ECOPHYSIOLOGY OF CUTICULAR TRANSPIRATION - COMPARATIVE INVESTIGATION OF CUTICULAR WATER PERMEABILITY OF PLANT-SPECIES FROM DIFFERENT HABITATS

Water permeabilities of astomatous, isolated cuticular membranes (CM) of 24 different plants species were measured. Permeances varied from 1 .7x10(-11) m . s(-1) (Vanilla planifolia leaf) up to 2.1x10(-9) m . s( -1) (Malus cf. domestica fruit) among different plant species, thus co vering a range of over 2 orders of magnitude. Ranking of species accor ding to permeances resulted in four distinct groups. The first group, of species with the lowest cuticular transpiration rates, included eve rgreen species growing in warm dry tropical climates (e.g. Vanilla pla nifolia and Monstera deliciosa leaves). The second class, with slightl y higher water permeabilities, included evergreen species with typical scleromorphic leaf properties, adapted to a typical mediterranean typ e of climate with a dry period during he year (e.g. Citrus limon and O lea European leaves). The third group of species, where the highest le af cuticular transpiration rates were observed, included deciduous spe cies normally growing in a temperate climate (e.g. Juglans regia and F orsythia suspensa leaves). Fruit cuticular membranes (CM) made up the fourth group (e.g. Capsicum annuum and Malus cf. domestica fruits), wi th even higher permeances than leaves of species from group 3. Thus, i t appears that the plant species investigated show ecophysiological ad aptations to the climatic demands of their natural habitats in cuticul ar water permeability.