土壤盐胁迫降低后甜高粱的补偿生长和盐离子分布特征

The compensation growth and salt ion distribution in sweet sorghum (Sorghum bicolor L. Moench) after salt stress reduction

  • 摘要: 逆境补偿效应在作物中普遍存在, 对作物生长发育与产量产生重要的影响。为阐明土壤盐度降低后甜高粱的补偿生长效应, 本研究采用盆栽方法, 将甜高粱拔节期的土壤含盐量设置3个梯度: 5 gkg-1(高盐处理)、由5 gkg1降低到2 gkg-1(盐度降低处理)、2 gkg-1(低盐对照), 测定2个甜高粱品种地上部器官(茎秆、叶片、叶鞘)干物质生长速率与积累, 以及盐离子(Na+、Cl-、K+)在不同器官的含量。结果表明: 高盐处理甜高粱地上部干物质增长速率一直显著低于对照; 土壤盐度降低后, 各器官干物质生长速率明显升高, 并超过对照, 产生了超补偿效应。成熟期高盐处理株高与地上部干物质大幅下降; 土壤盐度降低后‘辽甜1号’的株高与地上部干物质较低盐对照分别下降7.69%和33.21%, 而‘中科甜3号’的株高和地上部干物质重与对照没有差异。高盐处理后各器官干物质中Na+和Cl-含量较对照大幅度提高, K+含量增加幅度较小。土壤盐分降低后的35 d, 甜高粱Na+和Cl-在各器官中含量虽仍高于对照, 但比高盐处理已大幅下降; 茎秆与叶鞘K+的含量较对照有小幅提高, 而叶片K+含量与对照无显著差异。本研究表明: 甜高粱盐胁迫降低后离子毒害减轻、生长速率加快直至超过对照, 耐盐甜高粱品种补偿效应尤为明显, 成熟期干物质产量可与对照相当。本研究结果可为盐碱地甜高粱栽培提供理论依据。

     

    Abstract: Adversity compensation effect is ubiquity in crops, which impacts on crop growth, development and yield. To elucidate the compensation growth of sweet sorghum following soil salt stress reduction, a pot experiment was conducted, in which 5 gkg-1 (high salt), 2 gkg-1 down from 5 gkg-1 (salt stress reduction) and 2 gkg-1 (low-salt control) of soil salt treatments were applied at the elongation stage of sweet sorghum. Then growth rate of dry matter on aboveground parts (leaf, leaf sheath and stem) and aboveground dry matter at maturity of two cultivated sweet sorghum varieties were determined. The experiment also measured salt ions (K+, Na+ and Cl-) distribution in aboveground organs of sweet sorghum. The results showed that the growth rate of aboveground dry matter in high salt treatment was always significantly lower than that of control. There was clear acceleration of growth after soil salt reduction, and gradually exceeded the growth of control due to overcompensation effect. At maturity stage, both plant height and aboveground dry matter of two sorghum varieties decreased sharply in high salt treatment. They decreased by 7.69% and 33.21%, respectively, in ‘Liaotian 1’ in salt stress reduction treatment compared with the low-salt control, moreover, no obviously difference was found in both plant height and aboveground dry matter of ‘Zhongketian 3’ between salt stress reduction treatment and low-salt control. The contents of Na+ and Cl- in aboveground organs significantly increased, and K+ content slightly increased under high salt stressed condition. At 35 days after soil salt reduction, the contents of Na+ and Cl- still higher than that of low-salt control, but decreased significantly compared to that of high salt treatment. Although K+ content in both leaf sheath and stem in soil salt reduction treatment were higher than that of low-salt control, no difference was observed in leaf. The results suggested that ion toxicity in salt-stressed sweet sorghum alleviated after soil salt reduction, and the growth rate eventually exceed that of low-salt control due to overcompensation effect, especially, for salt-tolerance cultivar ‘Zhongketian 3’. This provided the theoretical basis for sweet sorghum cultivation in saline-alkali soils.

     

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