PLANT-RESPONSES TO WATER-STRESS - CHANGES IN GROWTH, DRY-MATTER PRODUCTION, STOMATAL FREQUENCY AND LEAF ANATOMY

The responses of seedlings of three fast growing tree species, Eucalyp tus hybrid (E. camaldulensis x E. teriticornis), Casuarina equisetifol ia and Melia azedarach, to different levels of soil moisture in contro lled glasshouse conditions were compared. The survival percentage, hei ght of plants, number of leaves per plant, number of branches, fresh m ass and dry mass of roots, stems, branches and leaves decreased in the three species with increasing water stress. Stomatal frequency and le ngth of stomata in Eucalyptus and Melia also decreased with increasing water stress. However, no significant difference was obtained in the width of stomata and the ratio of number of open stomata to total numb er of stomata per unit area. The leaf thickness decreased, but the thi ckness of palisade parenchyma increased with increasing water stress i n Eucalyptus hybrid and Casuarina. Leaf thickness of Melia did not sho w any significant variation due to water stress.