Improving Shoot Survival In Vitro Through Ethylene Inhibition

Max Winkeljohn

Published May 2023 in International Oaks No. 34: 159–164

Abstract

To adequately meet the challenges of conserving threatened oak species, a wide array of strategies and techniques are necessary, including ex-situ methods such as in-vitro tissue culture. The ability to initiate and maintain an in-vitro culture line is key both to preserving genotypes through cryopreservation and to growing plants to be used for reintroductions. However, initiating a culture line is not always successful; oaks in particular are prone to stress responses such as browning and thus can be difficult to initiate into culture. This is especially problematic when working with very rare species. Therefore, it is imperative that shoot survival in culture is maximized in order to ensure that these ex-situ conservation strategies have the highest chance of success. To address this issue, we investigated whether the inclusion of silver thiosulfate (STS), a known inhibitor of the plant stress hormone ethylene, would improve the survival of freshly cultured shoots. Over the course of three years, fresh shoots were collected in the spring from five different oak species and cultured onto a standard growing medium with and without STS. Shoots were then grown at a constant 26 °C for one month, at which point they were assessed for survival. Overall, we found a modest, but significant, increase in survival when shoots were cultured onto medium containing STS. This research addresses one of the main challenges to ex-situ conservation and provides a potential solution that could increase our capacity to preserve threatened oak species.

Keywords

ex-situ conservation, in-vitro culture, Quercus, silver thiosulfate

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