SEASONAL CHANGES IN ROOTING RESPONSE OF HARDWOOD CUTTINGS OF TEAK (TECTONA GRANDIS LINN. F.) IN RELATION TO DRIFT OF TOTAL SOLUBLE SUGAR, STARCH AND TOTAL NITROGEN

摘要

The rooting response in hardwood cuttings of Tectona grandis Linn. f. (Teak) as influenced by the month of planting (season), position of branch in the crown and three concentrations of NAA was examined under open environmental condition prevailing atNew Forest Campus, Forest Research Institute, Dehra Dun, India. The rooting response of stem cuttings of mature teak trees (40-years-old) changed with season. The response was the best in the rainy season (July/August) while it was very poor during falland winter i.e., October to February. Seasonal variations in the rooting response of cuttings are related to the changes in morpho-physiological status of the donor plants. The findings also indicate a positive relationship of high carbohydrates (totalsoluble sugar and starch) and total nitrogen (C/N) ratio with more profuse rooting of teak cuttings. However, total soluble sugar levels were high and total nitrogen low in July-August when the rooting was more profuse; C/N ratio was low from September onwards and cuttings rooted very poorly. The effect of NAA on rooting teak stem cuttings varied with season. NAA caused maximum promotion of rooting in the summer and rainy season while, its effect was much less during the autumn and winter season. The position of the branch from which the cuttings were taken had a significant effect on their rooting and sprouting behaviour. The cuttings taken from lower part of tree crown showed higher percentage of rooting as well as sprouting than those taken from theupper part. Better rooting of cuttings taken from the lower part of the crown of mature trees is found to be related to better nutrients/auxin conditions and more physiological juvenility that is associated with the lower part of the mature trees. Thus,the cuttings from lower position, which rooted better, had higher content of sugar and lower content of starch and nitrogen than the cuttings taken from upper part of crown, which exhibited comparatively poor rooting.