Evidence suggests that heavy-metal tolerance can be induced in plants following pre-treatment with non-toxic metal concentrations, but the results are still controversial. In the present study, tobacco plants were exposed to increasing Zn(2+) concentrations (up to 250 and/or 500 μM ZnSO4) with or without a 1-week acclimation period with 30 μM ZnSO4. Elevated Zn(2+) was highly toxic for plants, and after 3 weeks of treatments there was a marked (≥50%) decline in plant growth in non-acclimated plants. Plant acclimation, on the other hand, increased plant dry mass and leaf area up to 1.6-fold compared with non-acclimated ones. In non-acclimated plants, the addition of 250 μM ZnSO4 led to transient membrane depolarization and stomatal closure within 24h from the addition of the stress; by contrast, the acclimation process was associated with an improved stomatal regulation and a superior ability to maintain a negative root membrane potential, with values on average 37% more negative compared with non-acclimated plants. The different response at the plasma-membrane level between acclimated and non-acclimated plants was associated with an enhanced vacuolar Zn(2+) sequestration and up to 2-fold higher expression of the tobacco orthologue of the Arabidopsis thaliana MTP1 gene. Thus, the acclimation process elicited specific detoxification mechanisms in roots that enhanced Zn(2+) compartmentalization in vacuoles, thereby improving root membrane functionality and stomatal regulation in leaves following elevated Zn(2+) stress.

Zn2+-induced changes at the root level account for the increased tolerance of acclimated tobacco plants / N. Bazihizina;C. Taiti;L. Marti;A. Rodrigo-Moreno;F. Spinelli;C. Giordano;S. Caparrotta;M. Gori;E. Azzarello;S. Mancuso. - In: JOURNAL OF EXPERIMENTAL BOTANY. - ISSN 0022-0957. - STAMPA. - 65:(2014), pp. 4931-4942. [10.1093/jxb/eru251]

Zn2+-induced changes at the root level account for the increased tolerance of acclimated tobacco plants

BAZIHIZINA, NADIA;TAITI, COSIMO;MARTI, LUCIA;SPINELLI, FRANCESCO;CAPARROTTA, STEFANIA;GORI, MASSIMO;AZZARELLO, ELISA;MANCUSO, STEFANO
2014

Abstract

Evidence suggests that heavy-metal tolerance can be induced in plants following pre-treatment with non-toxic metal concentrations, but the results are still controversial. In the present study, tobacco plants were exposed to increasing Zn(2+) concentrations (up to 250 and/or 500 μM ZnSO4) with or without a 1-week acclimation period with 30 μM ZnSO4. Elevated Zn(2+) was highly toxic for plants, and after 3 weeks of treatments there was a marked (≥50%) decline in plant growth in non-acclimated plants. Plant acclimation, on the other hand, increased plant dry mass and leaf area up to 1.6-fold compared with non-acclimated ones. In non-acclimated plants, the addition of 250 μM ZnSO4 led to transient membrane depolarization and stomatal closure within 24h from the addition of the stress; by contrast, the acclimation process was associated with an improved stomatal regulation and a superior ability to maintain a negative root membrane potential, with values on average 37% more negative compared with non-acclimated plants. The different response at the plasma-membrane level between acclimated and non-acclimated plants was associated with an enhanced vacuolar Zn(2+) sequestration and up to 2-fold higher expression of the tobacco orthologue of the Arabidopsis thaliana MTP1 gene. Thus, the acclimation process elicited specific detoxification mechanisms in roots that enhanced Zn(2+) compartmentalization in vacuoles, thereby improving root membrane functionality and stomatal regulation in leaves following elevated Zn(2+) stress.
2014
65
4931
4942
N. Bazihizina;C. Taiti;L. Marti;A. Rodrigo-Moreno;F. Spinelli;C. Giordano;S. Caparrotta;M. Gori;E. Azzarello;S. Mancuso
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/873730
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