ABSTRACT

Forest trees were among the first plants cultured in vitro. Gautheret (1940) reported formation of adventitious buds in cultured cambial explants of Ulmus campestris, and Jacquiot (1949) extended the research with this species, using cambium from trees up to 180 years old. Mathes (1964) reported in vitro production of both roots and shoots in callus cultures of Populus tremuloides, but it was not until 1968 that Wolter (1968) produced entire plantlets of this species by inducing shoot formation and subsequent rooting of the shoots in vitro. In the same year,

Winton (1968) obtained complete plantlets from triploid P. tremuloides callus, demonstrating that selected genotypes could be propagated in vitro. Among conifers, the first in vitro regeneration was accomplished by Sommer et al. (1975), who induced adventitious bud production on seedling cotyledons of Pinus palustris.