硒对不同品种紫花苜蓿发芽阶段物质转化和形态建成的影响

Effects of selenium on metabolic transformation and morphogenesis in different varieties of alfalfa during the germination stage

为了探究外源硒对不同品种紫花苜蓿种子萌发阶段糖、氮物质转化,发芽指标和形态建成的影响,以甘农3号、DS310FY及中苜5号紫花苜蓿为对象,设置5个亚硒酸钠浓度(0、0.3、0.6、1.2、2.4 mg·L^(-1)),培养10 d后测定苜蓿种子的发芽率,表型及生理指标和硒含量,并运用综合分析和相关性分析探究各生理指标与表型的关系,以筛选出最适宜的硒浓度和潜在的硒营养强化材料。结果表明:施硒处理4 d,DS310FY和甘农3号苜蓿幼苗的还原糖含量、可溶性糖含量及发芽势均在0.6 mg·L^(-1)硒处理下显著高于对照(P<0.05);施硒处理10 d,0.3、0.6 mg·L^(-1)硒处理下DS310FY和甘农3号苜蓿幼苗的还原糖含量、硝酸还原酶活性、发芽率及发芽指数都显著高于对照(P<0.05);而甘农3号苜蓿幼苗的胚芽长及DS310FY苜蓿幼苗的总氨基酸含量、活力指数、胚芽长、胚根长及单株鲜重,施硒后的最大值相比对照均显著提高(P<0.05);另外,0.3 mg·L^(-1)硒处理下相比对照也显著提高了中苜5号苜蓿幼苗的蔗糖含量、发芽率及胚根直径(P<0.05)。相关性分析和各指标的变化趋势表明,苜蓿幼苗糖的积累和转化主要促进胚根的发育,而氮的积累和转化主要促进胚芽的伸长和单株鲜重的增加。因此,施硒后糖转化效率的提高主要促进苜蓿种子的萌发,而氮转化效率的提高主要促进苜蓿幼苗的形态建成。综上,以0.6 mg·L^(-1)硒处理下DS310FY紫花苜蓿发芽阶段的物质转化和形态建成综合表现最佳,更适宜进行硒的营养强化。

This research explored the effects of exogenous selenium on the metabolic transformations of sugar and nitrogen,germination indicators and morphogenesis in seeds of different varieties of alfalfa(Medicago sativa)during the germination stage.Five sodium selenite concentrations(0,0.3,0.6,1.2,2.4 mg·L^(-1))were applied to M.sativa cv.Gannong No.3,DS310FY and M.sativa cv.Zhongmu No.5 seeds.The germination rate,phenotype,physiological indicators and selenium content of the treated seeds were determined after 10 days of culture,and multivariate and correlation analyses were used to explore the relationship between various physiological indicators and the phenotypic traits,so as to identify the most suitable selenium concentration and potentially define a methodology for producing selenium fortified materials.It was found that the reducing sugar content,soluble sugar content and germination potential of DS310FY and M.sativa cv.Gannong No.3 seedlings were all significantly higher than those of the control under 0.6 mg·L^(-1)selenium treatment for 4 d(P<0.05).The reducing sugar content,nitrate reductase activity,germination rate and germination index of DS310FY and M.sativa cv.Gannong No.3 seedlings were all significantly higher than those of the control under 0.3 and 0.6 mg·L^(-1)selenium treatment for 10 d(P<0.05),while the maximum values of epicotyl length of M.sativa cv.Gannong No.3 seedlings and total amino acid content,vigor index,epicotyl length,hypocotyl length,and fresh weight per plant of DS310FY alfalfa seedlings were all significantly higher after selenium application than in the control(P<0.05).In addition,0.3 mg·L^(-1)selenium treatment also significantly increased sucrose content,germination rate and hypocotyl diameter of M.sativa Zhongmu No.5 seedlings compared to the control(P<0.05).Correlation analysis and variation trend of each indicator showed that the accumulation and transformation of sugar in alfalfa seedlings mainly promoted the development of the hypocotyl,while the accumulation and transformation of nitrogen mainly promoted the elongation of the epicotyl and the increase in plant fresh weight.Therefore,increased sugar conversion efficiency after selenium application mainly promoted the germination of alfalfa seeds,while increased nitrogen conversion efficiency mainly promoted the morphological establishment of the seedlings.In conclusion,the overall performance of metabolic transformation and morphogenesis of DS310FY alfalfa during germination was best under 0.6 mg·L^(-1)selenium treatment and this treatment also provided selenium nutrient fortification.