DEVELOPMENTAL POTENTIAL OF EXCISED PRIMORDIAL AND EXPANDING LEAVES OF COLEUS BLUMEI BENTH.

Coleus blumei Benth. primordial leaves 1 through 4 and expanding leaves 5 to 8 were isolated and cultured to examine the effects of auxin and kinetin on development. Without the plant growth regulators in the medium, expanding leaves 7 and 8 developed as leaves; younger leaf primordia did not develop. With 0.01 to 5.0 mg/1 IAA, 2–7% of the youngest pair of primordial leaves (1 and 2) developed as roots. Small leaf blade development occurred on IAA at 0.5 to 5.0 mg/1 with 10–12% of the explants, and shoots developed from 2% of the youngest primordia explants at 3 mg/1 IAA. With 2–28% of the second set of primordial leaves (3 and 4), a leaf with a root developed with 0.01 to 5.0 mg/1 IAA. At 3.0 mg/1 IAA, in addition to leaf formation, 2% of the explants formed a rosette of leaves and 1% formed a shoot. With the highest level of IAA (5 mg/1), 2% of the explants formed a root. Expanding leaves 5 through 8 developed mostly into leaves without petioles on IAA and kinetin. Plant development occurred from 2% of the youngest primordial leaves on 0.03 mg/1 kinetin; otherwise, these primordia on 0.003 to 2 mg/1 kinetin developed into abnormal leaves. Primordia 3 and 4 developed into normal appearing leaves at levels of kinetin between 0.03 and 2 mg/1. At lower levels the leaves were abnormal.