镉处理对大豆幼苗生长及激素含量的影响

采用室内培养试验,通过测定植株生理生化指标,研究了不同浓度Cd²⁺处理对大豆幼苗生长及激素含量的影响.结果表明:①不同浓度Cd²⁺处理对大豆幼苗地下部生长素(IAA)和赤霉素(GA₃)的合成有抑制效应,对地上部生长素(IAA)和赤霉素(GA₃)的合成具有低浓度下的刺激效应和高浓度下的抑制效应;对地下部、地上部玉米素(Z)和脱落酸(ABA)的合成均有刺激效应.②Cd²⁺处理84h对大豆幼苗根系活力、叶绿素a和叶绿素b的合成有刺激效应,对类胡萝卜素的合成无影响.③Cd²⁺处理对过氧化物酶(POD)活性和丙二醛(MDA)含量具有低浓度下的抑制效应和高浓度下的激活效应,且随着Cd²⁺浓度的增加激活效应逐渐加强.④短时间、低浓度Cd²⁺胁迫可刺激大豆幼苗的生理活性,以Cd²⁺处理浓度为0.50 mg/L时,大豆幼苗根系活力最大,IAA和GA₃含量最高,POD活性最低,植物生理活性最强.

Effects of Cd2+ on Seedling Growth and Phytohormone Contents of Glycine max

A laboratory incubation experiment was conducted to study the effects of different Cd²⁺ concentrations on seedling growth and phytohormone contents of Glycine max through determining some physiological and biochemical indexes. The results showed as follows: (1) Different Cd²⁺ concentrations inhibited the synthesis of indoleacetic acid (IAA) and gibbrellins (GA₃) in roots and stimulated the synthesis of zeatin (Z) and abscisic acid (ABA) not only in roots but also in aerial parts of Glycine Max. Cd²⁺ stimulated the synthesis of IAA and GA₃ in aerial parts at lower concentrations, but inhibited the synthesis of IAA and GA₃ at higher concentrations. (2) At the initial stage of Cd²⁺ stress, the root vitality increased, as well as the contents of chlorophyll a and b, but no significant difference was found in carotinoid contents compared with the control. (3) Cd²⁺ stress decreased POD activities and MAD contents at lower concentrations and increased POD activities and MAD contents at higher concentrations. With increasing Cd²⁺ concentrations, this increase became significant gradually. (4) Cd²⁺ stress with lower concentrations stimulated the physiological activity of Glycine max seedling in a short time. When Cd²⁺ concentration was 0.50 mg/L, the root vitality, IAA and GA₃ contents of Glycine max were the highest, and POD activity was the lowest.