Orchid Micropropagation Using Conventional Semi-Solid and Temporary Immersion Systems: A Review

Abstract

Orchids, with their astonishingly stunning flowers, dominate the international floricultural market. They are considered prized assets for commercial applications in pharmaceutical and floricultural industries as they possess high therapeutic properties and superior ornamental values. The alarming depletion of orchid resources due to excessive unregulated commercial collection and mass habitat destruction makes orchid conservation measures an extreme priority. Conventional propagation methods cannot produce adequate number of orchids, which would meet the requirement of these ornamental plants for commercial and conservational purposes. In vitro orchid propagation using semi-solid media offers an outstanding prospect of rapidly producing quality plants on a large scale. However, the semi-solid (SS) system has shortcomings with low multiplication rates and high production costs. Orchid micropropagation using a temporary immersion system (TIS) overcomes the limitations of the SS system by reducing production costs and making scaleup and full automation possible for mass plant production. The current review highlights different aspects of in vitro orchid propagation using SS and TIS and their benefits and drawbacks on rapid plant generation.

Bioactive compounds in Laelia speciosa (Orchidaceae) seedlings grown in temporary immersion bioreactor

“…This is the first work where the cultivation of L. speciosa in a TIB has been documented. Until now, temporary immersion systems have been used for the cultivation of other orchids, such as Phalaenopsis sp., Vanilla planifolia, Cattleya walkeriana, Dendrobium candidum and Epidendrum fulgens (Nongdam et al, 2023), but not for L. speciosa. Among the advantages of using the TIB are cost reduction and greater simplicity when scaling the process.…”

“…The liquid medium employed in this study supported culture for 8 weeks. The successful cultivation of L. speciosa biomass in the TIB can likely be attributed to favorable operating parameters, as factors such as immersion time, medium volume, and photoperiod are known to influence tissue growth in temporary immersion systems (Nongdam et al, 2023).…”

Improving micropropagation of Moringa oleifera: The use of semi-solid medium for rooting and sucrose-free liquid medium combined with temporary ventilation for hardening

“…This causes root injury, leading to poor water and nutrient absorption, and the injuries created are very susceptible to infection by soil pathogens, contributing to the high percentage of mortality after soil transfer. One strategy to minimize root injury is to use a softer medium for rooting the plantlet, as has been done in the micropropagation of Centella asiatica [22], Corema album [23], Capparis spinosa [24], and various orchid species [25]. Results of the rooting experiment showed that the root injury observed in plantlets grown on the semi-solid medium solidified with 4 g/L agar was lower than that observed in plantlets grown on the harder solid medium solidified with 6 and 8 g/L agar.…”

Ecosystem services provided by orchids: a global analysis

“…In order to minimize excessive orchid extraction, artificial propagation techniques of orchid seeds have improved, helping to reduce the demand for wild plants (Nongdam et al 2023). However, drawbacks have been found in the use of artificially grown medicinal orchids, mainly in Asia, where they are considered inferior in quality to ornamental orchids and have a much lower market price than their wild counterparts (Liu et al 2014).…”