Vol.:(0123456789) In Vitro Cellular & Developmental Biology - Plant https://doi.org/10.1007/s11627-024-10439-8 PLANT TISSUE CULTURE Enhancing Phalaenopsis orchid production: a comparative study of permanent and temporary immersion bioreactors Aylar Mohammadpour Barough 1  · Shirin Dianati Daylami 1  · Ali Fadavi 2  · Kourosh Vahdati 1 Received: 3 December 2023 / Accepted: 12 May 2024 / Editor: Jon Mahoney © The Society for In Vitro Biology 2024 Abstract Plant growth regulators play a crucial role in the proliferation of protocorm-like bodies through somatic embryogenesis in Phalaenopsis orchids. Additionally, media components and cultural systems can impact their proliferation and reduce costs. This research aimed to enhance proliferation rates of orchid protocorm–like bodies and decrease costs of both media providing and culture systems. To achieve this, protocorm explants were cultivated in four different systems: solid, liquid permanent immersion (Erlenmeyer flasks on a shaker), and temporary immersion (RITA ® and FA-Bio bioreactor, a new laboratory mini-bioreactor). The media used included half-strength Murashige and Skoog (1/2 MS), modified FAST medium (MFAST), and low-cost medium (LC). The solid medium contained thidiazuron at concentrations of 0, 1.5, or 3.0 mg L −1 . Solid 1/2 MS without thidiazuron was the control. Protocorm-like bodies in solid LC and MFAST exhibited high chlorophyll and anthocyanin content. Their proliferation rates increased by 32.6% and 29.6%, respectively, while culture costs decreased by 45.2% and 43.1%, respectively, compared to solid 1/2 MS with 3.0 mg L −1 thidiazuron. The production of protocorm- like bodies and their carbohydrate content were significantly higher in MFAST and LC media, compared to 1/2 MS media across all culture systems. The RITA ® bioreactor with liquid LC showed higher proliferation rates than the other treatments. Liquid LC reduced costs by 57.6% compared to solid LC, making it a cost-effective option for mass propagation. The FA-Bio bioreactor reduced costs by 70.5% compared to RITA ® for laboratory research evaluations in liquid culture. MFAST media in FA-Bio bioreactors can be used commercially for cost-effective propagation of Phalaenopsis orchids. Keywords In vitro propagation · Liquid medium · Protocorm-like bodies · Solid medium · Somatic embryogenesis Introduction The Phalaenopsis orchid is the most popular potted and cut flower globally due to its year-round availability, ele- gance, long-lasting nature, and vase life (Li et al. 2022). The cultivation of orchids through in vitro techniques can be initiated using seeds, leaves, or flower spike nodes. Recent reports have introduced the formation of protocorm-like bodies (PLBs) from in vitro cultures of Phalaenopsis as the most effective method for propagation, regeneration, and breeding of these plants, given their ability to proliferate in a wide range of culture media (da Silva 2013a; Li et al. 2022). The production of PLBs was initially reported by Wimber (1963) using the culture of young leaves from the tip of the Cymbidium orchid stalk in Vacin and Went medium (VW) (Da Silva 2013b). Subsequently, the production of proto- corms from young leaves became recognized as an effec- tive method for orchid micro-propagation (Da Silva 2013b). Further research by Begum et al. (1994) demonstrated the production of PLBs and calluses from parenchyma tissues (Da Silva 2013b). Zhou (1995) also obtained protocorms of the Doritaenopsis hybrid orchid and PLBs by adding potato juice to the culture medium (Da Silva 2013b). It has been reported that the addition of plant growth regulators (PGRs) * Ali Fadavi afadavi@ut.ac.ir Aylar Mohammadpour Barough mohammadpor.aylar@ut.ac.ir Shirin Dianati Daylami dianati@ut.ac.ir Kourosh Vahdati kvahdati@ut.ac.ir 1 Department of Horticulture, College of Aburaihan, University of Tehran, Tehran 33916‐53755, Iran 2 Department of Food Science and Technology, College of Aburaihan, University of Tehran, Tehran 33916‐53755, Iran