High-frequency protocorm-like bodies and shoot regeneration through a combination of thin cell layer and RITA((R)) temporary immersion bioreactor in Cattleya forbesii Lindl.

An efficient in vitro mass propagation through protocorm-like bodies (PLBs) was established in Cattleya forbesii Lindl., a commercially important orchid. Whole PLBs (W-PLB) and transverse thin cell layers of PLB (tTCL-PLB) explants were cultured in RITA((R)) bioreactors based on temporary immersion system. Explants were transferred in semi-solid or RITA((R)) bioreactor for protocorm production or shoot regeneration. The effect of different immersion frequencies, medium volumes and inoculum densities were studied and optimized. RITA((R)) bioreactor cultures were found to be superior compared with semi-solid cultures regarding PLB production and shoot regeneration. tTCL-PLB explant types cultured in the RITA((R)) bioreactor with immersion for 1min/4h, 250mL of medium and 20 explants showed the highest number of PLBs per RITA((R)) (2237 PLBs) and per explant (111.9 PLBs). The highest number of PLBs per explant was 21 times higher than those from semi-solid culture. The highest number of shoots per RITA((R)) (3998 shoots) and per explant (199.9 shoots) were observed on tTCL-PLB cultured in RITA((R)) bioreactor (1min/4h; 150mL of medium and 20 explants). The highest number of shoots per explant was 95 times higher than those grown on semi-solid culture. Mass propagation of PLBs and shoots of C. forbesii Lindl. using combined thin cell layer and RITA((R)) temporary immersion has been adapted in commercial practice.