披碱草属野生种质资源苗期耐盐性评价及相关生理机制研究

Evaluation of Salt-tolerance and the Related Physiological Characteristics of Wild Elymus spp.

【目的】对披碱草属野生种质资源进行苗期耐盐性评价,并对其生理机制进行初步研究,用以发掘和利用具有优良耐盐性状的披碱草野生种质资源,并为利用生理生化指标进行苗期快速准确鉴定提供依据。【方法】设置对照(0)、0.4%、0.6%、0.8%和1.0%等5个土壤盐浓度水平,对披碱草属20份野生种质材料的苗期生长参数进行测定,在此基础上采用极差分类进行种质材料的耐盐性排序。测定不同盐浓度胁迫下的游离脯氨酸含量和细胞膜透性,以及抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)的活性的变化。【结果】随着盐浓度的增加,各供试材料的株高、分蘖、存活率及植株干重均呈现下降趋势,但不同材料对盐胁迫的响应有较大差异。随着盐浓度的升高,参试材料叶组织中游离脯氨酸含量呈上升趋势,在0.8%和1.0%盐浓度胁迫下,耐盐材料G5和G13的相对游离脯氨酸含量显著高于其它材料(P<0.05);而相对细胞膜透性显著低于其它材料(P<0.05);APX和SOD酶的活性也随着盐浓度的升高而升高,在0.8%和1.0%盐浓度胁迫下,耐盐材料G5、G13叶组织中APX和SOD的活性显著高于其它材料(P<0.05)。【结论】20份野生披碱草种质材料在耐盐性上存在较大差异,耐盐性强的披碱草可作为耐盐性种质资源加以利用。植株苗期的游离脯氨酸、细胞膜透性、APX酶和SOD酶活性对盐胁迫浓度的变化响应灵敏,且在耐盐性不同的材料中变化差异显著,可以作为快速鉴定披碱草野生种质材料耐盐性的生理生化指标。

[ Objective ] Salt-tolerance and physiological responses of wildryes （Elymus spp.） collected from natural populations were evaluated under a range of NaCI concentrations to explore and utilize the germplasm with high salt-tolerance and to provide physiological indicators for identifying salt-tolerance at seedling stage. [Method] The growth parameters of 20 accessions of Elymus spp. at early seedling stage were measured under various salt stress at 0, 0.4%, 0.6%, 0.8% and 1.0% NaCI in the soil, and the accessions were sorted out using the method of polar ordination. The physiological characteristics of the accessions in terms of concentration of proline, electrolyte leakage percentage, APX and SOD enzyme activities were also analyzed. [Result] It was shown that the plant height, tiller number, survival rate and dry weight decreased with the increase of soil salt concentration, although accessions differ in the degree of response to salt tolerance. Proline content in leaf increased in response to increased salt stress, with accessions G5 and G13 having significantly higher proline content, while lower relative electrolyte leakage percentage, than the others when salt concentration at 0.8% and 1.0% （P〈0.05）. APX and SOD enzyme activities also increased with salt stress, those of G5 and G13 significantly higher than those of the other accessions （P〈0.05）. [Conclusion] Remarkable variations in salt tolerance were detected among the 20 wildrye accessions, which have provided a basis for utilization of salt tolerant wildrye genetic resources. It was also evident that the levels of proline, electrolyte leakage percentage, APX and SOD enzyme activities in the leaf at seedling stage responded sensitively to the level of salt stress and thus can be used as physiological indicators for quick and accurate identification of salt tolerant wildrye germplasm.