Effect of storage time,site and floral morph on seed germination of the threatened distylous primrose Primula cusickiana var. maguirei

Ex situ conservation of rare plant species requires an understanding of germination requirements. We report the first successful germination trials for Maguire primrose (Primula cusickiana var. maguirei[L.O. Williams] N.H. Holmgren & S. Kelso), a threatened perennial herb narrowly restricted to a 20‐km canyon in northern Utah, USA. Seeds collected from different sites (upper or lower canyon populations) and flower morphs (pin or thrum) that had been stored for either 1 or 2 years were cold, moist stratified in darkness at 1–2°C for 270 days. Independent of treatment, time to first germination was approximately 75 days, time to 50% germination (T₅₀) was approximately 165 days, and total germination was 55.8%. Higher mean germination was observed in seeds stored for 2 years compared with seeds stored for 1 year, as well as in seeds from pin flowers compared with thrum flowers. There was not a significant effect of site on mean germination, but there was a significant storage time × site interaction. Seeds stored for 2 years also had a lower mean T₅₀ versus seeds stored for 1 year. In addition, seeds from upper canyon populations had a higher mean T₅₀ than those from lower canyon populations. Our results suggest that short‐term storage should not significantly decrease seed viability, and that both flower morph and canyon location may influence germination. Evidence suggests that germination patterns are adaptive. Our results contribute to our understanding of the germination biology of P. cusickiana var. maguirei and inform future conservation efforts for this threatened species.     

Long-distance Transport of Reduced Sulphur in Spruce (Picea abies L.)

Individual needles of 4-year-old spruce trees (Picea abies L.)were exposed to ³⁵S-GSH via the cut surface of the needle tipfor 2–3 h at different times during the growing season.From the previous year's source needle, ³⁵S-GSH was exportedinto the twig and translocated predominantly towards the twigapex. Independent from the growing season, transport towardsthe stem did not exceed 20% of the radioactivity recovered fromthe tissue samples. In July, the new needles appeared to bemetabolic sinks for reduced sulphur as indicated by the higherpercentages of both soluble and insoluble ³⁵S in this twig section,as compared to the previous years' needles. In October, thenew needles were no longer found to be a preferential sink forreduced sulphur. Estimates of the rate of GSH export from thesource needle in the light (2.5–11.3 nmol GSH g