INFLUENCE OF LIGHT-INTENSITY ON VEGETATIVE GROWTH OF PTILOTUS-EXALTATUS R BR

The influence of different intensities of light on vegetative growth o f Ptilotus exaltatus was Studied in growth chamber experiments with te mperature (28/24 degrees C day/night) and day length (12h). The stock plants were cultivated for 10 weeks at light intensities of 540, 360 a nd 180 mu mol m(-2) s(-1), respectively. Cuttings were harvested weekl y and inserted in rooting medium. After 12 harvest dates variations 1 and 2 (540 and 360 mu mol m(-2) s(-1)) resulted in significantly highe r yields and the proportion of cuttings with inflorescence inductions was higher compared to variation 3 (180 mu mol m(-2) s(-1)). High ligh t intensity (540 and 360 mu mol m(-2) s(-1)) resulted in inflorescence inductions of 66 and 48%, respectively, low light intensity (180 mu m ol m(-2) s(-1)) resulted only 11% in inflorescence induced cuttings. I n spite of high daytime temperature high light intensity forwarded the inflorescence induction. In spite of IBS-application none of the vari ations resulted in satisfying rooting. Cuttings of stockplants cultiva ted under high light intensity rooted worst. Due to the necessary cond itions for vegetative growth thigh daytime temperature and low intensi ty of light) and the not satisfying rooting the propagation of Ptilotu s exaltatus by cuttings remains difficult for ornamental plant growers .