Germination of Pulsatilla cernua var. koreana Seeds as Influenced by Harvest Dates and Development of Seeds Analyzed by X-ray Imaging

Abstract

Pulsatilla cernua var. koreana seeds were harvested at six different dates between 16 days after flowering (DAF) (8 Apr.) and 43 DAF (5 May) in 2018 and categorized into six groups based on X-ray images. Germination tests were performed without and with 2 weeks of moist 5 °C treatment [cold stratification (CS)]. Seeds harvested at 38 DAF (30 Apr.) with well-developed vegetative organs (embryo and endosperm) in seeds categorized as A and B (seed A and seed B, respectively) based on the X-ray images were considered fully developed, and 80% of seeds were considered mature. However, the germination rates were less than 26% or 28% when full seeds harvested at 43 DAF received no or 14 days of CS treatment, respectively. Our study suggests that the low germination rate of fully developed seeds as judged by X-ray images showing well-developed embryo and endosperm could result from the presence of dormancy that was not broken effectively by 14 days of CS coupled with the loss of viability caused by 8 months of dry storage at 5 °C.

Seed Longevity and Germinability of Pulsatilla dahurica (Fisch. ex DC.) Spreng after Storage and Accelerated Aging Test

“…Our seeds were not physiologically mature at the time of collection, and it can be assumed that the germination index had been increased after ripening during storage. Yuan et al (2021) also reported that for P. cernua var. koreana seeds collected at different times, the germination rate, germination time, and fidelity were significantly different, and the germination rate increased as the maturity increased.…”

“…However, its seeds are short-lived, and their longevity decreases rapidly over time (Sang et al, 1993). Seed longevity can be highly variable within the same taxon (genus, species) (Priestley et al, 1985;Walters et al, 2005), and may vary depending on maturity, growth environment, and individuals (Kochanek et al, 2009;Yuan et al, 2021).…”