The Development of Isolated Roots of Comptonia peregrina (Myricaceae) in Culture

Abstract

Seedling roots of the sweet fern Comptonia peregrina (L.) Coult. were excised aseptically and cultured in a modified Bonner-Devirian liquid nutrient medium. Root elongation was very slow in the basic medium which contained inorganic salts, B-vitamins, trace elements and 4 % sucrose. The addition of plant hormones including gibberellic acid, indoleacetic acid, and zeatin, alone or in combinations, had little effect on growth. Myoinositol at 10 or 100 ppm doubled the rate of elongation. The effect of this sugar alcohol could not be replaced by scyllitol, D-sorbitol, D-mannitol or by increasing the sucrose concentration. Subcultured root tips showed progressively less elongation in successive transfers. Secondary thickening of the roots, especially in the basal half, occurred in initial passages and in subcultured roots without added hormones. Root buds also occurred spontaneously especially in the basal portions of cultured roots, both in first and in successive passages. An anatomical analysis showed that these buds were endogenous, arising from a secondary cortex of pericyclic origin.