钠盐对冬小麦抗旱性增效作用调控机理的生理生态学分析

Ecological and Physiological Analysis of Effect of Different Types of Sodium Salt Treatment on Winter Wheat Resistance to Drought

以冬小麦(烟台-2070)为实验材料,苗期对冬小麦进行不同浓度钠盐(NaCl、Na2CO3、Na2SO4)处理,在随后进行的干旱胁迫和复水过程中进行叶片抗逆生理指标变化对比分析,以期探究盐处理在提高小麦抗旱性中的作用和生理调节机理,为未来干旱区农业实施盐水灌溉提供理论依据。实验采用盆栽法,将冬小麦种子盆栽,待长到第7天进行不同浓度钠盐(70mM,135mM,200mM,270mM)预处理8d,然后进行干旱胁迫12d和复水5d。分别在盐处理的第4天,第8天,干旱胁迫的第4天,第8天,第12天,以及复水第5天,从不同盐处理中采集冬小麦叶片,分析叶片相对含水量、丙二醛(MDA)、脯氨酸含量及抗氧化酶活力[超氧化物岐化酶(SOD)、过氧化氢(CAT)、过氧化物酶(POD)]的动态变化,同时测定土壤含水量。结果表明,在干旱胁迫过程中,未经盐处理的对照组和低浓度(70mM)NaCl、Na2CO3、Na2SO4溶液处理的土壤,土壤含水量急剧下降,同时冬小麦叶片相对含水量也相应的急剧下降;而用较高盐浓度处理的土壤和冬小麦叶片含水量降低较慢。在干旱胁迫过程中,对照组冬小麦在短时间(6d)内干旱叶片便出现萎蔫,并伴随着丙二醛、脯氨酸含量、SOD等抗氧化酶活力急剧增加并一直高于盐处理的冬小麦。相反高浓度盐处理的冬小麦在干旱处理12d时叶片直立生长良好,叶片MDA、抗氧化酶活力均增加,但增加幅度均低于对照。脯氨酸含量随干旱胁迫增加,但随盐处理浓度增加而上升幅度减小。在复水处理5d后,叶片含水量均增加,MDA和脯氨酸含量下降,但抗氧化酶活力仍增高。荒漠环境土壤中盐离子一方面可提高土壤和植物的保水率,提高水分利用率,另一方面激活体内的抗氧化酶系统使植物较早获得抗逆能力,这可能是荒漠植物多抗逆性形成的部分生理生化原因。

The effects of different concentrations of sodium salts（NaCl, Na2 CO3, Na2 SO4 ）on resistance of winter wheat （ Triticum aestivum） seedlings to drought were studied to analyze physiological mechanism of winter wheat tolerance increase to drought by salt stress treatment. The 7-day-old seedlings grown in pots were irrigated with sodium salt of different concentrations （70 mM, 135 mM, 200 mM, 270 mM）for 8 days, then were treated with drought stress for 12 days and rehydrated for 5 days. Then, the moisture con- tent in the leaves and soil, the activities of catalase （CAT）, peroxidase （POD） and superoxide dismutase （SOD）, MDA content and proline content were measured in the fresh leaves obtained at the 4th day and 8th day after salt stress, 4th day, 8th day and 12th day after drought stress, and 5th day after rehydration. Results showed that during the drought stress process, the moisture content in the leaves and soil rapidly declined with no salt and lower concentration （70 mM） NaC1, Na2CO3. Na2SO4 treatments, but the moisture content in the leaves and soil declined slowly with treatment of higher salt concentration under drought stress. With drought stress for 6 days, the leaves of winter wheat with no salt treatment became welting and had higher content of MDA and proline and activity of SOD than that with higher salt concentration treatment. But the plants with treatment of higher sodium salt concentration grew very well under drought stress for 12 days, and had lower increase level in the content of MDA and activities of antioxidant enzymes than that with no salt treatment. The proline content in the leaves increased with drought stress, but the increase level de- creased with the salt concentration increase. After rehydration for 5 days, there was an increase in leaf rela- tive water content, decrease in the contents of MDA and proline, and activities of antioxidant enzymes in the leaves maintained high level. There were no significant differences in increase of winter wheat resist- ance to drought between different types of sodium salt treatments. This study indicates that salinity in the soil plays an important role in formation of drought resistance of winter wheat because the solute in the cell can increase solute potential and make winter wheat hold more water, reduce the drought stress on cells, make plant survive longer under drought stress. This study also suggests that determination of optimum salt concentration is the key for the use of salinity water irrigation to hold higher output.