NaCl胁迫下玉米黄化苗质外体和共质体Na、Ca浓度的变化

Changes in Na and Ca Concentrations in the Apoplast And Symplast of the Etiolated Corn Seedlings under NaCl Stress

低浓度NaCl短期处理促进玉米黄化苗根和地上部分的伸长生长,高浓度NaCl短期胁迫则抑制根和地上部分的伸长生长。根和地上部分的含水量在本实验条件下并不受NaCl胁迫的影响。而根和地上部分总Na含量随NaCl浓度的增加和胁迫时间的延长而增加,总Ca含量则下降。NaCl胁迫下,根和地上部分质外体和共质体中Na含量均明显增加,但质外体中Na含量增加更为明显,150mol/m^3NaCl胁迫24小时,根中质外体Na含量高达738.9mol/m^3,共质体Na含量只有68.1mol/m^3,分别比对照增加了34.0倍和8.4倍。NaCl胁迫下,地上部分质外体和共质体Ca含量均下降,但根质外体Ca含量在一定NaCl胁迫范围内却增加,超过一定范围则下降,根共质体Ca含量在NaCl胁迫下均下降。本文讨论了质外体和共质体Na、Ca含量在植物耐盐性中的作用。

The elongation rate of the roots and shoots of the etiolated corn seedlings were stimulated when subjected to mildly saline(50 mol/m3 NaCl for 1,6 and 24 h),but inhibited when subjected to high concentration of NaC1(l00 and 150 mol/m3 for 1, 6 and 24 h). Water content of the roots and shoots were not significantly altered by NaCl stress under the condition of the paper. Total Na concentration of the roots and shoots increased under NaCl stress, but total Ca decreased. Na concentration in apoplast of roots and shooots both increased under NaCl stress, and it increased much higher in apoplast of roots than in that of shoots. Ca concentration in apoplast and symplast of the shoots declined under all of the levels of NaCl stress, But Ca concentration in apoplast of the roots increased under certain extent of NaCl stress and decreased above an extent of NaCl stress. The Ca concentration in symplast of roots declined under NaCl stress. The functions of Na and Ca in apoplast and symplast in salt tolerance were discussed.