盐胁迫对盐芥（Thellungiella halophila）生长和抗氧化酶活性的影响

在盐芥抽苔期用不同浓度NaCl进行处理，测定单株生长量、苔茎叶和根系的质膜透性、MDA含量、苔茎叶的超氧阴离子（O^-₂）含量，苔茎叶的超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）等的活性。结果表明：低浓度NaCl处理盐芥单株干重增加，高浓度NaCl处理则降低盐芥单株的干重，鲜重有抑制作用；盐处理后盐芥地上部质膜透性逐渐增加，地下部质膜透性、叶片中的丙二醛（MDA）和超氧阴离子（O^-₂）含量先降低后升高。抗氧化酶系统中的超氧化物歧化酶（SOD）活性先升高后降低，过氧化物酶（POD）、过氧化氢酶（CAT）的活性呈上升趋势。表明低浓度的盐处理对盐芥生长有利，活性氧及丙二醛（MDA）含量减少，而高浓度的盐处理后，抗氧化酶不能及时将活性氧类清除，从而导致活性氧及MDA积累，引起质膜伤害，盐芥生长量降低。

Effects of salt stress on the growth and the antioxidant enzyme activity of Thellungiella halophila

Thellungiella halophila in its bulting stage was treated with NaCl of different concentration, determining relevant parameters, including the growth amount, the height of single plant, the number of branches and leaves, the membrane leakage, the MDA contents of stem leaves and roots, the superoxide anion（O^-₂）content, the activities of superoxide dismutase (SOD), peroxidase (POD) and calatase (CAT) of stem leaves. The result showed the NaCl lower concentration treatment benefited the fresh and dry weights of T. halophila, but the NaCl higher concentration treatment inhibited those of T. halophila; NaCl treatment made the membrane leakage of leaves increased, the lower concentration NaCl treatment brought about the decrease of membrane leakage of roots, the malondialdehyde (MDA) and O^-₂ contents of leaves while the higher concentration of those made them increased compared with the control plants; the lower concentration of NaCl treatment led to the increase of superoxide dismutase activity (SOD) compared with the control plants, the higher concentration of NaCl treatment brought about the SOD activity decrease, the peroxidase (POD) and calatase (CAT) activities increased after NaCl was treated with different concentration. It proved that lower NaCl concentration treatment benefited the growth of T. halophila, the reactive oxygen species and MDA content decreased; and the NaCl higher concentration treatment, the system of scavenging reactive oxygen species(ROS) coundn’t scavenge the ROS in time, which caused the accumulation of ROS and the damage of membrane, which in turn caused the accumulation of MDA, so the growth of T. halophila was inhibited.