Direct shoot regeneration from hypocotyls and cotyledon segments of Eucalyptus nitens: Effect of light irradiance during the in vitro germination of donor plants.

LUNA C; GONZALEZ A.M; AYALA, P; SANSBERRO P

La Plata

Congreso; Fourth International Conference of the IUFRO Working Party 2.09.02. Development and application of vegetative propagation technologies in plantation forestry to cope with a changing climate and environment. La Plata (Buenos Aires) Argentina. September 19-; 2016

IUFRO

Eucalyptus nitens Maiden (shining gum) is a frost-tolerant species that can be used as an alternative species of Eucalyptus in some regions where winter temperatures are too low. Unlike most eucalypts, E. nitens is a shy seed bearer. This study was aimed at propagating Eucalyptus nitens using organogenesis. To developed an efficient protocol of shoots bud regeneration, in vitro germination of seeds was achieved on Murashige and Skoog (1962) semisolid medium (agar Sigma-Aldrich ® A-1296, 6.5 g·L -1 ) plus sucrose 30 g·L -1 at 27±1/24±1°C (day/night) temperature and subjected to darkness or indirect white light (58 µmol·m -2 ·s -1 PPFD, 12 h photoperiod) for 6, 10 and 30 days. Subsequently, hypocotyls and cotyledons explants were collected and cultured on a fresh medium of similar composition and supplemented with indoleacetic acid (IBA, 1 µM) and 6-benzyladenine (BA, 2.21 µM). The cultures were incubated under controlled light (118 µmol·m -2 ·s -1 PPFD) and temperature (27±1/24±1°C) conditions. A completely randomized experimental design was used for the experiment, with three repetitions and an experimental unit of ten cultured explants. The results were expressed as a percentage of newly formed vegetative buds per explant. The results were statistically analyzed by analysis of variance (ANOVA) and Tukey test (α=0.05) using statistical software Infostat. After 30 days of incubation, a direct pattern formation of adventitious bud was observed from both tested explants. The best results were obtained using hypocotyls collected from seedlings grown in darkness for 10 days; in which, 40±10% of the explants show multiples shoots without callus proliferation.