普通菜豆抗旱生理特性

采用盆栽试验,以抗旱性较好的品种跃进豆、260205和敏感品种奶花芸豆为试材,设置干旱和正常供水2种处理,测定产量、产量构成因素及相关生理生化指标,分析干旱胁迫下参试品种各性状及生理指标的变化及对干旱胁迫的生理响应。结果表明,干旱处理36 d,跃进豆和260205的根干重为总生物量的20.2%和20.6%,荚干重为总生物量的30.0%和28.9%,而奶花芸豆的根干重和荚干重仅为总生物量的10.6%和17.1%,光合产物向根系和籽粒的有效分配与普通菜豆抗旱性关系密切;跃进豆在干旱胁迫后期的水分利用效率较对照增加230.5%,而奶花芸豆的增幅仅为84.3%,较高的水分利用效率有利于CO2的有效扩散和高效固定;其他生理特性分析表明,抗氧化酶与光呼吸共同作用有效降低了膜脂过氧化程度,减少了叶片的损伤;脯氨酸和可溶性糖是普通菜豆主要的渗透调节物质,能够较好地保持自身叶片的水分平衡。普通菜豆抗旱性是多种生理调节机制协同作用的结果,主要包括形态调节、气孔调节、渗透调节以及抗氧化能力的调节等。

Physiological Characteristics of Drought Resistance in Common Bean (Phaseolus vulgaris L.)

hree common bean cultivars, Yuejindou (drought-resistant), 260205 (drought-resistant) and Naihuayundou (drought-susceptible) were evaluated with two treatments (drought stress and normal water supply) in pot experiments. We determined physiological and biochemical parameters during growth stage and yield and traits related to yield after harvest, analyzed the changes of all parameters and indicators under drought stress. The result showed that the root dry weight of Yuejindou and 260205 was 20.2% and 20.6% of the total biomass and the pod dry weight was 30.0% and 28.9% of the total biomass especially at 36 days of drought treatment, while, the root dry weight and pod dry weight only 10.6% and 17.1% of the total biomass in Naihuayundou, indicating that effective photosynthate distribution is significantly correlated with drought resistance in common bean.The water use efficiency in the drought-resistant cultivar (Yuejindou) increased by 230.5% compared with control, much higher than the 60% increase in drought-susceptible cultivar (Naihuayundou). The drought-resistant cultivars had an efficient CO₂ diffusion and fixation in leaf tissues, and an effective water-use. In drought-resistant cultivars, antioxidant enzyme and photorespiration played a significant role in reactive oxygen scavenging; proline and soluble sugar contributed to the maintenance of relative water content in leaves under low water potential. All together, our results indicated that the competence of drought-resistant cultivars to maintain seed production under drought stress relies on effective adjustments in morphology, stomatal conductance, osmosis and antioxidant capacity.