不同倍性小麦对盐胁迫的适应性差异

Different adaptations to salt stress in different ploidies of wheat

关键词:  小麦, 异源多倍化, 盐胁迫, K⁺/Na⁺, 抗氧化系统

Key words:  wheat, allohexaploidization, salt stress adaptation, K⁺/Na⁺ ratio, antioxidant system

摘要:

为了揭示不同倍性小麦适应盐胁迫的差异,该研究以人工合成六倍体(AABBDD)小麦及其四倍体(AABB)小麦(Triticum turgidum)和二倍体(DD)节节麦(Aegilops tauschii)亲本为材料,研究了不同浓度NaCl(0、200 mmol·L^-1)胁迫处理下小麦幼苗K⁺、Na⁺含量以及K⁺/Na⁺的变化规律,以及不同浓度(0、50、100、200 mmol·L^-1)盐胁迫对超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性、丙二醛(MDA)含量、脯氨酸含量、可溶性蛋白和可溶性糖含量的影响规律。结果表明:四倍体表现出显著的高Na⁺低K⁺以及较低的K⁺ /Na⁺,二倍体表现出显著的低Na⁺高K⁺和较高的K⁺ /Na⁺,NaCl胁迫时离子含量变化大,对盐胁迫的适应性更强,六倍体在积累K⁺的能力上也有一定的优势。低浓度(50～100 mmol·L^-1)盐胁迫使3种倍性材料的丙二醛含量和抗氧化酶活性升高。四倍体在累积渗透调节物质和调节抗氧化酶活性的能力上显著强于二倍体和六倍体,六倍体在POD活性以及积累脯氨酸和可溶性蛋白的能力上也具有一定的优势。根据研究结果推测,含有DD染色体组的二倍体节节麦主要通过调节K⁺ /Na⁺来适应盐胁迫,而含有AABB染色体组的四倍体小麦主要通过调节抗氧化酶的活性累积渗透调节物质来适应盐胁迫,作为二倍体和四倍体远缘杂种的人工合成六倍体小麦则表现出了综合的耐盐适应性机制,相较于两亲本具有更加广泛耐盐适应性。

Abstract:

In order to investigate different adaptions to salt stress in different ploidies of wheat, K⁺ and Na⁺ content, K⁺/Na⁺ ratio, the activity of SOD, CAT, POD and the contents of MDA, soluble protein, and soluble sugar were analyzed in synthetic hexaploid(AABBDD)wheat and its tetraploid(AABB)wheat(Triticum turgidum)and diploid(DD)(Aegilops tauschii)parents after treated with 0, 50, 100, and 200 mmol·L^-1 NaCl. The results showed that tetraploid wheat had the highest concentration of Na⁺ , the lowest concentration of K⁺ and a low K⁺ /Na⁺, diploid wheat had the highest concentration of K⁺ , the lowest concentration of Na⁺ and high K⁺ /Na⁺. The change of K⁺ and Na⁺ in diploid wheat was more obvious than that in tetraploid and hexaploid synthetic wheat under salinity stress. The hexaploid synthetic wheat showed a relative advantage of accumulating K⁺ compared with tetraploid wheat. Low concentration of NaCl(50 and 100 mmol·L^-1)stress stimulated the accumulation of MDA and increase of antioxidant enzyme activity in three ploidies of materials. The tetraploid wheat showed a significant superiority to accumulate osmotic adjustment substances and kept higher activity of antioxidant enzymes than diploid and hexaploid materials. Meanwhile, hexaploid synthetic wheat displayed a strong ability of accumulating soluble protein and proline as well as enhancing POD activity. Our results suggested that the diploid containing DD genome may mainly adapt to salt stress by regulating K⁺ /Na⁺ ratio while the tetraploid containing AABB genome may mainly adapt to salt stress by regulating antioxidant enzyme activity and accumulating more osmotic adjustment substances. The hexaploid synthetic wheat containing AABBDD exhibited the comprehensive adaptation mechanisms to salt stress, may express a broader adaptation ability to salt stress compared with the tetraploid and diploid parents.