Lead is a hazardous heavy metal pollutant present in the environment, and iron is an essential micronutrient with numerous cellular functions in normal physiology. However few studies have focused on the influence and interaction of lead and iron changes during plant growth. So the present study investigated the mechanism how lead and iron affected in upland rice (Oryza sativa L.) in order to clarify the relationship between iron and lead. The seeds of upland rice were supplied with iron (Fe), lead (Pb), and Fe and Pb together, respectively. Then the seed germination, ion absorption, gibberellins (GAs) and abscisic acid (ABA) metabolism and sugar utilization were determined. Lead treatment delayed upland rice seed germination, deactivated GA, inhibited GA signal transduction and increased ABA synthesis in the seed. In addition, the soluble sugar concentration in seeds was reduced alongside reduction in the activity levels of α-amylase (EC 3.2.1.1) and β-amylase (EC 3.2.1.2) during the earlier stages, but these increased in a time-dependent manner, reaching a stable level in response to lead-induced stress at 72 h. In contrast, iron alleviated the lead-induced changes in seed germination stage. Notably, the interaction between iron and lead increased GA signal transduction and inhibited ABA synthesis, whilst increasing starch hydrolysis and sugar consumption to augment rice seed germination. The results suggest that iron (such as in iron fertilizers) may be promising additives for agricultural use, improving plant germination, whilst simultaneously reducing the toxicity of lead in widely contaminated soils.

中文翻译：

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铁铅对旱稻种子萌发的影响及相互作用

铅是环境中存在的有害重金属污染物，而铁是一种必需的微量营养素，在正常生理机能中具有多种细胞功能。然而，很少有研究关注植物生长过程中铅和铁变化的影响和相互作用。为此，本研究对旱稻(Oryza sativa L.)中铅和铁的影响机制进行了研究，以阐明铁和铅之间的关系。旱稻种子分别供给铁（Fe）、铅（Pb）以及Fe和Pb。然后测定种子萌发、离子吸收、赤霉素（GAs）和脱落酸（ABA）代谢和糖的利用。铅处理延迟了旱稻种子萌发，使 GA 失活，抑制了 GA 信号转导并增加了种子中的 ABA 合成。此外，在早期阶段，种子中的可溶性糖浓度随着 α-淀粉酶 (EC 3.2.1.1) 和 β-淀粉酶 (EC 3.2.1.2) 活性水平的降低而降低，但这些以时间依赖性方式增加，达到在 72 小时时响应铅诱导的压力稳定水平。相比之下，铁减轻了种子萌发阶段铅引起的变化。值得注意的是，铁和铅之间的相互作用增加了 GA 信号转导并抑制了 ABA 合成，同时增加了淀粉水解和糖消耗以促进水稻种子发芽。结果表明，铁（如铁肥）可能是一种很有前途的农业添加剂，可促进植物发芽，同时降低广泛污染土壤中铅的毒性。