尖叶石竹蜡质突变体的耐盐生理响应

盐胁迫会引起植物的渗透胁迫、离子毒害，导致细胞失水、光合和呼吸作用受到抑制，进而影响植物的生长和发育。植物表皮蜡质可以阻止叶片的非气孔失水，减少蒸腾，减缓植物因胁迫而引起的生理干旱。本研究以观赏性草坪草尖叶石竹(Dianthus spiculifolius)的野生型(wild-type, WT)和表皮蜡质增强突变体(wax mutant, WM)为材料，比较了两者在NaCl胁迫下的表型和生理生化指标的变化规律。结果表明：蜡质突变体在NaCl胁迫下维持了更高的水分含量从而表现出更好的耐盐表型。此外，蜡质突变体在NaCl胁迫下显示出更高的过氧化物酶和过氧化氢酶活性、可溶性糖含量、脯氨酸含量、光合能力以及更低的丙二醛含量。脱蜡试验显示，蜡质突变体与野生型在盐胁迫下的相对含水量和持水力差异与表皮蜡质直接相关。本研究表明表皮蜡质在植物应答盐胁迫中具有重要作用。

Physiological response to salt tolerance of a waxy mutant of Dianthus spiculifolius

Salt stress can cause osmotic stress and ion toxicity, leading to cell dehydration, inhibition of photosynthesis and respiration, and further effects on the growth and development of plants. Plant cuticular wax can prevent non-stomatal water loss from leaves, reduce transpiration, and slow down physiological drought caused by stress. In this study, the wild-type (WT) and a mutant with increased cuticular wax (WM) of Dianthus spiculifolius ornamental ground-cover species were used, and their phenotypic, physiological, and biochemical indicators under NaCl stress were compared. The results showed that, under NaCl stress, the waxy mutant showed a more salt-tolerant phenotype resulting from its higher water content. In addition, the waxy mutant showed higher peroxidase (POD) and catalase (CAT) activity, soluble sugar content, proline content, photosynthetic capacity, and lower malondialdehyde (MDA) content under NaCl stress. Dewaxing experiments showed that the difference in relative water content and water retention between the waxy mutant and the wild-type under NaCl stress was directly related to cuticular wax. These results suggest that cuticular wax plays an important role in the plant’s response to salt stress.