干旱程度及时期对复水后大豆生长和代谢补偿效应的影响

为探讨大豆干旱胁迫及复水生长补偿效应和代谢补偿效应机制,建立最佳节水灌溉模式,采用盆栽称质量控水法,研究了干旱胁迫及复水对大豆生长发育、渗透调节、内源激素调节和抗氧化系统的影响。结果表明:干旱胁迫抑制株高和叶面积增长,在苗期和开花期复水天数为0时降幅分别达12.50%~39.74%、21.71%~52.87%和16.93%~36.27%、27.99%~47.80%;导致脯氨酸含量、可溶性糖含量和丙二醛含量升高,在苗期和开花期复水后天数为0的增幅分别达46.97%~131.57%、99.56%~139.37%、6.64%~22.82%和31.68%~136.30%、32.63%~184.51%、15.82%~100.75%;超氧化物歧化酶活性升高,但重度胁迫10 d处理呈降低趋势;脱落酸含量升高,赤霉素和玉米素核苷含量降低,而吲哚乙酸含量苗期呈降低趋势,开花期呈升高趋势。复水后,株高和叶面积日增长量表现出短暂快速增长,产生生长超补偿效应;中度胁迫和胁迫5 d处理各代谢指标产生等量或近等量代谢补偿效应,而重度胁迫和胁迫10 d处理产生近等量或部分代谢补偿效应。因此,干旱胁迫后复水产生补偿效应是有条件的,重度胁迫尤其是长时间重度胁迫会降低补偿效应甚至产生伤害效应。同时苗期适度干旱处理可提高开花期再次受旱的适应能力和补偿效应。

Effects of drought stresses and times on compensation effect after re-watering in soybean

Abstract: As a kind of abiotic stress, drought stress is a common phenomena existing in the plant growth environment. Although drought could cause negative effects such as plant damaged, it also have a positive compensation effect or super compensation effect on physiological and biochemical metabolism during plant growth and development in a short re-watering period after certain drought stress condition, which could make up the loss or damage. Compensation effect, as an important self-regulation mechanism during plant defense responses or resistant to damage, was widely existed in plants and became an important physiological basis for available water regulation and water-saving high-efficiency agriculture realization. At present, drought is the universal phenomenon in spring, of which it in summer and spring-summer has been common and occurred more frequently and the degree was aggravated in recent years in our country. Therefore, in order to explore the metabolic of growth compensation effect and metabolic compensation effect on soybean drought stress and re-watering and establish the best water-saving irrigation mode, we analyzed the effect of drought stress and re-watering on growth, osmotic regulation, endogenous hormone regulation and anti-oxidation system during different stress periods, stress levels and processing times by weighing control the water content, with Sui Nong 14 as experimental material. The results showed that, plant height and leaf area of soybean were inhibited by drought stress, and the decreasing range was 12.50%-39.74%, 21.71%-52.87% and 16.93%-36.27%, 27.99%-47.80% in seeding stage and flowering stage at 0 d re-watering, respectively. The content of praline, soluble sugar and MDA were increased by 46.97%-131.57%, 99.56%-139.37%, 6.64%-22.82% and 31.68%-136.30%, 32.63%-184.51%, 15.82%-100.75% in seeding stage and flowering stage at 0 d re-watering, respectively. The activity of SOD was increased with a decreasing tendency under 10d severe drought stress. The content of ABA was increased, with GA and ZR decreasing, IAA decreased in seedling stage and increased in flowering period. After re-watering, the daily increasing of plant height and leaf area showed a rapid growth in short-term with the over growth compensation effect, metabolic indices in moderate drought stress and 5 d drought stress treatments returned to control levels with a equal or approximately equal metabolic compensation effect; of which these in serious drought stress and 10 d drought stress treatments were showed an approximately equal or partial metabolic compensation effect. This implied that the occurrence of compensation effect under drought stress after re-watering was conditional. The severe drought stress or long time drought stress could decreased the compensation effect and damaged the plant at last, while the appropriate drought treatments in seedling period could improve drought adaptability and compensation effect under once again the drought stress in flowering. Therefore, a moderate drought resistance exercise should be carried out in seedling stage in order to improve the adaptability with drought environment in the late growing, but not suitable for severe drought stress especially for long time. A best water-saving irrigation mode should be established by reasonable utilization of plant drought compensation effect mechanism so that it could be provide a theoretical for the analysis of compensation effect mechanism and cultivation techniques of drought resistance and high yield on soybean.