Some Investigations of Auxin Effects on Rooting of Stem Cuttings of Forest Plants

This paper deals with the effect of 10 and 100 mg/l each of IAA, IBA, 2,4-D and NAA on seasonal changes in the ischolar_maining response of stem cuttings of forest plants. Anatomical structure of stem and seasonal changes in the mobilization of reserve food materials in a few cases were also studied. Experiment 1 deals with ischolar_maining trials on 102 broad-leaved species at 3-month intervals; experiment 2 on 9 species at 1-month intervals and experiment 3 with stem anatomy of some representative species. It was found that ischolar_maining occurred in 49 species only; on 26 without and 23 with auxin application. Of these 6 ischolar_mained throughout the year; 7 in 3 out of 4 plantings; 12 in two and 21 in one planting only. Stem cuttings of 53 species did not ischolar_main at all. The easy-ischolar_maining species possessed multi-seriate vascular rays opening directly in the cortical region, while shy-ischolar_maining ones possessed a continuous ring of sclerenchyma surrounding the vascular bundles and which probably acted as a barrier to the penetration of water and emergence of ischolar_mains. Stem cuttings of Populus nigra, Hibiscus rosa-sinensis and Ficus infutoria exhibited seasonal changes in ischolar_maining response closely corresponding with changes in starch content; low ischolar_maining corresponding with high and high ischolar_maining with low content of starch. Auxin effects on ischolar_maining are considered to be mediated through their effect on mobilization of starch caused by enhanced activity of hydrolyzing enzymes and is determined by the morpho-physiological status of the branches that govern the production of endogenous auxin.