Stomatal conductance and leaf water potential at around noon, pre-dawn leaf
water potential, pressure–volume parameters, and leaf structural
characteristics including leaf thickness, leaf dry mass per unit area and
turgid leaf water content per unit area were compared between a coastal shrub
species, Eurya emarginata (Thunb.) Makino and an inland
shrub species, E. japonica Thunb. The pre-dawn leaf
water potential was only slightly lower in E. emarginata
than in E. japonica, and the environmental conditions
such as the photosynthetic photon flux density and the vapour pressure deficit
did not differ obviously between the two habitats. No apparent differences
were observed in the pressure–volume parameters between the two species.
On the other hand, E. emarginata had much higher
stomatal conductance and significantly thicker leaves with higher turgid leaf
water content per unit area than E. japonica. The
thicker leaf with higher water content on an area basis in
E. emarginata maintains adequate leaf turgor pressure
against a higher rate of transpiration.