Placement of explants on the medium, either vertically or horizontally, resulted in different patterns of development. Horizontal orientation of D. pulcherrima var. buyssoniana not only produced more shoots but also induced multiple shoots, callus and
PLBs. This induction was performed by the appropriate ratio of auxin and cytokinin in explants. Fraxinus angustifolia and Quercus robur explants were found to have better induction by horizontal placement (Parez-Parron, 1994; Vieitez, 1994). On the other
hand, vertical orientation of Wrightia tomentosa was found better than horizontal orientation (Purohit,2004). The distinctive property auxin movement is known as basipetal transport (from tip to base). Vertically placed explants of D. pulcherrima var. buyssoniana might accumulate auxin at the base of base leaf segments, causing a high ratio of auxin: cytokinin, promoting plantlets, shoots and roots.