摘要
低浓度(0.1~1μmol/L)亚硒酸钠(Na_2-ScO_s)对烟草冠瘿组织的生长有促进作用;但浓度较高时(5~20μmol/L)不仅对生长有抑制作用,同时能促使其内源吲哚乙酸(IAA)和玉米素(ZA)含量下降,脱落酸(ABA)含量增加,IAA氧化酶活性增强。适宜浓度的外源2,4-D,IAA,6-BA,ZA都可部分缓解较高浓度Na_2SeO_3对生长的抑制作用,其中2,4-D,6-BA的缓解能力分别大于IAA和ZA。Na_2SeO_3还引起烟草冠瘿组织过氧化物同工酶谱发生显著变化,这种变化可被适宜浓度的外源6-BA逆转,并向正常组织方向转化,缓解较高浓度Na_2SeO_3对生长的抑制作用与逆转其过氧化物同工酶谱变化的6-BA浓度范围完全一致。
Sodium selenite at low concetration (0.0001~0.001 mmol/L) improved the growth of Nicotiana tabacum crown gall tissue, but inhibited it notably at higher concentrations (0.005~0.02 mmol/L). Sodium selenite decreased the level of endogenous IAA and zeatin, increased thelevel of endogenous ABA, and enhanced the activity of IAA oxidase. Exogenous 2,4-D, IAA, 6-BA or zeatin in suitable concentrations partially overcame the inhibitory effect of selenite on growth in higher concentrations, but the efficiency of exogenous IAA and zeatin were much lower than that of 2,4-D and 6-BA, respectively. The zymogram of peroxidase isozymes of the tissue also changed when treated with selenite, and these changes were reversed by exogenous 6-BA. These results im plied that the change of the growth of N. tabacum crown gall tissue induced by higher selenite concentrations may be due to its accelerating the oxidation of endogenous IAA and zeatin, as well as its raising the level of endogenous ABA.
关键词
烟草
冠瘿组织
内源激素
sodium selenite (Na_2SeO_2)
IAA
zeatin
2,4-D
ABA
6-BA
peroxidase isozymes