Bio-Physiologie Cellulaires, Département des Sciences de la Vie, Faculté des Sciences de Bizerte, 7021 Zarzouna, Tunisia.
J Hazard Mater. 2010 Jun 15;178(1-3):1128-31. doi: 10.1016/j.jhazmat.2010.01.115. Epub 2010 Feb 1.
Seed germination represents a limiting stage of plant life cycle under heavy metal stress situation. Delay in germination can be associated with disorders in the event chain of germinative metabolism which is a highly complex multistage process, but one of underlying metabolic activities following imbibition of seed is the storage mobilization. The influence of cadmium on carbohydrates and aminoacids export from cotyledon to embryonic axis during germination of pea seed was investigated. Compared to the control, Cd caused a restriction in reserve mobilization as evidenced by the pronounced increase in cotyledon/embryo ratios of total soluble sugars, glucose, fructose and aminoacids. Moreover, the nutrient concentrations, as well as the electrical conductivity of germination medium were determined to quantify the extent of solute leakage. Such nutrients were lost into the imbibition medium at the expense of suitable mobilization to the growing embryonic axis. This was concomitant with an over-accumulation of lipid peroxidation products in Cd-poisoned embryonic tissues. However, the impairment of membrane integrity cannot be due to a stimulation in lipoxygenase activity, since the later was markedly inhibited after Cd exposure.
种子萌发是植物生命周期中在重金属胁迫情况下的一个限制阶段。萌发的延迟可能与萌发代谢事件链中的紊乱有关，该事件链是一个高度复杂的多阶段过程，但在种子吸胀后，潜在的代谢活动之一是储存动员。研究了镉对豌豆种子萌发过程中从子叶到胚轴的碳水化合物和氨基酸输出的影响。与对照相比，Cd 导致储备动员受限，表现为总可溶性糖、葡萄糖、果糖和氨基酸的子叶/胚轴比显著增加。此外，还测定了营养浓度和发芽介质的电导率，以量化溶质渗漏的程度。这些养分以牺牲向生长中的胚轴适当动员为代价而流失到吸胀介质中。这与 Cd 中毒胚组织中脂质过氧化产物的过度积累同时发生。然而，膜完整性的损伤不能归因于脂氧合酶活性的刺激，因为 Cd 暴露后后者明显受到抑制。
