Physiological adaptation and gene expression analysis of Casuarina equisetifolia under salt stress
Casuarina equisetifolia is widely planted in coastal areas of tropical and subtropical regions as windbreaks or to stabilize dunes against wind erosion due to its high salt tolerance and nitrogen-fixing ability. To investigate the mechanisms responsible for its salt tolerance, we examined growth, mi...
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Veröffentlicht in: | Biologia plantarum 2018-09, Vol.62 (3), p.489-500 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Casuarina equisetifolia
is widely planted in coastal areas of tropical and subtropical regions as windbreaks or to stabilize dunes against wind erosion due to its high salt tolerance and nitrogen-fixing ability. To investigate the mechanisms responsible for its salt tolerance, we examined growth, mineral composition, expression of genes for sodium (Na
+
) and potassium (K
+
) transport proteins, and antioxidant responses under NaCl treatments. Increasing NaCl concentrations inhibited lateral root elongation and decreased plant height, length of internodes, and numbers of branches and twigs. The Na
+
content significantly increased whereas the K
+
content significantly decreased in both shoots and roots with increasing external NaCl concentration, resulting in a significant increase in Na
+
/K
+
ratio. Most of the Na
+
/H
+
antiporter genes (
NHXs
) were obviously upregulated in roots after 24 and 168 h of salt stress, and
NHX7
was especially induced after 168 h. Almost all salt overly sensitive (
SOS
) genes were induced after 168-h treatment. Additionally, activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly changed in shoots and roots under salt stress. Hence, we conclude that salinity tolerance of
C. equisetifolia
mainly relied on sequestering excess Na
+
into vacuoles and on induced expression of
NHX
and
SOS
genes in roots and thus the maintenance of sufficient K
+
content in shoots. |
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ISSN: | 0006-3134 1573-8264 1573-8264 |
DOI: | 10.1007/s10535-018-0799-y |