Abstract:

Drought is one of the limiting factors for plant growth and development, and therefore the cloning and function study of novel drought-tolerant genes is very necessary. To determine the suitable concentration, medial lethal concentration, and lethal concentration of mannitol, four different irradiation doses for White clover Rivendel variety were selected in vitro screening. The mutants were identified by measuring height, root length, biomass, chlorophyll, MDA, Pro, SOD, POD, and comparing the difference between the mutation materials and the original materials. Besides, four materials' drought tolerance was evaluated by using the standard deviation coefficient of weighted method. The results showed that 20Gy mutagenic materials and 80Gy mutagenic materials had higher medial lethal concentration and lethal concentration than original material. Through comprehensive evaluation, the drought tolerance order of four materials from strong to weak was 20Gy, 90Gy, 80Gy, 0Gy, respectively. It meant the drought tolerance of all mutagenic materials was stronger than original material. The study provides a basis for the cloning and functional analysis of drought-resistant genes, and has important theoretical significance to reveal the molecular mechanisms of the drought tolerance of plant.

Key words: White clover, ⁶⁰Co-&gamma, mutagenesis, Drought resistance mutants, Mannitol

摘要：

干旱是植物生长和发育的限制因素之一，因此抗旱基因克隆和功能研究具有应用价值。本试验以甘露醇为选择剂，对⁶⁰Co-γ诱变白三叶瑞文德品种（Trifolium repens ‘Rivendel’）4个辐照剂量下的植株进行抗旱突变体的离体筛选，确定4份植株对甘露醇的适宜浓度、半致死浓度和致死浓度，通过测定株高、根长、生物量、叶绿素、丙二醛（MDA）、脯氨酸（Pro）、超氧化物歧化酶（SOD）、过氧化物酶（POD），比较诱变植株与未诱变植株耐旱性的差异，采用标准差赋予权重法对4份植株的耐旱性进行综合评价。结果表明：诱变植株20 Gy和80 Gy对甘露醇具有比未诱变植株0 Gy更高的半致死浓度和致死浓度。通过4份植株的耐旱性综合评价得出：4份植株的耐旱性由强到弱依次为：20 Gy > 90 Gy > 80 Gy > 0 Gy，诱变植株的耐旱性均强于未诱变植株。该研究为抗旱基因克隆及功能分析奠定基础，对揭示植物抗旱的分子机理具有重要的理论意义。

关键词: 白三叶, ⁶⁰Co-&gamma, 诱变, 抗旱突变体, 甘露醇