| 摘要: |
| 【目的】探讨碱胁迫对小冰麦有机酸积累和分泌的影响。【方法】将2种中性盐（NaCl和Na2SO4）和2种碱性盐（NaHCO3和Na2CO3）均按物质的量比1∶1混合，模拟出相同强度的盐、碱胁迫条件，并以其对小冰麦33的幼苗进行胁迫处理，计算日相对生长率，测定盐、碱胁迫下小冰麦幼苗茎叶中有机酸和无机离子的含量，分析根外pH及根分泌物中有机酸含量的变化。【结果】碱胁迫对小冰麦生长的抑制作用明显大于盐胁迫。碱胁迫引起小冰麦幼苗茎叶中Na+含量急剧增加，NO3-、SO2-4、H2PO-4含量明显降低，引起负电荷匮缺和离子不平衡。对照和盐胁迫处理小冰麦幼苗茎叶和根中有机酸均不积累，而碱胁迫可诱导有机酸急剧增加。小冰麦根系能够迅速降低碱胁迫下根外的pH。对照和盐胁迫下小冰麦分泌有机酸很少，而碱胁迫能明显刺激小冰麦根分泌有机酸。【结论】小冰麦可能通过积累有机酸来弥补负电荷不足，以保持细胞内pH稳定。分泌有机酸可能是小冰麦根外pH调节的重要途径。 |
| 关键词: 小冰麦 盐胁迫 碱胁迫 有机酸 分泌 pH调节 |
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| 基金项目:国家自然科学基金项目(30671491) |
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| Study on organic acids accumulation and secretion of alkali stress induced in wheat-wheatgrass |
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| Abstract: |
| 【Objective】The study was to probe into the inducing action of alkali stress on the accumulation and secretion of organic acids(OAs) in wheat-wheatgrass.【Method】Seedlings of wheat wheatgrass 33,an alkali salt wheat cultivar,were stressed with a range of salt stress (n(NaCl)∶n(Na2SO4)=1∶1) or alkali stress (n(NaHCO3)∶m(Na2CO3)=1∶1).Relative growth rate was calculated,the contents of organic acids and inorganic ions in shoots were measured,and the pH outside roots and the OAs in secretions were analyzed.【Result】The inhibiting effect of alkali stress on growth was greater than that of salt stress at the same salinity.Under alkali stress,Na+ greatly increased,and NO3-，SO2-4 and H2PO-4 decreased,causing a severe deficit of negative charge.In addition,OAs did not accumulate under control and salt stress,but their contents increased sharply under alkali stress.Under alkali stress,wheat-wheatgrass roots could easily lower pH of outside roots.Under control and salt stress wheat-wheatgrass roots released low concentrations of organic OAs.However,the OAs secretions of wheat-wheatgrass roots were significantly stimulated by alkali stress.【Conclusion】We propose that wheat-wheatgrass enhanced the synthesis of OAs,to compensate for the shortage of inorganic anions.OAs secretion was a specific adaptive mechanism of pH adjustment of outside roots under alkali stress. |
| Key words: wheat-wheatgrass(Triticum aestivum-Agropyron intermedium) salt stress alkali stress organic acid secretion pH adjustment |
