FIGURE 2.

Gas exchange, photosynthesis measurements and water use efficiency under field conditions. Transpiration (E) (A), Net photosynthesis (Pn) (B), Maximal efficiency of PSII (C) and instantaneous water use efficiency (WUE_inst) (D) of drought-sensitive and drought-tolerant seed sources under control site(white bars; La Hunde site, considered the core habitat) and the dry site (black bars; La Granja d’Escarp considered the marginal dry habitat for this species). The letters above the bars marks the significant difference among the drought-stressed seed sources following the post hoc Duncan’s test with n = 5. Scale bars are mean +SE.