Ethylene Production and Influence of Silver Thiosulfate on Ethylene Sensitivity of Cut Evergreens
A survey of 16 cut evergreen species found six clustered groupings of species based on ethylene production at 2 and 21C. Ethylene production (in nanoliters per kilogram of fresh weight per hour) at 21C ranged from 26 for Juniperus virginiana to 2800 for Sequoia sempervirens. Exposure to 0.1 or 1.0 ppm ethylene for 72 hours at 2C resulted in minor effects on two species, while significantly delaying senescence of Sequoia sempervirens. Silver thiosulfate (STS) pretreatment decreased or increased longevity of six species, but all effects were minor. Longevity of cut evergreens when held in preservative solution ranged from 14 days for Pinus sylvestris to 56 days for Chamaecyparis lawsoniana. Senescence symptoms observed were needle abscission, desiccation, and/or chlorosis.