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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Agricultural Genetic Resources Preservation Research » Research » Publications at this Location » Publication #413547
Research Project: Curation and Research to Safeguard and Expand Collections of Plant and Microbial Genetic Resources and Associated Descriptive Information

Location: Agricultural Genetic Resources Preservation Research

Title: Development of a micropropagation protocol for the ex situ conservation of Nuttall’s scrub oak (Quercus dumosa)

Author
item REE, JOSEPH - San Diego Zoo
item POWELL, CHRISTY - San Diego Zoo
item FOLGADO, RAQUEL - Huntington Library, Art Collections, And Botanical Gardens
item PENCE, VALERIE - Cincinnati Zoo & Botanical Garden
item Walters, Christina
item MASCHINSKI, JOYCE - Center For Plant Conservation (CPC)

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2024
Publication Date: 4/20/2024
Citation: Ree, J.F., Powell, C., Folgado, R., Pence, V.C., Walters, C.T., Maschinski, J. 2024. Development of a micropropagation protocol for the ex situ conservation of Nuttall’s scrub oak (Quercus dumosa). Plants. 13(8). Article e1148. https://doi.org/10.3390/plants13081148.
DOI: https://doi.org/10.3390/plants13081148

Interpretive Summary: Establishing tissue cultures from woody explants can prove difficult and often involves extensive experimentation to optimize medium to reduce necrosis and promote proliferative growth. Commercial basal salts are readily available, but there can be substantial adjustments based on the plants' growth requirements. Mineral analysis of field-grown tissues is a way to streamline the optimization process. This approach was used to obtain a microculture medium for buds from the endangered species Quercus dumosa (Nutall's scrub oak). We found substantial improvement of in vitro growth of Q. dumosa compared to commercially available media. This approach will hasten ex conservation efforts of a species that is in rapid decline in situ.

Technical Abstract: Worldwide, oak species are threatened with extinction due to habitat loss, pathogens, and changing fire regimes. Ex situ conservation through tissue culture may protect the remaining genetic diversity of Quercus dumosa, or the coastal sage scrub oak, from further loss. We designed three basal salt formulations based on the mineral composition of shoot tips and first leaves from mature Q. dumosa and explored carbohydrate source, stress-mitigating compounds, and plant growth regulator concentrations to develop a method of cultivating many Q. dumosa culture lines in vitro. All three novel basal salt formulations led to decreased necrosis compared to commercial basal salt formulas WPM, MS, and DKW. Substitution of 30 g L-1 sucrose with glucose and adding 250 mg L-1 ascorbic acid, 20 µM sodium nitroprusside, and 1 mM y-aminobutyric acid improved culture health overall. In an experiment involving 115 culture lines, 0.66 mg L-1 6-benzylaminopurine produced the highest average shoots per explant, but 0.33 mg L-1 produced the greatest proportion of shoots 2 cm or greater. Incubation for 24 hours in 20 mg L-1 indole-3-butyric acid led to the most rooting. These methods show promise for the ex situ conservation of many genotypes of endangered Q. dumosa. Keywords: ex situ conservation; micropropagation; basal salts; antioxidants; in vitro germination