不同苜蓿品种种子发芽对盐胁迫的响应

Responses of Seed Germination of Different Alfalfa Varieties to Salt Stress

[目的]针对内蒙古西部地区草地土壤盐碱化,选择盐碱土壤的主要成分NaCl和Na_2SO_4配成混合盐溶液进行室内发芽试验,筛选适合当地种植的耐盐苜蓿品种,为内蒙古西部盐碱草场的苜蓿种植提供理论依据。[方法]将NaCl和Na_2SO_4按摩尔浓度1∶1,用蒸馏水配成含盐量0.0%,0.2%,0.4%,0.6%,0.8%,1.0%,1.2%,1.4%,1.6%,1.8%,2.0%共11个梯度盐溶液,对25个苜蓿品种进行发芽试验,测定种子发芽率、相对发芽指数、种子相对简易活力指数,进行耐盐类型的划分。[结果]轻度盐分胁迫(0.2%和0.4%盐浓度)促进了苜蓿种子发芽,提高了种子的发芽率、相对发芽指数、种子相对简易活力指数;不同苜蓿品种间种子发芽的适宜盐浓度、半致死浓度、极限浓度差异较大。多数苜蓿品种的种子发芽适宜盐浓度是0.0%~0.6%,半致死盐浓度为0.8%,中草3号高达1.4%;极限盐浓度在1.0%~2.0%。[结论]综合聚类分析和种子发芽指标的表现得出,中草3号、新苜2号品种表现出较强的耐盐性,属于耐盐品种,magnumV-wet、赤草1号耐盐性较差。

[Objective] Considering the serious salinity grassland in western Inner Mongolia, we chose two main compositions of the saline soil, NaCl and Na2SO4, mixed in 1： 1 molarity salt solution, to test alfalfa germination characteristics and to choose salt-tolerant alfalfa varieties that were suitable for local production. This work was expected to provide theoretical basis for alfalfa production of Western Inner Mongolia saline meadows. [Methods] A series of mixed salt solution with 11 concentrations of 0.0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0% were used to test salt tolerant traits with regard to seed germination of 25 alfalfa varieties. Of which, germination rate, relative germination index and relatively simple seed vigor index were examined to rank salt-tolerant relevant varieties. [Results] Slight salt stress （0.2 % and 0.4% salt concentrations） was observed that can promoted the alfalfa seed germination. Under the two concentrations, seed germination rate, relative germination index and relatively simple seed vigor index were all increased. Obvious differences of appropriate salt concentration, half lethal salt concentration and lethal salt concentration among different alfalfa varieties existed. For most varieties, their appropriate salt concentration was 0.0%-0.6%, and half lethal salt concentration was 0.8%. Zhongcao No. 3 was an exception, its half lethal salt concentration reached 1.4%. Upper limit of salt concentrations varied between 1.0% and 2.0% mostly. [Conclusion] Considering both results of clustering method and germination index performance, we can concluded that Zhongcao No. 3 and Xinmu No. 2 alfalfa varieties showed better salt tolerance and belonged to tolerant varieties. On the contrary, magnumV-wet, Chimu No. 1 presented worse salt tolerance and belonged to salt sensitive varieties.