ISSN:
0931-1890
Keywords:
Key words Eucalyptus citriodora
;
Salinity
;
Malate
;
NAD(P) malic enzymes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Three-month-old plants of Eucalyptus citriodora were grown in a greenhouse in a culture medium adjusted either to 50 or 100 mM NaCl. Sodium was rapidly absorbed by the plants and as early as 3 weeks after treatment, an increased Na+ level was observed in shoots of 50 mM NaCl plants. At this stage of treatment, the growth of plants was not reduced but the malate metabolism was modified. The malate content decreased in leaves while the specific activities of NAD and NADP-malic enzymes increased. The stimulation in enzyme activity was more pronounced for NADP-malic enzyme but for both enzymes, enzyme activity diminished as early as 5 weeks after treatment. The immunological study showed that the higher activity of NAD-malic enzyme was linked to an increase in the protein amount. By contrast, a more active form of the NADP-malic enzyme mainly accounted for the higher activity of this enzyme without involving modification in the electrophoretic mobility of the protein. The 100 mM NaCl treatment also induced changes in the malic enzyme behaviour, the magnitude of the response however being less than for the 50 mM treatment. These results are discussed, mainly considering the role of these enzymes in the reducing power of the leaf cell.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/PL00009699
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