Morphological and physiological comparisons of plantlets in vitro : Responses to salinity

Different clones of Albizia lebbeck were cultured in vitro on Murashige and Skoog (1962) Gelrite medium containing 30 g 1 - sucrose. After culturing in vitro for 42 days, the medium was added 5 ml sodium chloride (NaCI) at four level concentrations (0, 100, 200 or 300 g 1 -1 ) at 30 ± 2°C air temperature. The cultures were grown under two levels of relative humidity (90-100 or 50-60%). Morphological and physiological changes were observed for 14 days. High concentration of NaCI decreased the leaf area, shoot dry weight, root dry weight, and chlorophyll content under either the high or low relative humidity. The survival percentage of plantlets in vitro was twice as high from the high relative humidity compared with the low relative humidity. The survival percentage was lowest in the treatment with 300 g 1 -1 NaCI and low relative humidity.