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研究了三个水稻品种80-85,83-45和83-51分蘖期对盐逆境的生理反应。0.5％NaCl溶液灌溉后,三个品种叶水势(Ψ_w)的下降均可由叶片渗透势(Ψ_π)的下降所抵偿。耐盐品种80-85比另两个品种显示较大的渗透调节能力,其特点是:叶水势下降幅度大,相对含水量(RWC)较高,气孔扩散阻抗值较小。这种适应可使水汽和CO_2的扩散交换处于较佳状态,从而生长受阻较小。 水稻对K~+有选择吸收作用。耐盐品种80-85叶内含Na~+量较少,有较大的K:Na比值。不耐盐品种叶内过量离子积累,特别是Na~+的积累是盐渍下生理伤害的主要原因。未能确定游离脯氨酸含量对渗透调节作用的贡献,也未见脯氨酸的积累与品种耐盐性之间的相关,但可观察到脯氨酸的积累与叶内Na~+增高和生长受阻的伴随现象。从生理上看,品种80-85具有系列适应性状,它对开拓利用盐土资源具有一定的应用价值。
Physiological responses to salt stress at tillering stage of three rice cultivars 80-85, 83-45 and 83-51 were studied. After irrigation with 0.5% NaCl solution, the decrease of leaf water potential (Ψ_w) was offset by the decrease of leaf osmotic potential (Ψ_π). Salt tolerant cultivars 80-85 showed greater osmotic adjustment than the other two cultivars, which were characterized by large drop in leaf water potential, higher relative water content (RWC) and smaller stomatal diffusion resistance. This adaptation allows better exchange of water vapor and diffusion of CO 2, resulting in less resistance to growth. Rice has selective absorption of K ~ +. Salt-tolerant varieties 80-85 leaf Na + content is less, with a larger K: Na ratio. Excessive ion accumulation in leaves of salt-tolerant salt species, especially accumulation of Na ~ +, was the main reason of physiological damage under salt stress. The contribution of free proline content to osmotic adjustment was not ascertained, nor was there any correlation between proline accumulation and salt tolerance of cultivars, but accumulation of proline and increase of Na ~ + in leaves were observed Obstacle to growth accompanied by the phenomenon. Physiologically, the varieties 80-85 have a series of adaptive traits, which have certain application value for exploiting and utilizing the salt and earth resources.