Conservation seed physiology of the ciénega endemic, (Apiaceae).

Knowledge of seed dormancy and optimal propagation techniques is crucial for successful restoration and reintroduction projects, and determining the seed storage behaviour of a species is critical for the long-term conservation of seeds, further supporting future efforts. (Apiaceae) is a globally critically endangered plant species endemic to ciénega wetlands of southwest North America. To support and conservation efforts of , we asked (i) how does the embryo: seed (E:S) ratio change over time once imbibed, (ii) how does germination respond with varying periods of exposure to cold (5°C) and warm (25°C) stratification, and concentrations of gibberellic acid (GA). By answering these questions, (iii) can dormancy class be inferred, and (iv) what storage behaviour category is exhibited? To answer these questions, we collected seeds in Southern Arizona from one of the few remaining wild populations. We measured embryo growth and tested the effects of cold (0-18 weeks) and warm (0 and 4 weeks) stratification, and 0-1000 ppm gibberellic acid on germination. We also tested the effects of cold (-80°C) dry (~20% equilibrium relative humidity) storage on germination. We found that (i) embryos grow inside seeds prior to germination; (ii) compared to control, cold stratification for at least 6 weeks increased germination and warm stratification had no effect; (iii) 1000-ppm GA had the highest germination success; (iv) therefore this species exhibits morphophysiological dormancy; and (v) seeds are orthodox and can therefore be conserved using conventional storage methods. This information will aid managers in the propagation of that is crucial for reintroduction and restoration projects, and seed banking represents a critical conservation strategy for the preservation of this species.