Experimental evidence for the autonomy of ray differentiation in Ficus sycomorus L.



Wounding or partial girdling leaving only a narrow cambial bridge resulted in changes in the xylem structure in stems and branches of Ficus sycomorus. Wounding inhihiitd the formation of fibre bands, induced tyiosis and differentiation of narrow vessels, and resulted in partially differentiated tissues. Partial girdling of mature trunks resulted in the formation of either a strip of traumatic xylem or a parenchymal strip in which all axial components failed to differentiate but the radial system was not affected and the rays continued to form. The differentiation of rays without an axial system is indicative of the autonomy of the radial signal system that participates in the regulation of ray formation.