Physiological Response to Water Stress in Pistacia atlantica Desf. Seedlings from Two Contrasting Bioclimates in Algeria

This study aims to assess the response of Pistacia atlantica Desf. seedlings to water stress under laboratory conditions. A total of 80 seedlings (11 months old) of the same species from two contrasting sites in Algeria: M.d.a (sub-humid with 5 dry months) and Bechar (arid with 12 dry months) were subjected to water stress for 15 and 30 days. Their physiological response was assessed by measurements of leaf water potential, leaf pigment content, chlorophyll fluorescence, and gas exchange. The results showed a significant (p < .05) effect of water stress on all measured parameters for both provenances compared to the control. Leaf water potential (Ψw), pigment content, maximum quantum yield of photosystem II reaction centers (Fv/Fm), effective quantum efficiency of photosystem II (ΦPSII), photochemical quenching, stomatal conductance (gs), net photosynthetic rate (A), transpiration rate (E), and mesophyll efficiency (A/E) decreased in both provenances as drought stress developed, especially in M.d.a compared to the control. In contrast, the carotenoid/ total chlorophyll ratio, the water use efficiency (WUE = A/E), and the non-photochemical quenching increased significantly in both provenances, especially in Bechar compared to the control. Disturbances in photosynthetic activity may be due to stomatal and non-stomatal limitations, depending on the severity of water stress. The provenance from the arid site showed a stronger photosynthetic performance under water stress compared to that from the sub-humid site. This suggests the existence of adapted ecotypes and that the Bechar plant material is more suitable for reforestation programs in arid areas.

Cite this article as: Ait Said, S., Chikhaoui, Z., Dib, T., Amirat, Y., Krouchi, F., Rabhi, K., & Labchri-izri, D. (2026). Physiological response to water stress in Pistacia atlantica Desf. seedlings from two contrasting bioclimates in Algeria. Forestist, 75, 0100, doi:10.5152/forestist.2026.24100.