Effects of temperature, water stress and saline stress on seeds germination of Tetraclinis articulata (Vahl) Masters in Saïda, Algeria

Abstract

Tetraclinis articulata (Vahl) Masters is a coniferous tree, endemic to North Africa and considered as an endangered species in Algeria despite having ecological, socio-economic and environmental interests. Ecologists and foresters today insist on the eminent place that this forest essence plays in the structuring of the vegetal landscapes of the Maghreb, but also on its forest and economic value (Terras et al., 2008). The objective of this work is mainly to define the main saline and water concentrations promoting the multiplication and the regeneration of this essence since the process of its degradation is gradually accentuated. The effect of incubation temperature and the impact of saline and water stresses on seed germination were studied. The salinity treatments used were 0, 25, 50,100, 150 mm/L of NaCl, while water deficits of 0, -0.5, -1, -1.5, -2 and -3 Bars were induced using PEG-6000. The maximum germination percentage (85%) was obtained under control condi-tions. A negative correlation was obtained between NaCl concentration and seed germination, while at the concentration of 150 mm/L germination was 5%, suggesting that T. articulata is moderately salt tolerant at the germina-tion stage. The results of water stress impact test indicate that T. articulata seeds are quite tolerant to water stress, with a germination capacity of 40% when the seeds are exposed to a PEG solution of -2 Bars, this is a rather remarkable low value compared to other Mediterranean tree species from arid and semi-arid areas.