METABOLIC CHANGES DURING ROOTING IN STEM CUTTINGS OF 5 MANGROVE SPECIES

Vegetative propagation through rooting in stem cuttings in five tree m angroves namely Bruguiera parviflora, Cynometra iripa, Excoecaria agal locha, Heritiera fomes, and Thespesia populnea using IAA, IBA and NAA was reported. Spectacular increase in the root number was noted in the cuttings of H. fomes and C. iripa treated together with IBA (5000 ppm ) and NAA (2500 ppm). The highest number of roots was obtained with IB A (2500 ppm) and NAA (500 ppm) in E. agallocha. B. parviflora and T. p opulnea responded better to IAA and IBA treatment. The species specifi c variation in the rooting response to exogenous application of auxins was reflected in the metabolic changes during initiation and developm ent of roots in cuttings. Biochemical analysis showed increase of redu cing sugar in the above-girdled tissues at initiation as well as subse quent development of roots which was further enhanced by the use of au xins. Decreases in the total sugar, total carbohydrate and polyphenols and increase in total nitrogen were recorded in the girdled tissues a nd the high CIN ratio at the initial stage helped in initiation of roo ts in all the species. Interaction of IBA and NAA promoted starch hydr olysis better than IAA and IBA during root development and subsequentl y reduced the CIN ratio and increased the protein-nitrogen activity du ring root development which suggest the auxin influenced mobilization of nitrogen to the rooting zone.