Abstract

In this study, we reported the establishment of a simple protocol for the micropropagation and acclimatization of Lonicera japonica Thunb. Branches with dormant buds were collected from mature L. japonica and sprouted in a greenhouse. Tip and node segments were used as starting material for in vitro proliferation in woody plant medium (WPM). In the first assay in which explants from five different species of Lonicera were used, 95.0% of the tip segments produced new axillary shoots, thus proving to be the best explant type. Afterwards, material from L. japonica Thunb. was used to test for plant growth regulator (PGR) combination. Shoots from L. japonica were used to assay in vitro rooting using six different WPM media. Rooting percentages were high for all media and varied between 83 and 95%. For acclimatization, two approaches were assayed: the use of previously rootedin vitro plants and the direct acclimatization of shoots. After five weeks, 95.0% of the in vitrorooted plants were successfully acclimatized and 88.7%, was attained by direct acclimatization of shoots with two years shoot immersed in GA₃ solution. These results proved that there is no need for a previous in vitro rooting step and that direct acclimatization can effectively reduce time and costs. Thus, the micropropagation and acclimatization of L. japonica can be divided into only two steps: proliferation of shoots in WPM and direct acclimatization of these shoots in a sterile soil mixture, or direct acclimatization of two years shoot immersed in GA₃ solution for 8 h.

Key words: Lonicera japonica Thunb., node segment culture, micropropagation, direct acclimatization.

Abbreviation

ANOVA, Analysis of variance; BA, N₆-benzylaminopurine; IAA, indole-3-acetic acid; IBA, butyric acid; NAA, α-naphthaleneacetic acid; WPM, woody plant medium;PGR, plant growth regulator.