渗透胁迫和离子毒害对转Bt基因棉幼苗生长及离子分布的影响

研究了渗透和盐胁迫处理对转Bt基因抗虫棉(Gossypium hirsutum) 99B种子的萌发和幼苗生长的影响,以及幼苗不同器官离子吸收和分配的差异。结果表明:渗透和盐胁迫均对转Bt基因抗虫棉幼苗的生长有抑制作用,其中PEG的抑制作用最强,而3种盐的抑制程度以CaCl₂>NaCl>Na₂SO₄,且在Na⁺含量相同时,Cl^-的毒害大于SO₄^2-。渗透胁迫下使根、茎和叶中的Na⁺和Cl^-含量提高,K⁺、Ca²⁺、SO₄^2-含量和K⁺/Na⁺、Ca²⁺/Na⁺和SO₄^2-/Cl^-比值降低,且地上部的变化幅度大于地下部的,其中以PEG的影响最为显著,其次是CaCl₂,Na₂SO₄处理最弱。这些说明,转Bt基因抗虫棉99B的耐盐性较弱。

Effects of Osmotic Stress and Ionic Toxicity on Growth and Ion Allocation in Transgenic Bt Cotton Seedlings

The seeds of transgenic Bt cotton (Gossypium hirsutum L.) 99B were treated with osmotica and salt solution, such as CaCl₂, NaCl, Na₂SO₄ and PEG (6000), the effects of osmotic and salt stresses on the growth and ion allocation in cotton seedlings were studied. The results showed that the growth of transgenic Bt cotton seedlings were inhibited under stresses, in which PEG had the most significant effect, and the inhibition effects of three kinds of salt was in order as CaCl₂>NaCl>Na₂SO₄. Toxicity of Cl^- was greater than SO₄^2- under the same content of Na⁺. Under osmotic stress, the contents of Na⁺ and Cl^- in the roots, stems and leaves increased, but the contents of K⁺, Ca²⁺ and SO₄^2- and K⁺/Na⁺, Ca²⁺/Na⁺and SO₄^2-/Cl^- decreased, and the change range of ion contents in aerial part was greater than those in under-ground part. The effect of PEG on ion contents was the most significant, followed by CaCl₂, and Na₂SO₄ was the weakest. It suggested that the transgenic Bt cotton had low salt tolerance.