Heavy metal-induced oxidative stress on seed germination and seedling development: a critical review

Mihiri Seneviratne, Nishanta Rajakaruna, Muhammad Rizwan, H. M.S.P. Madawala, Yong Sik Ok, Meththika Vithanage

Research output: Contribution to journalArticlepeer-review

215 Citations (Scopus)

Abstract

Heavy metal contamination in soils can influence plants and animals, often leading to toxicosis. Heavy metals can impact various biochemical processes in plants, including enzyme and antioxidant production, protein mobilization and photosynthesis. Hydrolyzing enzymes play a major role in seed germination. Enzymes such as acid phosphatases, proteases and α-amylases are known to facilitate both seed germination and seedling growth via mobilizing nutrients in the endosperm. In the presence of heavy metals, starch is immobilized and nutrient sources become limited. Moreover, a reduction in proteolytic enzyme activity and an increase in protein and amino acid content can be observed under heavy metal stress. Proline, is an amino acid which is essential for cellular metabolism. Numerous studies have shown an increase in proline content under oxidative stress in higher plants. Furthermore, heat shock protein production has also been observed under heavy metal stress. The chloroplast small heat shock proteins (Hsp) reduce photosynthesis damage, rather than repair or help to recover from heavy metal-induced damage. Heavy metals are destructive substances for photosynthesis. They are involved in destabilizing enzymes, oxidizing photosystem II (PS II) and disrupting the electron transport chain and mineral metabolism. Although the physiological effects of Cd have been investigated thoroughly, other metals such as As, Cr, Hg, Cu and Pb have received relatively little attention. Among agricultural plants, rice has been studied extensively; additional studies are needed to characterize toxicities of different heavy metals on other crops. This review summarizes the current state of our understanding of the effects of heavy metal stress on seed germination and seedling development and highlights informational gaps and areas for future research.

Original languageEnglish
Pages (from-to)1-19
Number of pages19
JournalEnvironmental Geochemistry and Health
DOIs
Publication statusAccepted/In press - 2017 Jul 12
Externally publishedYes

Keywords

  • Antioxidant system
  • Chlorophyll
  • Heavy metal stress
  • Proline
  • Protein degradation
  • Starch mobilization

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Water Science and Technology
  • General Environmental Science
  • Geochemistry and Petrology

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