其抗旱性大小呈显著负相关汀—0石782”），但与产量相关极显著仁－0．7382””）。 ＊干旱使各品种产量及相关构成因子均降低。IAPARg比一般陆稻具更强的分巍能 力。不同水分等级的抗旱系数大小不一致，以80％m间持水量的抗旱系数较能反映品种 的实际抗旱能力。 3、有关生化研究结果表明 ＊）相关酶活性以SOD、POD、NM酶活性变化较能反映稻品种的抗旱性，其变幅 大小可作为稻品种抗旱性评价的良好生化指标；CAT酶活性则变化复杂，不宜作稻品 种抗旱性指标。IAPARg具较高的POD酶活性水平，中等SOD、NRA、CAT酶活性水 平。 （2首次发现稻品种NRA酶活性变幅与抗旱性相关密切汀—0．8615”），而且NRA酶 活性与土壤含水量呈极显著正相关）－0．94广卜 山此推断可以用稻叶片 NRA酶活性指 示土壤含水量及作稻灌溉指标。 ＊）干旱对MDA含量变化的影响，各．n冲I’表现不一，们其含显与揪a．种抗早性显著 负相关 Y乙0石944”卜 因此亦能反映稻品种抗旱性；吸透性变幅大小也能反映稻品种的 抗早性汀乙0石sl6‘），但稻．p用休身腆透竹大小并不能反映其抗早性人小，囚为有些抗早 性强的另．种且有较大的膜透性，但在干旱时较稳定，吸透性变幅小；IAPARg具较大的 膜透性。 4、激素研究表明 干旱时，稻品种ABA、IAA、Z含量变化较为复杂，总体上有ABA含量上升而IAA、 ”Z含量降低的趋势，IAPARg具较高的 ABA、较低的 IAA、中等的 Z含量水平。更多还原

【Abstract】 The character of drought resistance of Brazilian upland rice-IAPAR9 was studied deeply and systematicly with comparison of some rice varieties-Moroberekan,Azucena Maratelli,Sariceltik,Biliang you 96 and Xiang zao xian 24,by the methods of pot and field culture. This research exposed firstly and totally the mechanism of drought resistance in Brazilian upland rice-IAPAR9 and provided a good theoretical basis for utilizing resource of drought resistant germplasm in upland rice and developing product of upland rice. The main results were as follows:1,The results of morphology and anatomy showed that:(1) The correlation between drought resistant ability of rice and its length,volume weight were significant (r was 0.8607,0.7381,0.7149 respectively);IAPAR9 had a middle level of roots;Both number and area of conduct in roots of rice were decreased greatly under drought stress,but IAPAR9 could maintain larger growth than others while drought was serious (40% soil saturated water content )and treated time reached 100 days,this should be one of matter bases on which it had a good drought resistant ability. Meanwhile,we found that numbers of roots conduct of rice varieties were different,for example,number of roots conduct in Xiang zhaoxian24,BaLiang you96,IAPAR9 and IRAT104 were 3,4,7,8 respectively while they were in seedling stage.(2) The correlation between drought resistant ability of rice and it’s weight of stems and leaves,plant height,leaf area were also significant (r was 0.7393,0.809r,0.6550 respectively),but it was correlative negatively(r=-0.6732) between number of stems and tillers and its drought resistant ability. The result appeared that 1APAR9 had a stronger maintaining water ability because its water content of stems and leaves was more than that of general varieties.(3) Leaf stomatal density of rice varieties was not correlative to its drought resistant ability (r=0.1015),but it would be decreased greatly with the cut of soil water content (-26 --44%) and stomatal area was also cut down. Both number of vascular bundles,air cavities andconduct area of vascular bundles,area of air cavities in leaves were greatly cut down,but thickness of waxen film would not be affected;IAPAR9 could maintain stronger conduct and aired tissue while it encountered drought stress,This was its another matter base of good drought resistance. 2 The results from physiologic studies showed that:(1) The correlation between photosynthetic rate of rice varieties and its drought resistant ability in the serious drought stress was significant (r=0.6216). IAPAR9 had higher photosynthetic rate under drought stress;Meanwhile,total chlorophyll content of rice leaves would be cut down smoothly in drought stress,and conditions of stomatal resistance was very complicated,but it would be increased in totally;IAPAR9 had a low level of stomatal resistance.(2) Soluble sugar of rice varieties would be in creased,and protein content varied little in drought stress but free proline would increase greatly,and the correlation were not significant between them and drought resistant ability of rice varieties (r was -0.4463,-0.5007,-0.4000 respectively). IAPAR9 had middle level of soluble sugar protein and proline.(3)Transpiration rate would cut down with decreasing of soil water content when soil water content was 60%-80% soil saturated water content,once under 60% soil saturated water content,each variety would have different appearance;Meanwhile,Water use efficiency was varied complexly under drought stress,and IAPAR9 had higher WUE.(4)The correlation between leaf water potential and drought resistant ability of rice varieties was significant (r=0.7328).It varied apparently to levels of drought,and varied not apparently to time of drought;IAPAR9 had a higher tissue water potential;Moreover,water content of stems and leaves could indicate drought resistant ability of varieties too(r=0.6867);IAPAR9 had higher water content of stems and leaves;but the correlation between roots vigor and drought resistant ability was negative (r=-更多还原