Factors influencing the scarification and germination of three montane Sierra Nevada shrubs

Abstract

Following fires in the forested ecosystems of the northern Sierra Nevada, California, early successional communities are often dominated by shrubs that arise from seeds that have remained viable in soil seedbanks for long periods. The germination response of seeds of three seral montane shrub species was investigated following exposure to differing types of heat (wet vs. dry), temperatures, duration of temperature exposure, and differing stratification periods. The highest germination (>60%) of Ceanothus integerrimus was observed for seeds scarified by wet heat at 75-100°C; for 4-8 min. Wet heat was more effective than dry heat in scarifying seeds at all temperatures below 100°C. Dry heat at 120°C killed 68-81% of the seeds. Germination was less than 2% for seeds that were not exposed to any heat (scarification) treatment. Similarly, without stratification following scarification, germination was ≤5%. However, germination was as high as 81.3% for scarification followed by stratification. No significant germination was found for seeds of Arctostaphylos viscida or A. mewukka regardless of treatment. Seeds of these species require another chemical, physical, or environmental factor in order to break embryo dormancy or they may have inherently low germination rates.

Citation

Kaufmann, J.B.; Martin, R.E. 1991. Factors influencing the scarification and germination of three montane Sierra Nevada shrubs. Northwest Science. 65(4): 180-187.