Gardenia is an ornamental shrub or small tree that has thick dark evergreen leaves and fragrant flowers of white colour. It is used as a garden plant in the mild climate as well as a flowering potted plant. Many studies have been taken to propagate gardenia in vitro and to reduce the time necessary for the introduction of new cultivars. The present study investigated the effect of different light qualities (white, blue, yellow, red) on shoot and root development and growth of Gardenia jasminoides Ellis. Shoot tips were obtained from aseptic in vitro cultures and explants were cultured on modified Murashige and Skoog medium containing BA at 5 or 25 µM as well as on medium without growth regulators. The experiment lasted 6 weeks and was repeated twice. The promoting effect of yellow light on the length of the main shoot growing on control medium was noted. There was no significant effect of different light qualities on the number of axillary shoots obtained from tip shoots cultured on growth regulator-free medium. Yellow light increased the number of axillary shoots from explants cultivated on medium containing 25 µM BA and it promoted shoot elongation most strongly on medium with the addition of 5 µM BA. Red and yellow light increased the number of roots on control medium, whereas yellow light significantly promoted root elongation growth. However, yellow and white light had the most positive effect on the average fresh weight of roots.

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