REGENERATION OF PLANTS FROM LONG-TERM ROOT CULTURE OF LIME, CITRUS-AURANTIFOLIA (CHRISTM) SWING

Excised root culture of lime, C. aurantifolia, was established in Murashige & Skoog medium containing 3% sucrose. De novo shoot bud initiation was recorded in basal medium at a low frequency during three years of continuous culture. The effect of indole-3-acetic acid and benzyladenine (BA) were investigated on root growth and shoot morphogenesis. Inclusion of BA in the culture medium had an important effect on root growth and shoot elongation: the frequency of shoot regeneration was only slightly improved by the growth regulator treatment. Shoot bud differentiation occurred at the proximal region of the root at or just distal to the cut end. Histology of shoot regeneration revealed the endogenous origin of the shoot buds from the pericycle tissue of the root. The regenerated plants contained normal diploid chromosome number (2n = 18) and have been established in soil.