Effect of Metal Toxicity on Plant Growth and Metabolism: I. Zinc

Abstract

Zinc toxicity and problems with regard to tolerance and ecological significance are briefly discussed. Differential tolerance of plant genotypes exposed to zinc toxicity is a more promising approach to enrich our understanding of zinc tolerance in plants. Knowledge concerning the physiology and biochemistry with regard to phytotoxicity, uptake and transport of zinc and tolerance and its characterization are also discussed. The cytotoxic effects of zinc on plants are elucidated. The major change was seen in the nucleus of the root tip cells due to zinc toxicity. The chromatin material was highly condensed and some of the cortical cells showed disruption and dilation of nuclear membrane in presence of 7.5 mM zinc. The cytoplasm became structureless, disintegration of cell organelles and the development of vacuoles were also observed. The number of nucleoli also increased in response to zinc resulting in the synthesis of new protein involved in heavy metal tolerance. This review may help in interdisciplinary studies to assess the ecological significance of metal stress. phytotoxicity / tolerance / transport / uptake / accumulation / zinc Résumé-Effet de la toxicité des métaux sur la croissance et le métabolisme des plantes : I. Zinc. La toxicité du zinc et les problèmes de tolérance ou de conséquence écologique liés sont brièvement discutés. L'approche en terme de tolérance différentielle des génotypes de plantes exposées à la toxicité du zinc est prometteuse pour l'enrichissement de notre compréhension de la tolérance des plantes au zinc. Les connaissances de la physiologie et la biochimie face à la phytotoxicité, à l'absorption et au transport du zinc, ainsi que la tolérance et sa caractérisation sont aussi discutées dans ce papier. Les effets cytotoxiques du zinc sur les plantes sont maintenant élucidés. La modification majeure concerne le noyau des cellules de l'extrémité des racines. La chromatine est fortement condensée et certaines des cellules corticales montrent la rupture et la dilatation de leur membrane nucléaire en présence de 7.5 mM de zinc. De plus, le cytoplasme perd sa structure, la désintégration d'organites et le développement de vacuoles sont aussi observés. Enfin, le nombre de nucléoles augmente en réponse au zinc. Ils résultent de la synthèse d'une nouvelle protéine impliquée dans la tolérance aux métaux lourds. Cette synthèse bibliographique pourra aider les études interdisciplinaires à évaluer les conséquences écologiques des stress dus aux métaux. phytotoxicité / tolérance / transport / absorption / accumulation / zinc

Salicylic acid accumulation as a result of Cu, Zn, Cd and Pb interactions in common reed (Phragmites australis) growing in natural ecosystems

“…Despite its crucial function, elevated concentrations of Zn (above the level of 100-300 lg g -1 DW) usually cause severe toxic effects (Rout and Das 2009). Although the mobility rate of Zn in the environment is rather low, higher concentrations of the element can be noted in areas close to incineration facilities, smelters, mines and electroplating industry as a consequence of dry and wet deposition of airborne Zn-rich particles.…”

“…Although the mobility rate of Zn in the environment is rather low, higher concentrations of the element can be noted in areas close to incineration facilities, smelters, mines and electroplating industry as a consequence of dry and wet deposition of airborne Zn-rich particles. Intense urbanization, domestic waste water discharge, building industry and vehicles are also significant sources of Zn (Rout and Das 2009). In our study, Zn concentration was the highest among the four metals analyzed (37.5 and 31.5 mg kg -1 DW, in rhizomes and leaves, respectively), but the peak values did not reach the phytotoxicity threshold (Fig.…”

The Application of Homogenate and Filtrate from Baltic Seaweeds in Seedling Growth Tests

“…Although zinc is an essential nutrient for plant growth, elevated concentrations can result in growth inhibition and toxicity symptoms [26].…”

“…Additionally, the obtained bio-products were enriched with Zn(II) ions in order to examine their ability to complex metal ions. Zinc was chosen as an example of metal ions, because it plays a crucial role in plant growth and metabolism [26]. This issue has not been discussed in details in the available literature yet.…”

A Novel Sensitive Bulk Optode Based on 5-Br Salophen as an Ionophore for Determination of Zinc Ion in Real Samples

“…Moreover, the free zinc ion in solution is toxic to plants and aquatic organisms. 3,4 Therefore, due to the pressing need for sensitive zinc determination in biological and environmental samples, particularly water samples, various analytical techniques have been proposed for the determination of zinc. Spectrophotometry, 5 atomic absorption spectroscopy (AAS), 6 inductively coupled plasma atomic emission spectrometry (ICP-AES), 7 solidphase extraction, 8 liquid-liquid extraction, 9 dispersive liquidliquid extraction, 10 ion-imprinted polymer nanoparticle, 11 nuclear magnetic resonance (NMR) molecular sensor, 12 and stripping potentiometry 13,14 are among the most used techniques.…”