NaCl胁迫对小黄花菜生长及相关生理指标的影响

Effects of NaCl stress on growth and related physiological indexes in Hemerocallis minor

关键词:  小黄花菜, NaCl胁迫, 渗透调节, 生长, 质膜透性

Key words:  Hemerocallis minor, NaCl stress, osmoregulation substance, growth, membrane permeability

摘要:

为探讨小黄花菜的耐盐机理,选育良好的耐盐植物以缓解土壤盐渍化问题,该文选取小黄花菜(Hemerocallis minor)为试材,采用砂培法,研究不同浓度NaCl(50、100、150、200、250 mmol·L^-1)胁迫对小黄花菜的生长性状、细胞质膜透性和有机渗透调节物质含量等的影响。结果表明:(1)小黄花菜在100～150 mmol·L^-1NaCl胁迫时,损害初步显现,但不影响其存活; 在Nacl浓度为200 mmol·L^-1以上时,小黄花菜生长被显著抑制,造成根系不发育、叶片受害、植株干物质积累显著不足,严重影响其生存状态。(2)50～150 mmol·L^-1盐渍环境下,叶片膜透性、MDA含量增幅较小,该浓度范围的NaCl胁迫造成的膜脂损伤有限; 200 mmol·L^-1以上浓度的NaCl胁迫使得小黄花菜叶片的离子平衡无法继续维持,膜的选择透性丧失。(3)随着NaCl浓度的增加,叶片中脯氨酸含量显著增加; 50～100 mmol·L^-1 Nacl胁迫下,叶片可溶性糖含量在胁迫初期有所增加,在15 d时达到最大,胁迫后期开始下降; 叶片中可溶性蛋白含量的变幅较为平缓,说明小黄花菜的主要渗透调节物质不是可溶性蛋白。该研究发现通过提高叶片膜透性,促进自身有机渗透调节物质的合成,能够在一定程度上缓解盐渍对植株的侵害,使得小黄花菜能够在50～100 mmol·L^-1的盐碱环境下正常生长。

Abstract:

We explored the salt tolerance mechanism of Hemerocallis minor to be able to select good salt-tolerant plants and alleviate the problem of soil salinization. Using a sand culture method, we analyzed how different concentrations of NaCl stress(0, 50, 100, 150, 200, 250 mmol·L^-1)influence the growth characteristics, cytoplasmic membrane permeability, and organic osmotic adjustment substance content. The results were as followers:(1)The damage to H. minor began at an exposure of 100-150 mmol·L^-1 of NaCl, but did not affect survival. Growth was significantly inhibited at concentrations above 200 mmol·L^-1. Side effects at this concentration included: root system underdeveloping, damaged leaves, and insufficient dry matter accumulation, which seriously affected plant survival status.(2)Under 50-150 mmol·L^-1 of NaCl stress, the cell membrane permeability and MDA content increased slightly. NaCl stress at this concentration range causes limite amounts membrane lipid damage. NaCl stress above 200 mmol·L^-1 makes it impossible to maintain ion balance and the selective permeability of the membrane is lost.(3)we found that as the concentration of NaCl increases, the content of proline in the leaves increased significantly. Under 50-100 mmol·L^-1 of NaCl stress, the soluble sugar content increased at the initial stage of stress, and reached its maximum on 15 d. Soluble sugar content began to decrease at a later period and the soluble protein content in the leaves changed more slowly. This indicated that the main osmotic adjustment substance in H. minor was not soluble protein. Studies have found that H.minor can alleviate salt damage to plants by improving cell membrane permeability and promoting the synthesis of organic osmotic adjustment substances. This allows for H. minor to grow normally in saline-alkali soil under 50-100 mmol·L^-1.