甜高粱对混合盐碱胁迫的响应及耐盐碱种质鉴定

The Response and Screening of Germplasm Tolerant to Mixed Saline-Alkali Stress in Sweet Sorghum

为评价甜高粱资源对混合盐碱胁迫的耐受性,挖掘耐混合盐碱胁迫甜高粱资源,并筛选适合甜高粱芽期和苗期耐混合盐碱胁迫的鉴定指标,本研究设置4个不同浓度混合盐碱液(T1、T2、T3和T4,对应的Na+浓度分别为50、100、200、300mmol/L;对应的p H分别为7.12、8.01、8.80、10.07)对5个甜高粱品种进行胁迫处理,测定了甜高粱的相对发芽率、幼苗茎叶鲜重、叶片相对电导率、叶片脯氨酸含量、叶片过氧化物歧化酶(SOD)活性等指标,采用模糊数学隶属函数法和灰色关联分析法评价各材料耐盐性的强弱。结果显示,随着胁迫强度的增加,所有材料的相对发芽率和茎叶鲜重均呈现下降趋势,相对电导率和脯氨酸含量均呈现上升趋势,而SOD活性则表现出先升高后降低的趋势,在T3处理SOD活性达到最高值。依据T3处理的各项数据进行灰色关联分析,结果显示,5个测定指标与综合抗盐碱指数的关联度大小排序依次为脯氨酸含量(0.95)、茎叶鲜重(0.93)、相对电导率(0.92)、SOD活性(0.91)和相对发芽率(0.74)。5个材料耐盐碱适应能力强弱按隶属函数法的排序为雅津106号>雅津4589号>雅津2号>雅津4184号>雅津10号,按灰色关联分析法的排序为雅津2号>雅津106号>雅津4589号>雅津4184号>雅津10号。以上结果表明,5份甜高粱种质对混合盐碱胁迫的耐受性存在显著差异,茎叶鲜重、脯氨酸含量、相对电导率和SOD活性是评价甜高粱耐盐碱胁迫性的关键指标,雅津106号的抗盐碱能力最强,雅津10号的抗盐碱能力最弱。

Physiological responses of sweet sorghum to mixed saline-alkali stress were evaluated to explore the high saline-alkali tolerance germplasm and provide physiological indicators for identifying saline-alkali tolerance at seedling stage. Two growth characteristics （relative germination rate and fresh weight of per plant） and three physiological characteristics （leaf relative electrical conductivity, proline content and SOD activity） were measured at germination and seedling stages of 5 sweet sorghums under four mixed saline-alkali stress conditions. The saline- alkali tolerance was sorted out using the method of membership function and grey relation method in 5 genotypes. The four stress levels were named as T1, T2, T3 and T4, which Na＋ concentration were 50mmol/L, 100mmol/L, 200mmol/ L, 300mmol/L, respectively, and the pH were 7.12, 8.01, 8.80 and 10.07, respectively. It was shown that, with the increase of stress, the relative germination and fresh weight decreased, leaf relative electrical conductivity and proline content increased. The SOD activity increased when stress started and reached to the peak at T3, and then decreased. Based on the means of parameters at T3 treatment, the membership function analysis and grey relation analysis were performed. The results showed that the association degree between different indices and comprehensive saline-alkali resistance indices was ranked as follows： proline content （0.95）, fresh weight （0.93）, leaf relative electrical conductivity （0.92）, SOD activity （0.92） and the relative germination （0.74）. The saline-alkali tolerance of 5 genotypes were finally ranked as Yajinl06〉 Yajin4589〉 Yajin2〉 Yajin4184〉 Yajinl0 based on the membership function analysis and Yajin2〉 Yajin106〉 Yajin4589〉 Yajin4184〉 Yajinl 0 based on grey relation analysis. These results indicated that the variation of saline-alkali tolerance was remarkable among the 5 genotypes. The fresh weight, leaf relative electrical conductivity, proline content and SOD activity were the reliable characteristics used for identification of sweet sorghum tolerant to saline-alkali stress. Yajin106 was the most tolerant genotype and Yajin10 was the least tolerant one among the tested materials.