Variabilité des caractères morphologiques des Populations naturelles d’Atriplex subsp. halimus et subsp. Schweinfurthii Cas Mostaganem Oran

Abstract

The Atriplex halimus is a polymorphic plant, morphological polymorphism appears to be a characteristic which manifests itself in the size and shape of leaves, fruiting valves, seeds. The results obtained in this work allowed us to distinguish between the two subspecies Atriplex halimus sub sp halimus from Kharrouba Mostaganem and Atriplex halimus sub sp schweinfurhii from the Es Sénia Oran site. Both populations are found in a different climatic cotext where the annual mean rainfall of Mostaganem's Kharrouba site is observed to vary from one year to another with a pronounced drought. 2017 with a rainfall rate of 325.38 mm. Annual averages of maximum temperatures are quite high, a very high rate exceeding 70%. The wind winds in April with a maximum speed of (3.4 m/s). The study of the average annual rainfall of the Oran site highlights a rainfall that exceeds 400 mm. For a period of fifteen years the maximum temperatures are those of July and August with 30.96 and 32.98 ° C, a maximum relative humidity was recorded for the month of January 79%. and February a rate of 77%. average wind speed is between 1.2 and 1.8 m/s for most of the years studied. The Kharrouba Mostaganem site and the Es Sénia Oran site are located in a semi-arid climate. Mostaganem station was located in the semi-arid semi-arid level with warm winter, with a Q 2 that was 40.3 with a temperate winter but still in the semi-arid. The Oran region also saw a Q 2 of 39.73 it is on the floor. The physiogeneity and heterogeneity of the populations of Atriplex halimus The population of Atriplex halimus site kharrouba with the size of the tufts is between 1.23 m and 2.47 m vari diameter between 0.97 m and 2.39 m. The population of Atriplex halimus of the site Es Sénia, whose size of the tufts is between 1.42 m and 2.39 m, the diameter varies between 0.99 and 19.50 m. The observation of the morphology of Atriplex halimus. many forms that differ from one plot to another. The tufts far from the sea are less spread with few ramifications (less developed). The waves exposed to the wind and the marine embrun are well spread with high height and diameter growth (well developed). On the other hand, the tufts of the Es Sénia Oran site note that the tufts are well developed and very branched in diameter. The tufts form a dense thicker, very branched basal branching with a high number of branches and branching density. The people of the Atriplex population halimus have shown the highest leaf ratio is 1.72, leaves are longer and less broad, with several forms including form, Rhomboïdale, Ob ovoid, Orbiculaire, Lancéolé, oval etc… The leaves are quite dissimilar. The population of Atriplex halimus sub sp schweinfurhii showed the highest leaf ratio of 2.08, leaves were longer and less broad. Most leaves have a distinct form that is the laneroid form where leaves are small, and other forms such as Eccliptic, Ovale, Rhomboïdale have been noticed. Dry matter analysis results show a dry matter rate of 38.73% of Atriplex, subsp. Schweinfurthii of the Es Sénia site (Oran) This rate is significantly higher than the Atriplex dry matter rate, subsp halimus of 34, 20%. Tetraploid karyotypes (2 n = 4 x = 36) generally corresponded to subsp phenotype. Schweinfurthii. The Atriplex, subsp halimus, was diploid (2 n = 2 x = 18).