Rooting response of etiolated stem segments of Populus nigra to antimetabolites in relation to indole-3-acetic acid and glucose

Abstract

2.5 cm long etiolated stem segments of Populus nigra did not root at all in water or in IAA alone, but rooted in glucose + IAA. 5-Fluorodeoxyuridine (FUDR), 5-Fluorouracil (FU). actinomycin-D and cycloheximide all inhibited rooting, the inhibitory effect of each increasing with concentration and being more marked in glucose than in glucose + IAA. The inhibitory effect also decreased with the delay in the application of cycloheximide. The DNA, RNA and protein contents of segments grown in IAA + glucose where rooting occurred were higher than in water or in IAA + glucose + cycloheximide/or + aetinomycin-D where rooting did not occur. Auxin in the presence of adequate amount of carbon nutrition increases the fresh production of protein and that the magnitude of rooting is determined by the size of protein pool that is available in tho tissue at the time of root initiation.