Abstract Detail

Conservation Biology

Wolkis, Dustin [1], Walsh, Seana [2].

Seed conservation physiology of four Hawaiian endemic taxa .

Seed banking is the most efficient method to conserve plant species ex situ. However, not all species’ seeds can be stored under the same conditions or indefinitely. Although cryogenically stored seeds may result in a 20,000-fold increase in longevity, no conditions render seeds immortal. In addition, seeds of some species are dormant at seed maturity, and may require a dormancy breaking treatment for use in restoration and conservation projects. Thus, predicting longevity and determining regeneration intervals of stored seeds, and knowing the class of seed dormancy a species exhibits, is of direct relevance for conservation managers. Different aspects of seed conservation physiology were investigated among four Hawaiian endemic taxa in order to optimize storage conditions and attain highest germination success for seeds of those taxa. Brighamia insignis and B. rockii are Critically Endangered with possibly one and less than 50 individuals remaining in the wild, respectively. Although seeds are desiccation tolerant, viability declines more rapidly in subfreezing compared to cool temperatures (intermediate – freeze sensitive). Using the Ellis and Roberts improved equations for the prediction of seed longevity, regeneration intervals at a 50% decline from maximum germination (usually initial viability; P₅₀) were identified for seeds stored under constant conditions for over two decades. P₅₀ for B. insignis and B. rockii was 8 and 11 years, respectively. Seeds of Malvaceae species have been reported to exhibit physical dormancy (PY). Hibiscus waimeae subsp. hannerae and H. waimeae subsp. waimeae are two Kaua?i single-island endemic taxa of conservation importance. With respect to these two taxa we asked; 1) are seed coats water-impermeable, 2) do these taxa exhibit the syndrome of germination requirements typical of those with PY, and if so, 3) how can PY be alleviated with highest germination success? Seed coats were water-permeable and imbibition was fastest in seeds that had been mechanically scarified. Percent germination was highest in the control and soak treatment. A seed dormancy breaking pre-treatment is not necessary for uniform and successful germination for these taxa. Our results have direct relevance for managers working to conserve and propagate these taxa of conservation importance.

1 - National Tropical Botanical Garden, Science & Conservation, 3530 Papalina Rd, Kalaheo, HI, 96741, United States
2 - National Tropical Botanical Garden, Science And Conservation, 3530 Papalina Road, Kalaheo, HI, 96741, United States

Keywords:
Brighamia
Hibiscus
seed physiology
seed dormancy
Seed Longevity
germination ecology
endangered
endemic
Kauaʻi
Hawaiʻi
Conservation.

Presentation Type: Oral Paper
Session: 43, Conservation Biology II
Location: 106/Mayo Civic Center
Date: Wednesday, July 25th, 2018
Time: 1:45 PM
Number: 43002
Abstract ID:892
Candidate for Awards:None