Four seedlings derived from 3 cultivars of Coleus Χ hybridus Voss and C. blumei Benth were injured when exposed to 5°C for 24, 32, or 48 hours. An exposure of 32 hours or longer increased the foliar damage of chilled seedlings. In the case of ‘Harlequin’ and ‘Weimar Buckley’ seedlings, chilling injury was apparent during or immediately following the 24, 32, and 48 hours chilling exposure. One selection of ‘Red Rainbow’ displayed no symptoms of chilling injury following the 24-hour treatment, and only minor injury after 32- and 48-hour exposure. The other selection was only slightly more sensitive following these treatments. Seven days after a 48-hour exposure at 5°, 100% of the terminal buds of ‘Red Rainbow’ and ‘Weimar Buckley’ seedlings were dead, but no damage was evident on terminal buds of ‘Harlequin’ seedlings. No apparent injury was observed in any seedlings when exposed to 10° for as long as 48 hours.
An inbred line of geranium seedlings was treated with CEPA and ABA sprays, CCC and CBBP drenches, and combinations of sprays and drenches. CEPA, CCC, and CBBP were physiologically active in altering the growth habits of geranium seedlings. ABA was relatively inactive. The earliest observable responses were dwarfing, stimulation of basal branching, and development of darker green leaves. CEPA alone or in combination with CCC or CBBP stimulated the greatest number of basal branches, but inhibited flower initiation for 70 days. Dwarfing effect was long-lasting in treatments with combinations of CEPA and CCC or CBBP. None of the growth retardant treatments had an effect on fruit development, seed germination, or seedling growth.