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为明确盐害、干旱及盐旱复合胁迫对小麦幼苗生长和水分吸收的影响,从而为盐害和干旱胁迫下栽培调控提供理论依据。以2个抗旱性不同的小麦品种(扬麦16和耐旱型洛旱7号)为材料,采用水培试验,以NaCl和PEG模拟盐旱复合胁迫,研究了盐旱复合胁迫下小麦幼苗生长、根系形态、光合特性及水分吸收特性的变化。结果表明,盐、旱及复合胁迫下小麦幼苗的生物量、叶面积、总根长与根系表面积、叶绿素荧光和净光合速率均显著下降,但是复合胁迫处理的降幅却显著低于单一胁迫。盐旱复合胁迫下根系水导速率和根系伤流液强度显著大于单一胁迫,从而提高了小麦幼苗叶片水势和相对含水量。盐胁迫下小麦幼苗Na~+/K~+显著大于复合胁迫,但复合胁迫下ABA含量却显著小于单一的盐害和干旱胁迫。因此,盐旱复合胁迫可以通过增强根系水分吸收及降低根叶中ABA含量以维持较高光合能力,这是盐旱复合胁迫提高小麦适应性的重要原因。洛旱7号和扬麦16对盐及盐旱复合胁迫的响应基本一致,但在干旱胁迫下洛旱7号表现出明显的耐性。
In order to clarify the effects of salt, drought and salt-drought combined stresses on the growth and water absorption of wheat seedlings, a theoretical basis for the regulation of cultivation under salt stress and drought stress was provided. Two wheat cultivars with different drought resistance (Yangmai 16 and drought-tolerant Luohan 7) were used as materials to study the effects of salt and water stress on the seedling growth of wheat under NaCl-PEG stress. , Root morphology, photosynthetic characteristics and water absorption characteristics. The results showed that the biomass, leaf area, total root length, root surface area, chlorophyll fluorescence and net photosynthetic rate of wheat seedlings decreased significantly under salt, drought and combined stress, but decreased significantly under single stress. Under salt-drought combined stress, the root conductance rate and root trauma intensity were significantly higher than single stress, which increased the water potential and relative water content of wheat seedling leaves. Under salt stress, the Na ~ + / K ~ + content of wheat seedlings was significantly greater than that of combined stress, but the ABA content under combined stress was significantly lower than that of single salt stress and drought stress. Therefore, salt-drought combined stress can maintain higher photosynthetic capacity by enhancing water absorption of roots and reducing ABA content in root and shoot, which is an important reason for improving adaptability of wheat by salt-drought combined stress. Luohan 7 and Yangmai 16 were basically the same in response to salt and salt-drought stress, but Luohan 7 showed obvious tolerance under drought stress.