CONTRIBUTION TO STUDY OF ACACIA TORTILIS SUBSP RADDIANA SEED GERMINATION, AND GROWTH SEEDLING UNDER DIFFERENT OSMOTIC AND DROUGHT CONSTRAINTS

摘要

Acacia raddiana or Acacia tortilis (Forsk) Hyane subsp. raddiana (Savi) Bernan, (Fabaceae) is characterized by a great ecological plasticity. It is largely used by the local populations as medicinal plants, fodder, wood energy, coal because it high calorific value. This plant thus plays a big role in rural economy because it is also appreciated in craft industry and for the clothes, tools and kitchen utensil manufacture. The study of the intensity osmotic stress effect on the germination of Acacia raddiana seeds reveals that there is a very strong negative correlation between the increase of the concentration of PEG and the germination rate (r = -0.9251). The fact remains that in spite of very small negative potential, Acacia raddiana seeds are very resistant since it coming to sprout at potential matching -6.0 MPa. In otherwise, the foliar RWC of seedling remained stable during the 25 days of treatment at about 81.61 ?± 7.61% (control) and dropped from 17th to 25th day at 32% (stressed). The growth was also affected by stress. Thus, both leaves number and stem height is reduced in stressed plants compared to controls.