耐盐浮萍品种筛选及耐盐机制研究

Screening of Salt-tolerant Duckweed Germplasm and Deciphering Mechanisms of Its Salt Tolerance

浮萍是一种漂浮在水面上生长的单子叶植物,具有高淀粉、高蛋白质及氨基酸种类齐全等特征,在淀粉和蛋白质利用领域具有广阔的应用前景。为了获得耐盐性较强的品种用于盐碱地开发,利用NaCl溶液(200 mmol/L)筛选耐盐浮萍种质资源,得到耐盐品种(‘Lemna 6204’和‘Lemna 6101’)和盐敏感品种(‘Lemna 6014’和‘Lemna 6008’)各两个。为探讨浮萍的耐盐机制,研究了NaCl胁迫后不同耐盐性品种的生理差异,结果表明:与盐敏感品种相比较,NaCl胁迫后耐盐品种叶状体呈深绿色且保持较好的生长状态;进一步研究发现叶绿素a和叶绿素b含量下降幅度明显低于盐敏感品种,耐盐品种的细胞损伤程度显著低于盐敏感品种。此外,耐盐品种仍维持较高的过氧化氢酶和过氧化物酶活性,脯氨酸含量显著增加,但丙二醛含量几乎没有变化。上述结果表明:浮萍品种‘Lemna 6204’和‘Lemna 6101’具有较强的耐盐性,这将为盐碱地水面资源的开发利用提供耐盐种质资源。

Duckweed is a floating aquatic plant,which is monocots and is high in starch and protein,and contains all essential amino acids.Therefore,it will have broad application prospects in the field of starch and protein utilization.Obtaining salt-tolerant duckweed varieties will be of benefit for the sustainable development of saline-alkali land.In this study,we used NaCl solution(200 mmol/L)to screen salt-tolerant duckweed germplasm resources,and obtained two salt-tolerant varieties(‘Lemna 6204’and‘Lemna 6101’)and two salt-sensitive varieties(‘Lemna 6014’and‘Lemna 6008’).To explore the salt tolerance mechanism,we studied the physiological differences of different varieties after NaCl treatment.Compared with salt-sensitive varieties,salt-tolerant varieties had dark green fronds and grew well.Further physiological analysis showed that the decrease of chlorophyll a and chlorophyll b content and the degree of cell damage of salt-tolerant varieties were significantly lower than those of salt-sensitive varieties.In addition,salt-tolerant varieties had high levels of catalase and peroxidase activity,with a significant increase in proline content,but little change in malondialdehyde content.The above results indicated that duckweed varieties‘Lemna 6204’and‘Lemna 6101’displayed a strong resistance to salinity,which could provide salt-tolerant germplasm resources for the development and utilization of water surface resources in saline-alkali lands.