One‐step acclimatization of plantlets using a mist reactor

Abstract

A mist reactor was used to grow and acclimatize carnation plants in vitro without using ex vitro acclimatization techniques. The acclimatization protocol in the reactor consisted of altering the mist-on period during the course of the culture period and a stepwise reduction in the relative humidity surrounding the plants from 98% to 70% relative humidity (RH) during the final week of in vitro growth. After transfer and further growth in a greenhouse for 5 weeks, survival was 91% for plants grown in reactors, 81% from vented boxes, and 50% from unvented boxes. Ex vitro survival directly correlated with increased in vitro rooting and decreased hyperhydration. In vitro rooting also correlated with high-quality plants, but did not significantly correlate with low hyperhydration, as normal plants often lacked roots. After 5 weeks in the greenhouse, the quantity of mid- and high-quality plants obtained from reactors and ventilated boxes was similar. Conditions in the mist reactor can be manipulated to produce plants that are readily acclimatized and are equal or better in quality and yield than plants produced using conventional methods.

Bioreactors, Mist

“…Since the reactors are larger than standard micropropagation boxes and the gas-phase composition and humidity can be controlled, it should be possible to grow plant clones with only one transfer step. Furthermore, by regulating the CO 2 in the gas stream along with the RH, acclimatization of the plantlets can occur in the reactor itself, thus significantly reducing the amount of manual labor (13).…”

Design, Development, And Applications Of Mist Bioreactors For Micropropagation And Hairy Root Culture

“…Plants that are hyperhydrated often do not survive outside of their protected in vitro environment [27]. Using a mist reactor, Correll et al [10] were able to reduce hyperhydration in Dianthus caryophyllus plants by altering the mist feed rate anddutycycle Light intensity, CO 2 , and humidity also affect hyperhydration, and the latter two conditions can be altered using mist reactors [11,12]. CO 2 enrichment has been shown to promote net photosynthesis and prepare plants for ex vitro acclimatization [28] and may significantly reduce the acclimatization period [29,30].…”

“…Buer et al [8] fabricated an acoustically transparent polyurethane window to isolate the medium from the transducer ( Figure 1C) but making the windows was difficult, time consuming, and the starting materials were expensive. Chatterjee et al [9] replaced the custom window with an inexpensive, commercially available polypropylene container ( Figure 2) and this design was successfully used for both hairy root [9] and micropropagation studies [10][11][12]. Similarly, Bais et al [13] used a polycarbonate GA-7 vessel.…”

“…Acclimatization accounts for approximately 30% of the total production cost of micropropagation [14]. Correll and Weathers [11] used a mist reactor to grow and acclimatize carnation plants in vitro without using ex vitro acclimatization techniques, which are expensive, time-consuming, and labour-intensive [14,31]. Ex vitro plant survival rates were higher for plants grown in the mist reactor (91% survival) using the acclimatization protocol described in Correll and Weathers [11] versus a conventional propagation system (GA-7 culture boxes) that only had a 50% survival rate.…”

“…Honda et al [40] described at length an image analysis system for robotics-assisted automated selection of plant tissue in large-scale micropropagation. A mist reactor offers the potential for automating several other stages in micropropagation and combining shoot and root production with acclimatization [11].…”