The effect of drought on gas exchange and water potential in leaves of seven Mediterranean woody species

The water relations and gas exchange parameters of Arbutus unedo, Cistus monspeliensis, Erica arborea, Myrtus communis, Phillyrea latifolia, Pistacia lentiscus, and Quercus ilex growing in the shrubland vegetation at the Parco Naturale della Maremma (Italy), were studied over two consecutive years. At high leaf water potentials, photosynthetic rates and stomatal conductance were relatively low in all species but C. monspeliensis. Stomatal conductance remained relatively high in C. monspeliensis leaves as soil moisture was depleted, whereas A. unedo, E. arborea, M. communis, and P. lentiscus were more conservative in water use. P. latifolia and Q. ilex showed a drought-tolerant behaviour.