苗期盐穗木在不同盐浓度处理下的渗调和抗氧化系统

Osmotic and Antioxidant System in Halostachys caspica Seedlings under Salt Stress

拟通过对盐穗木2月龄幼苗和6月龄成苗在不同Na Cl浓度（0、100、300 mmol·L^（-1）和500 mmol·L^（-1））处理15 d后的相对含水量、脂质过氧化物（MDA）、无机（Na＋、K＋和Ca^（2＋））和有机渗透调节物质（脯氨酸和甜菜碱）及抗氧化指标（SOD、CAT、APX、POD、As A和GSH）的检测,分析并比较盐穗木不同发育阶段应对不同盐浓度的渗透调节和抗氧化防御系统,为盐穗木的研究与开发利用以及新疆生态环境的治理提供依据。结果表明：500 mmol·L^（-1）高盐胁迫下,盐穗木幼苗和成苗相对含水量与对照组相比均显著下降;结合相对含水量和MDA含量显示,100mmol·L^（-1）和300 mmol·L^（-1）Na Cl均未对盐穗木造成胁迫;渗透调节系统中,无机离子Na＋和有机物质甜菜碱（GB）分别在盐穗木幼苗和成苗的渗透调节中发挥主导作用;抗氧化系统中,除盐穗木成苗在500 mmol·L^（-1）处理下抗坏血酸（As A）含量升高外,超氧化物歧化酶（SOD）和CAT活性及谷胱甘肽（GSH）含量随盐浓度的增加一直保持较高水平且变化很小;相关系数分析显示As A和SOD分别在盐穗木幼苗和成苗中发挥了重要的抗氧化作用。由此可见,新疆牧草盐穗木在苗期的不同生长阶段采用不同的渗透调节和抗氧化策略应对盐渍生境。

The objective of this research was to better understand the mechanism of osmoregulation and antioxidant response of Halostachys caspica seedlings growing under salt stress.The effects of Na Cl-salinity treatments（0,100,300 and 500 mmol·L^（-1）Na Cl for 15 days）on water content,lipid peroxidation（MDA）,organic（proline and glycine betaine）and inorganic osmolytes（Na＋,K＋and Ca^（2＋））,and antioxidant defenses（SOD,CAT,APX,POD,As A and GSH）in seedlings and grown-up seedlings of H.caspica were investigated.The research on the development and utilization of H.caspica and the improvement of ecological environment in Xinjiang was carried out.Water content in the seedlings and grown-up seedlings of H.caspica growing under high-salt（500 mmol·L^（-1）Na Cl）stress was significantly decreased compared with those under control.The data of water content and MDA content revealed that asalt stress on H.caspica plants was not induced under the conditions of 100 mmol·L^（-1）and 300mmol·L^（-1）Na Cl.Na＋and GB played the dominant roles in osmoregulation of seedlings and grown-up seedlings.With increasing salt concentration,the activities of SOD and CAT as well as the content of GSH were maintained at a high level all along except As A content of grown-up seedlings under 500 mmol·L^（-1）Na Cl treatment was increased.The correlation coefficient analysis showed that As A and SOD played an important role in antioxygenation of seedlings and grown-up seedlings of H.caspica.It could be seen that the osmotic adjustments and antioxidant strategies were different at different growth stages of H.caspica seedlings so as to adapt salt stress.