Resistance to water stress in seedlings of eight European provenances of Pinus halepensis Mill.

In this study, pressure/volume curves were performed on 24-week-old seedlings of eight European provenances of Pìnus halepensis Mill. subsp. halepensis after one week of water stress (-0.033, -0.4, -0.8, -1.2, -1.6 MPa). P. halepensis showed osmotic adjustments as a response to water stress, although the response varied between the provenances. Apoplastic water remained relatively Constant. The elasticity module did not differ significantly. Water deficit at incipient plasmolysis and water content decreased as the stress increased. Water potential was markedly negative, even in seedlings not subjected to stress. The provenances from less xeric sites behaved similarly to species from non-arid sites, while those from more xeric sites displayed the strategy typical of drought-tolerant species. The impact on all provenances of one week of low-intensity water stress (-0.4 MPa) was slight.