Progress and prospects for efficient micropropagation of woody plants

Abstract

Despite the progress made so far, tissue culture studies involving woody plants have always remained quite challenging. Amongst several reasons, lack of a suitable explant source still remains a major bottleneck to limit success. The present review describes the progress in micropropagation of difficult to manipulate woody plant species. It discusses the possibility of forcing epicormic or latent buds in a wide range of adult woody plant species of both temperate as well as tropical origin where procurement of clean, juvenile explant material is extremely scanty. Forcing may be accomplished under different environmental conditions such as fog, mist or lab and media including sand, sawdust, perlite, vermiculite and their combinations. The explants derived from such forced shoots have shown good potential for either rooting directly under greenhouse conditions or further manipulation under in vitro conditions for axillary bud activation, shoot apex proliferation, multiple shoot formation and somatic embryogenesis. This paper intends to review the progress made so far for an efficient micropropagation of several woody species of economic significance making use of the above technology. Several factors limiting the scope of forced epicormic shoots and possible solutions have also been detailed and discussed herein.