Notes: Stratification of Seeds of Western and Utah Juniper

Author： Young James A. Evans Raymond A. Budy Jerry D. Palmquist Debra E.

Publisher： Society of American Foresters

ISSN： 0015-749X

Source： Forest Science, Vol.34, Iss.4, 1988-12, pp. : 1059-1066

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Abstract

Seeds of western juniper (Juniperus occidentalis subsp. occidentalis Hook.) and Utah juniper [J. osteosperma (Tort.) Little] are highly dormant when freshly harvested. Cool-moist stratification at 5°C for 14 weeks in vermiculite enhanced subsequent emergence of seedlings of both species, but total emergence was still low. The year of seed production greatly influences the viability of seedlots. Dry storage for 1 to 4 years at room temperatures did not enhance germination. Outdoor stratification, over winter, in sand, enhances subsequent emergence depending on the environment of the stratification site. The year of seed production also interacts with outdoor situations. Repeat stratification treatments, interrupted by 8-week continuously wet-emergence-assay periods in the greenhouse and dry storage during the summer were cumulative for increased seed germination of both species. Interrupted treatments were more effective than continuous stratification in excess of the optimum duration to enhance germination. Stratification in aqueous solutions with near saturation of the solution with oxygen increased subsequent emergence of seedlings of western and Utah juniper to about 50%. Similar treatments using aqueous solutions of 0.289 m mol L^-1 gibberelin (GA₃) enhanced subsequent emergence of seedlings of western juniper to better than 80%. For. Sci. 34(4):1059-1066.