Growth and Water Relations of Lotus Creticus Creticus Plants as Affected by Salinity

Abstract

Young plants of Lotus creticus creticus growing in a hydroponic culture were submitted to 0, 70 and 140 mM NaCl treatments for 28 d and the growth and ecophysiological characteristics of these plants have been studied. The growth of Lotus plants was not affected by salinity when applied for a short period (about 15 d); however, 140 mM NaCl induced a decrease in shoot RGR at the end of the treatment. The root growth was not decreased, even it was stimulated by 140 mM NaCl. The osmotic adjustment of Lotus plants at 70 and 140 mM NaCl maintained constant pressure potential, avoiding the visual wilting. For a similar leaf water potential, cuticular transpiration of salinized plants was lower than in control plants due to the salinity effect on the cuticle. Moreover, the presence of hairy leaves (60 and 160 trichomes per mm2 in young and adult leaves, respectively) allows keeping almost 81 % of sprayed water and absorbing the 9 % of the water retained, decreased the epidermal conductance to water vapour diffusion.