耐盐性不同水稻品种根系对盐胁迫的响应差异及其机理研究

Different Responses of Roots of Rice Varieties to Salt Stress and the Underlying Mechanisms

为阐明耐盐性不同的水稻品种根系和产量对盐胁迫的响应及其生理特性,以4个耐盐水稻品种和2个盐敏感水稻品种为材料,设置4个不同的盐浓度处理(0.0、1.0、2.0和2.5g/kg)。结果表明,与盐敏感水稻品种相比,耐盐水稻品种能够耐受更高浓度的盐胁迫(2.5g/kg),且减产幅度较小。耐盐水稻品种具有较高的产量,得益于其较高的总颖花量和结实率,且总颖花量对产量的影响最大。与盐敏感水稻品种相比,在分蘖中期、穗分化期和抽穗后15d,耐盐水稻品种在盐胁迫下具有更大的根系总吸收表面积和活跃吸收表面积,更高的根系氧化力,更有优势的根长、根直径和根表面积,较低的过氧化氢含量,较高的脱落酸含量以及更强的固定Na^(+)的能力。上述结果表明,分蘖中期、穗分化期和抽穗后15d根系生理性状和形态性状差异会影响水稻产量构成因素中的总颖花量和结实率,进而影响产量,且根干重与根长对总颖花量和结实率的影响最大。这也证实了较发达的根系是水稻具有较强耐盐性的生理基础。耐盐水稻良好的根系生理和形态性状是获得高产的基础。该研究结果对水稻耐盐生理机制研究与水稻耐盐育种有借鉴意义。

The objective of this study is to elucidate the responses of root traits and yields of salt-tolerant and salt-susceptible rice varieties to different levels of salt stress,four salt-tolerant rice varieties and two salt-susceptible rice varieties with four different salt concentration levels,including 0.0,1.0,2.0 and 2.5g/kg.Results showed that the yields of salt-tolerant varieties were less reduced than that of salt-susceptible varieties,and salt-tolerant varieties were able to tolerate higher salt concentration of 2.5g/kg.Salt-tolerant varieties produced higher grain yield mainly due to the greater total spikelets and higher filled grain percentage,and the number of total spikelets had the greatest effect on grain yield.Salt-tolerant rice varieties had higher total root absorption area and active absorption area,higher root oxidation activity,higher root length,root diameter and root surface area,lower content of H_(2)O_(2),higher content of abscisic acid and stronger ability to retain Na^(+) under salt stress from mid-tillering to heading.The above results showed that the differences of root physiological and morphological traits in mid-tillering stage,panicle stage and 15 days after heading could affect the number of total spikelets and seed-setting rate of rice,and then affect rice yield.Root dry weight and root length had the greatest effects on total spikelets number and seed-setting rate.Results indicated that the developed root system was the physiological basis of salt tolerance of rice.The better root physiological and morphological indexes of salt-tolerant rice varieties were the basis for achieving high yield.The results of this study could be helpful for the physiological researches and the breeding of salt-tolerant rice.