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Effects of long‐term salt stress on antioxidant defence systems, leaf water relations and chloroplast ultrastructure of potato plants
Author(s) -
FIDALGO FERNANDA,
SANTOS ARLETE,
SANTOS ISABEL,
SALEMA R
Publication year - 2004
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.2004.tb00374.x
Subject(s) - biology , ultrastructure , chloroplast , botany , water stress , antioxidant , salt (chemistry) , term (time) , biochemistry , gene , chemistry , physics , quantum mechanics
Summary The effect of long‐term (30 days) NaCl treatments (100 mM and 200 mM) on the activity of some antioxidant enzymes, level of antioxidant metabolites, water relations and chloroplast ultrastructure, was studied in potato (Solanum tuberosum cv. Désirée) leaves. Salt stress negatively affected relative water content, leaf stomatal conductance and transpiration rate. In treated plants, proline was enhanced, but there was a significant decrease in ascorbate and proteins. Total superoxide dismutase activity was increased. The isozyme patterns detected in native gels from salt‐irrigated plants were not changed although all the isoforms appeared more heavily stained due to higher activity. In contrast, at both levels of NaCl, catalase activity decreased and ascorbate peroxidase activity showed no significant change in comparison with an untreated control. At ultrastructural level, only thylakoid swelling and a decrease in the amount of grana stacking was observed in treated plants. The overall behaviour of the antioxidant enzymes suggests an increase of cellular H 2 O 2 that would contribute to the oxidative stress of potato plants, but which may be alleviated somewhat by the enhanced levels of proline.