Effect of BAP and ZEA Growing Period on Multiplication of Eucalyptus sp. in RITA® Bioreactor

Abstract

The objective of this study was to evaluate the effect of different cultivation periods with 6‐benzylaminopurine (BAP) and zeatin (ZEA) in bioreactor RITA® on multiplication rate, shoots physiological vigor and hyperhydricity rate. The explants used were apical buds of a Eucalyptus grandis × E. urophylla clone established in vitro and cultured in bioreactors RITA® in four different exposure periods (0 to 10, 10 to 20, 20 to 30 and 0 to 30 days) to the growth regulators BAP and ZEA at 0.5 μM in MS culture medium. Explants cultured in BAP presence showed a higher multiplication rate of new shoots compared to cultured with ZEA. The 0 to 30 days cultivation period in the presence of BAP promoted greater hyperhydricity, shoot number and percentage of elongated shoots. Explants cultured on ZEA presence in the same cultivation period were more healthy and vigorous due to the lower hyperhydricity rate. These results demonstrate the difference in growth and quality of the crop due to the type of cytokinin used in vitro culture.