No abstract

Sourwood seed held at a constant temperature of 25°C (77°F) exhibited the highest germination percentage when exposed to 4 or more hours of light daily. There were no significant differences in germination percentages among seeds exposed to 4, 8 or continuous light during each 24 hour cycle. Seeds exposed to 1 hour of light daily and subjected to 20°C (68°F), 22.5°C (72.5°F), 25°C (77°F), 28°C (82.4°F), 25/15°C (77/59°F) or 30/20°C (86/68°F) exhibited the highest germination percentages at the alternating temperatures. Further, germination interval was shorter when seed were exposed to 30/20°C (86/68°F) than 25/15°C (77/59°P).

Comparison of stratified and nonstratified seed demonstrated that at 25° C (77° F), as duration of stratification increased from 0 to 60 days, germination percentage also increased. However, an opposite effect occurred for seed exposed to alternating temperatures of 30/20° C or 25/15° C (86/68° For 77/59° F). There were no significant differences observed in the final germination percentage between seed stratified for 30 days and nonstratified seed. Stratification hastened germination and decreased the light required for germination.