Micropropagation of Brassavola nodosa (L.) Lindl. using SETIS™ bioreactor

Brassavola nodosa (L.) Lindl. is a tropical epiphytic orchid showing characteristics of interest for the ornamental nursery industry, as well as considered as an endangered species. Problems with traditional propagation methods limit the development of a large-scale commercial production system. The use of micropropagation has been investigated for this species, and the use of liquid in vitro systems showed potential for use of temporary immersion systems, also called temporary immersion bioreactors (TIB) for micropropagation of B. nodosa . This study evaluated the efficiency of the SETIS™ TIBs for the micropropagation of B. nodosa . Explants consisting of young shoots tips measuring between 0.3 and 0.5 cm were collected from 1-yr-old in vitro seedlings of B. nodosa and used for shoot multiplication. Four culture systems were evaluated: a semi-solid in vitro system consisting of 160 mm × 100 mm TP1600 Microbox containing 500 ml semi-solid medium as a control, and a liquid in vitro system consisting of 4 L temporary immersion bioreactor (SETIS™, VERVIT, Belgium) containing 500 ml liquid medium with immersion and aeration frequencies of 2 h, 4 h, and 8 h. For all bioreactor treatments, duration of immersion and aeration was 2 min. Results showed that temporary immersion of B. nodosa explants with a frequency of 2 h and duration of 2 min returned the highest multiplication rates, with 4.6 shoots produced per explant compared with 2.8 shoots per explant in semi-solid agar-based systems. The use of bioreactors also promoted increased growth and development and in vitro rooting, therefore improving survival, and facilitating acclimatization of in vitro-derived plantlets. This is the first study demonstrating a successful protocol for micropropagation of B. nodosa using SETIS™ bioreactors, which could have significant value and impact for the commercial production of this species as well as for conservation purposes. Key message Micropropagation of Brassavola nodosa was achieved using SETIS temporary immersion bioreactors, showing good multiplication rates, increased growth and development and in vitro rooting, thus improving survival and acclimatization ex vitro.