Effects of salt stress on physiological characteristics of five drought resistant wheat cultivars at seedling stage

ObjectiveEffects of salt stress on activities of antioxidative enzymes and related physiological indexes in leaves of various drought resistant wheat cultivars at seedling stage were investigated in order to provide reference for sellection of salt tolerant and drought resistant wheat cultivars and further study on salt tolerant mechanism.MethodFive drought resistant wheat cultivars(including Jinmai 47,Chang 4642,Chang 6350,Chang 6154 and Chang 6878) were used as materials. Water culture experiment was conducted to simulate different salt stress treatments(T1:Hoagland nutrient solution+100 mmol/L NaCl;T2:1/2 concentration of Hoagland nutrient solution+200 mmol/L NaCl;CK:1/2 concentration of Hoagland nutrient solution). The harm of salt stress to wheat at seedling stage was observed. To indentify the response of different drought resistant wheats to salt stress, superoxide dismutase(SOD)activity,peroxidase isoen-zymes(POD)activity,malondialdehyde(MDA)content and proline in plants were determined on day 3 and day 7 under salt stress.ResultThe responses of different drought resistant wheats to salt stress at various concentrations and stress times were different. For Jinmai 47 ,activities of SOD were activated under lower level of salt stress(T1),but were decreased as salt stress concentration increased and stress time prolonged. However,leaf POD activity and MDA content remained at low level. The variance analysis showed that sampling time significantly influenced leaf SOD activity(P<0.01,the same below). Salt stress levels,wheat cultivars and sampling time extremely significantly influenced leaf POD activity. Leaf MDA contents were significantly influenced by salt stress concentrations,wheat cultivars and sampling time. Proline contents were extremely significantly influenced by salt stress concentration and sampling time. Correlation analysis indicated that contents of leaf MDA were not obviously related to SOD activity,POD activity was extremely positively related to proline content.ConclusionPOD activity and MDA content can be used as physiological indexes to identify the ability of salt-tolerance for wheat. Among the five wheat cultivars,Jinmai 47 has strong salt tolerance at seed-ling stage and therefore is suitable to be planted in saline land.