Bio-Physiologie Cellulaires, Département des Sciences de la vie, Faculté des Sciences de Bizerte, 7021 Zarzouna, Tunisia.
Ecotoxicol Environ Saf. 2010 Sep;73(6):1123-9. doi: 10.1016/j.ecoenv.2010.01.005. Epub 2010 Feb 6.
The germination rate, mineral (Ca, Fe, K, Mn) and carbohydrate (starch, soluble sugars, sucrose, glucose, fructose) contents and hydrolase activities in cotyledons and embryonic axes of bean seeds subjected to cadmium stress were investigated. Compared to the control, Cd caused a reduction in germination percent, embryo growth and in distribution of biomass, mineral and sugars between cotyledon and embryonic axis and inhibited the activities of alpha-amylase and invertases: soluble acid (INV-AS), soluble neutral (INV-NS), cell wall bound acid (INV-AW). Moreover, the solute leakage into the germination medium was also used as bioindicator parameter to evaluate the toxicity of cadmium accumulation, which increased in different tissues of germinating seeds in the duration of treatment and provoked nutrient loss and, thereby, electrical conductivity enhancement in the imbibition medium. This was correlated with an impairment of membrane integrity, as evidenced by high malondialdehyde (MDA) content and lipoxygenase (LOX) activity in Cd-poisoned embryo. The contribution of solute loss at the expense of growing embryonic axis to failure in reserve mobilization after Cd exposure is emphasized in association with the delay in seed germination.
研究了镉胁迫下的豆种子子叶和胚轴中的发芽率、矿物质（Ca、Fe、K、Mn）和碳水化合物（淀粉、可溶性糖、蔗糖、葡萄糖、果糖）含量以及水解酶活性。与对照相比，Cd 降低了发芽率、胚的生长以及生物量、矿物质和糖在子叶和胚轴之间的分布，并抑制了α-淀粉酶和转化酶的活性：可溶性酸性（INV-AS）、可溶性中性（INV-NS）、细胞壁结合酸性（INV-AW）。此外，溶质渗漏到发芽介质中也被用作生物指标参数来评估镉积累的毒性，这种毒性在处理过程中不同组织的发芽种子中增加，并导致营养物质损失，从而增强了浸种介质的电导率。这与膜完整性的损害有关，如丙二醛（MDA）含量和脂氧合酶（LOX）活性在 Cd 中毒胚胎中升高所证明的那样。强调了由于胚轴生长而导致溶质损失对 Cd 暴露后储备动员失败的贡献，这与种子发芽延迟有关。
