Despite significant recent advancement in research, biogeochemical behavior of heavy metals with respect to their applied form is still topical. Moreover, metal toxicity to plants may vary with their stage of development/maturity. Therefore, this study for the first time evaluated the influence of ethylenediaminetetraacetic acid (EDTA) and citric acid (CA) on cadmium (Cd) accumulation and toxicity to germinating and young pea seedlings as well as in younger and older leaves. The experimental setup of current study consisted of two separate studies. The first study was performed on germinating seedlings grown in a Cd-contaminated sand media. Pea seeds were treated with two levels of Cd (Cd-25 and Cd-100) alone and combined with different levels of EDTA and CA. The second study was carried out in hydroponic solution. The influence of organic amendments on Cd accumulation and toxicity to pea plants was evaluated by determining Cd contents in pea seedlings, H₂O₂ contents, chlorophyll contents and lipid peroxidation in younger and older leaves.

Cadmium stress caused overproduction of H₂O₂ in roots and leaves of pea seedlings. Cadmium-induced overproduction of H₂O₂ caused a decrease in the pigment contents and increased lipid peroxidation. Application of EDTA at higher levels (81 and 200 µM) increased Cd accumulation by pea plants. However, CA did not affect Cd accumulation by pea. Both EDTA and CA increased Cd-induced H₂O₂ production and lipid peroxidation. Younger pea leaves showed more sensitivity to Cd stress compared to older leaves. Similarly, Cd toxicity was more pronounced in germinating seedlings than young seedlings. Moreover, Pearson correlation and principal component analysis (PCA) showed very interesting correlations between treatments and stress responses of germination and young seedlings as well as younger and older leaves. Based on multivariate analysis, it is proposed that the Cd toxicity to pea plants greatly vary with its growth stage and the maturity of organs (younger or older leaves).

尽管最近研究取得了重大进展，但重金属的生物地球化学行为与其应用形式有关仍是热门话题。此外，金属对植物的毒性可能随其发育/成熟阶段而变化。因此，本研究首次评估了乙二胺四乙酸（EDTA）和柠檬酸（CA）对镉（Cd）积累以及对发芽和幼豌豆幼苗以及老幼叶片的毒性。当前研究的实验设置包括两个单独的研究。最初的研究是在Cd污染的沙土中生长的种子发芽。豌豆种子单独用两种水平的Cd（Cd-25和Cd-100）处理，并与不同水平的EDTA和CA结合使用。第二项研究是在水培溶液中进行的。幼叶和老叶中的₂ O ₂含量，叶绿素含量和脂质过氧化作用。

镉胁迫导致豌豆幼苗根和叶中H ₂ O _2的过量生产。镉诱导的H ₂ O ₂过量生产导致色素含量减少和脂质过氧化作用增加。较高浓度（81和200 µM）的EDTA施用增加了豌豆植物对Cd的积累。但是，CA不会影响豌豆对Cd的积累。EDTA和CA均增加了Cd诱导的H ₂ O ₂含量产生和脂质过氧化。与老叶相比，年轻的豌豆叶对镉胁迫表现出更高的敏感性。同样，发芽幼苗中的镉毒性比年轻幼苗更为明显。此外，Pearson相关和主成分分析（PCA）显示了发芽处理，幼苗和幼苗以及叶片的早老和衰老之间的处理和胁迫响应之间非常有趣的相关性。基于多变量分析，建议镉对豌豆植物的毒性随其生长阶段和器官（幼叶或老叶）的成熟程度而变化很大。