Tissue culture investigations of bamboo—IV. Organogenesis leading to adventitious shoots and plants in excised shoot apices

Abstract

Shoot apices cultured in 2,4-D medium developed a creamy-white callus, subcultures of which do not differentiate shoots in response to variations of auxin/cytokinin levels. In contrast, those cultured in combinations of NAA and BA produced a green, partially organized, granular or nodular callus. Further culture of this callus maintained its partially organized state and resulted in the emergence of adventitious shoots. The new shoots were rooted and readily transplanted in soil. The organogenic callus, developed by intense cell division within axillary buds, resulted in irregular swelling and eventual bursting of buds. New shoot primordia differentiated in superficial cell layers of swollen tissues and specifically in regions with an epidermis. The epidermis formed part of the primordium. Older cultures displayed principally an increase of amorphous callus through swelling occurring in newly formed buds, as well as differentiation of super-numerary buds. The granular or nodular texture was due to aggregates of hard callus interspersed with buds in all stages of development. Although adventitious, the buds were not derived from single cells.