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

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 Zn2+ concentrations (up to 250 and/or 500 ?M ZnSO4) with or without a 1-week acclimation period with 30 ?M ZnSO4. Elevated Zn2+ 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 ?M 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 Zn2+ 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 Zn2+ compartmentalization in vacuoles, thereby improving root membrane functionality and stomatal regulation in leaves following elevated Zn2+ stress.

SUBMITTER: Bazihizina N

PROVIDER: S-EPMC4144771 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature

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

Bazihizina Nadia N Taiti Cosimo C Marti Lucia L Rodrigo-Moreno Ana A Spinelli Francesco F Giordano Cristiana C Caparrotta Stefania S Gori Massimo M Azzarello Elisa E Mancuso Stefano S

Journal of experimental botany 20140613 17

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 Zn2+ concentrations (up to 250 and/or 500 μM ZnSO4) with or without a 1-week acclimation period with 30 μM ZnSO4. Elevated Zn2+ was highly toxic for plants, and after 3 weeks of treatments there was a marked (≥50%) decline in plant growth in non-acclimated plants. ...[more]

PMID: 24928985

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Dataset Information

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

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

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