MORPHOLOGICAL-CHARACTERISTICS OF IMPATIENS-FLANAGANIAE HEMSL. GROWN UNDER DIFFERENT LIGHT CONDITIONS

Impatiens flanaganiae Hemsl. is a rare plant which preferentially grow s in shady conditions and exhibits strong apical dominance. The morpho logical plasticity of I. flanaganiae In response to light intensity in laboratory conditions was investigated, Unbranched plantlets of I. fl anaganiae propagated from tubers were exposed to three light regimes: 30, 55 and 280 microeinsteins m(-2) sec(-1) for a period of seven week s. Plants grown under lower light intensity (30-55 microeinsteins m(-2 ) sec(-1)) developed long unbranched stems about 65 cm in length and f ewer leaves with a large leaf area. In contrast, reduced stem extensio n (up to 35 cm) and multiple lateral branches were observed in plants exposed to higher light intensity (280 microeinsteins m(-2) sec(-1)). A significant increase (at 5% level) in the number of leaves in plants from this variant was found to be inversely proportional to the leaf area, Extended exposure of the plants to higher light intensities seem s to be stressful and resulted in abnormal biochemical and morphologic al changes such as chlorosis, necrosis and curling of the leaves. The strong increased premium on lateral growth of I. flanaganiae, induced by light intensity of 280 microeinsteins m(-2) sec(-1) resulted in a g reater number of lateral branches which were found to be suitable for its rapid acid more efficient propagation in vivo by cuttings or in vi tro by shoot tip culture.