盐角草(Salicornia europaea)对NaCl处理的生理响应

用含有NaCl的Hoagland培养液处理盐角草(Salicornia europaea)11d。检测其鲜重,干重,离子含量,电导率,溶解性总固体(TDS)含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)浓度。结果表明:随着NaCl浓度的增加,盐角草干重和鲜重呈现先上升后下降的趋势,相对电导率、TDS、SOD、POD、CAT及MDA均呈现先下降后上升的趋势,在NaCl溶液浓度为200mmol·L-1左右时,干重和鲜重的值达到最大,电导率、TDS、SOD、POD、CAT、MDA含量达到最小值;500mmol·L-1和800mmol·L-1时,SOD和CAT活性下降,电导率、TDS、POD、MDA含量则急剧上升。由此说明,一定浓度的NaCl溶液促进了盐角草的生长,200mmol·L-1左右是其生长的最适浓度,500mmol·L-1和800mmol·L-1高盐浓度会对盐角草的膜结构、酶系统等造成不同程度的损伤。盐角草主要将Na+、K+积累在地上部,且随着NaCl处理浓度的增大,Na+含量逐渐增加、K+含量逐渐降低,这可能是盐角草调节细胞内离子平衡对抗盐胁迫的一种适应策略。

Responses of Physiological Traits of Salicornia european to NaCl Treatment

Salicornia europaea was treated with different NaCl (0,10,200,500,800 mmol·L^-1) for 11 days. The fresh weight (FW), dry weight (DW), ion contents, relative conductivity, total dissolved solids (TDS) content, the main antioxidant enzyme (SOD, POD,CAT) activities, and membrane lipid peroxide (MDA) were measured. Our results showed that the plant FW and DW peaked in 200 mmol·L^-1 NaCl treatment, accompanying with lowest values in relative electronic conductivity (EC), MDA and antioxidant enzyme (SOD, POD,CAT) activities, which indicated that this moderate NaCl concentration promote the growth of S. europaea. And the plant growth, FW and DW were reduced by higher or lower than 200 mmol·L^-1 NaCl treatment. The high level of NaCl (500 and 800 mmol·L^-1) treatments partly damaged plasma membrane and enzyme system, as showed by enhancement of MDA and EC values and by the reduction of antioxidant enzyme (SOD and CAT) activities. On the other hand, Na⁺ and K⁺ were mainly accumulated to shoot to adjust osmotic potential under salt stress, and Na⁺ content was much more than potassium. With increasing salinity, Na⁺ content increased while K⁺ content decreased in shoots and roots to regulate cellular ion balance. Hence, sodium may play more important role than potassium in regulating and tolerating salt stress.