Seed Germination of Selected Provenances of Atlantic White-Cedar as Influenced by Stratification, Temperature, and Light

Abstract

Seeds of six provenances (Escambia Co., Ala.; Santa Rosa Co., Fla.; Wayne Co., N.C.; Burlington Co., N.J.; New London Co., Conn.; and Barnstable Co., Mass.) of Atlantic white-cedar [Chamaecyparis thyoides (L.) B.S.P.] were stratified (moist-prechilled) for 0, 30, 60, or 90 days at 4 °C. Following stratification, seeds were germinated at 25 °C or an 8/16-hour thermoperiod of 30/20 °C with daily photoperiods at each temperature of 0 (total darkness), 1, or 24 hours. The germination of nonstratified seed did not exceed 18%. Seeds germinated at 25 °C required 60 to 90 days stratification to maximize germination. In contrast, 30 days stratification maximized germination at 30/20 °C. Regardless of stratification duration, germination was generally lower at 25 °C than at 30/20 °C for each provenance. Averaged over all treatments, seeds of the Alabama provenance exhibited the greatest germination (61%), followed by those from Florida (45%), with the remaining provenances ranging from 20% to 38%. However, specific treatments for each provenance induced germination >50%. Germination of seeds not exposed to light was <8%, in contrast with 48% and 55% germination for daily photoperiods of 1 and 24 hours, respectively. Seeds from each of the provenances, except for Alabama, exhibited an obligate light requirement when germinated at 25 °C. At 30/20 °C, the North Carolina, New Jersey, Connecticut, and Massachusetts provenances required light for germination, whereas the Alabama and Florida provenances did not.