东乡野生稻渗入系苗期抗旱遗传及生理机制初步分析

摘要

With the repeated natural drought method and the 20% (w/v) PEG -6000 simulated drought method , the drought resistance of seedlings of a BIL population (BC1F9) of Dongxiang common wild rice (Dwr)/Xieqingzao B(Xqz B)//Xqz B were examined by drought treatment assay and genetic analysis. The control materials included the strong drought - resistant varieties, Brazil upland rice, Dongxiang common wild rice and the drought - sensitive cultivar Xqz B, using grade of drought resistance based on seedling wilting as evaluation indice. The result showed that after two repeated natural droughts and recovering growth in 1/2MS nutrient solution, the mean grades of drought resistance of 230 BC1F9 BIL population were 3. 76 and 4. 39,respectively. The continuous normal distribution of wilting rates suggested that drought resistance at the seedling stage in Dwr indicated the inheritance of qualitative - quantitative traits. The lines with 1 ~ 2 grades of drought resistance under natural drought were further treated with the stress of 20% ( w/v) PEG -6000 simulated drought. The lines 1112, 1168, 1172 and 1315 were of strong drought resistance and can be further used for exploring and utilizing of drought resistance genes. Under 20% ( w/v ) PEG - 6000 simulated drought stress,increases in the soluble sugar, proline content and SOD activity in the strong drought resistance line 1112 were larger than those in the weak drought resistant line 1323. Decreases in GSH content were smaller than in weak drought resistance lines, indicating that penetration materials were accumulated more rapidly and increased more in strong drought resistance lines than in weak drought resistance lines. And the accumulation of membrane peroxidation was slower, better for adaption to drought environment.%以强抗旱性的巴西旱稻、东乡野生稻和弱抗旱性的栽培稻协青早B为对照品种,以基于萎蔫率的抗旱等级为鉴定指标,采用苗期反复自然干旱鉴定法和20％ PEG6000模拟干旱法,对江西东乡普通野生稻(Oryza rufipogon)/协青早B//协青早B构建的回交重组自交系(Backcross inbred lines,BIL)群体(BC1F9)进行茁期抗旱机理及遗传分析.结果表明:230个BC1F9 BIL群体经2次反复自然干旱后,在1/2MS营养液恢复生长的平均抗旱等级分别为3.76和4.39,萎蔫率呈连续正态分布,暗示东乡野生稻苗期抗旱性表现为质量-数量性状遗传性状特征.将干旱处理一次后等级为1级的14个株系,在20％ PEG6000模拟干旱条件下进行处理,结果与反复干旱二次后结果一致,株系1112、1168、1172和1315为强抗旱基因渗入系,可进一步用于抗旱基因的挖掘与利用.在20％ PEG6000模拟干旱条件下,强抗旱性株系1112苗期叶片的可溶性糖、脯氨酸含量和SOD活性增加幅度都大于弱抗旱性株系1323,GSH含量下降幅度则低于弱抗旱株系,说明强抗旱株系渗透物质比弱抗旱株系积累快且幅度大,而细胞膜过氧化产物积累速度较慢,更有利于适应干旱环境.