盐胁迫对苗期湖南稷子K+、Na+含量与分布的影响

以湖南稷子(Echinochloa frumentacea)为材料,设置不同浓度(0、25、50、75、100、125、150、200 mmol·L-1)的NaCl和Na2 SO4作为胁迫处理,探讨盐胁迫对湖南稷子苗期K+、Na+吸收与分布特性的影响.结果表明,随着NaCl和Na2 SO4浓度的增加,湖南稷子叶片、茎鞘...

Effects of NaCl and Na2SO4 stress on content and distribution of K + and Na + of Echinochloa frumentacea seedlings

In order to explore the characteristic of K ⁺ and Na ⁺ absorption and distribution at seedling stage of Echinochloa frumentacea under salt stress. The variety Haizi-1 was used as test material, eight different concentrations (0, 25, 50, 75, 100, 125, 150, 200 mmol·L ^-1) of NaCl and Na₂SO₄ were set to simulate conditions of salt stress in this study. The results showed that with the increase of NaCl and Na₂SO₄ concentration, Na ⁺ content was increased, K ⁺ content was decreased, K ⁺/Na ⁺ ratio were all decreased in leaf, stem sheath and root; Content and distribution of Na ⁺ was root>stem sheath>leaf, Na ⁺ content in leaf and stem sheath were significantly lower than that in root. K ⁺/Na ⁺ ratio in leaf and stem sheath was higher than that in root. Content and distribution of K ⁺ was stem sheath>root>leaf under low salt concentration, and under the medium and high salt concentration, content and distribution of K ⁺ was stem sheath>leaf>root. Transport selectivity coefficient from root to stem sheath of K ⁺ and Na ⁺ (ST1_{K, Na}) and transport selectivity coefficient from stem sheath to leaf of K ⁺ and Na ⁺ (ST2_{K, Na}) under salt stress were significantly higher than those of the control at salt concentration>25 mmol·L ^-1, and ST1_{K, Na} was higher than ST2_{K, Na}. When the salt concentration was≥125 mmol·L ^-1, K ⁺/Na ⁺ ratio became stable in above ground under Na₂SO₄ stress, K ⁺ content in stem sheath and root and ST1_K,Na were higher than those under the same concentration of NaCl stress, and Na ⁺ content in leaf and stem sheath were lower than that under the same concentration of NaCl stress. ST2_{K, Na} showed an upward trend under Na₂SO₄ stress, and increased firstly and then decreased under NaCl stress. In conclusion, it had been shown that under salt stress, root system of E. frumentacea had a strong restriction on sodium ion transport to the above-ground part and had higher selective absorption capacity for K ⁺, and it had more tolerance to Na₂SO₄ stress than NaCl stress under higher concentration of salt stress.