Effet Du Stress Salin Sur Quelques Paramètres Phoenologiques (biométrie, Anatomie) Et Nutritionnels De L’atriplex En Vue D’une Valorisation Agronomique

Résumé: The impact of salinity, applied for a week with combined salt NaCl + CaCl 2 (400 and 600 meq) and seawater (50% and 100%) was studied in two species of young seedlings of Atriplex halimus L. and Atriplex canescens (Pursh) Nutt. The biometric component, anatomical and nutritional were selected as likely indices of tolerance to salt stress. We compared changes between control plants and those under stress. Thus, at the root level, by measuring the volume of languor and root anatomy of the stem and root as well as the analysis of the levels of sodium, potassium and calcium in leaves stems and roots. The results show a variation in the action of salt stress on species, organ, nature and concentration of salt treatment. Root growth in length and volume is not affected by salt stress. The anatomical structure of roots and stems treated showed no significant abnormalities. The only changes in stems in both species of Atriplex are marked by a decrease in the size of parenchymal cells, as well as the diameter of xylem vessels and increasing their number, under the action of combined salts (600 meq of NaCl + CaCl2) and pure sea water. At the anatomical level of root’s sections Atriplex halimus watered with combined salts (600 meq) and pure seawater, the only observed change is the reduction of the diameter of xylem vessels and the increase of their number. Furthermore, salinity has caused some changes in levels of mineral nutrition cations. Thus, the accumulation of sodium is highly significant compared with controls in plant leaves of Atriplex halimus treated 400 meq NaCl + CaCl2 and those of Atriplex canescens stressed with 50% seawater, the accumulation of this cation is not significant. On the K+ , both species react differently, the K+ content decreased in leaves of Atriplex halimus when the intensity of stress increases, the reverse was observed in leaves of Atriplex canescens. Regarding calcium, the effect of stress is highly significant on the accumulation of Ca++ in the leaves of both species under salt treatment of NaCl + CaCl2 to 600 meq, and in stems of Atriplex halimus in the same treatment to 400 meq and 600 meq.

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