EFFECTS OF THE SODIUM AND CALCIUM CONCENTRATIONS ON THE IN-VITRO GROWTH OF ATRIPLEX-HALIMUS L PLANTLETS

The objective of this work is to analyse the sodium (Na+) and calcium (Ca++) importance in the in vitro morphogenesis of a halophile species the Atriplex halimus. The experiments have been made on plantlets coming from a seed population collected in a natural area (Algeria). Twenty medium, all different by their sodium chloride (NaCl) and calcium chloride (CaCl2) content, have been tested. For five Na+ concentrations, four [Na+]/[Ca++] ratios have been tested. The [Na+]/[Ca++] ratio has a significant effect on the studied criteria (stem length, longest root length and leaf number). The ratio equal to two is the one which gives the lowest values and the ratio equal to one (for the same [Na+] quantity and a double quantity of [Ca++]) gives the strongest ones. A new doubling of the (Ca++] (ratio equal to 0.5) induces a decrease of the values. These results are remarkable if we take into account the low cation concentrations used in the experiments. The morphogenetical events observed here will be explained when results about cation ratios inside the plant and the enzyme activity will have been obtained.