盐胁迫对5种抗旱型小麦苗期生理特性的影响

【目的】探讨盐胁迫对不同抗旱型小麦品种苗期叶片抗氧化酶活性和相关生理指标的影响,为耐盐抗旱型小麦品种筛选和抗盐机制研究提供科学依据。【方法】选取5种抗旱型小麦品种(晋麦47、长4642、长6350、长6154和长6878),通过水培试验模拟不同盐胁迫处理(T1:Hoagland营养液+100 mmol/L Na Cl;T2:1/2浓度Hoagland营养液+200 mmol/L Na Cl;CK:1/2浓度Hoagland营养液)对小麦幼苗期的伤害效应,分别在胁迫第3 d和第7 d测定植株超氧化物歧化酶(SOD)和过氧化物酶(POD)活性及叶片丙二醛(MDA)和脯氨酸含量,分析不同抗旱型小麦对盐胁迫的响应差异。【结果】不同抗旱型小麦品种对不同盐胁迫浓度及胁迫时间的响应存在差异,其中晋麦47的叶片SOD活性在低盐浓度(T1处理)胁迫下被激活,随着盐浓度升高及胁迫时间延长,SOD活性又逐渐降低,叶片POD活性和MDA含量相对处于较低水平。方差分析结果表明,取样时间对小麦叶片SOD活性的影响极显著(P0.01,下同),叶片POD活性在不同盐胁迫处理、不同品种、采样时间及盐胁迫处理和品种互作间均存在极显著差异;叶片MDA含量在不同盐胁迫处理、不同品种和采样时间间存在极显著差异;脯氨酸含量在不同盐胁迫处理、采样时间间存在极显著差异。相关性分析结果表明,叶片MDA含量与SOD活性无明显相关性,而与POD活性及叶片和根系脯氨酸含量均呈极显著正相关。【结论】叶片POD活性和MDA含量可作为小麦的耐盐性筛选指标。5个抗旱型小麦品种中,晋麦47在苗期具有相对较强的耐盐性,适合在盐碱地推广种植。

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

Objective]Effects 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.Method]Five 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.Result]The 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.Conclusion]POD 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.