Ageratum, begonia, marigold, and salvia seedlings in plug cells were stored in coolers to determine the effects of temperature, light, and storage time on growth and forcing time of seedlings after transplanting, and to determine the optimum storage temperatures for each crop. Photosynthetic photon flux densities of 0, 1, and 5 μmol·m-2.s-1 were combined with temperatures of 0.0, 2.5, 5.0, 7.5, 10.0, and 12.5C to create 18 storage environments. Sample plants were removed from each treatment at 1-week intervals for 6 weeks, and were forced into flower. In all four species, temperatures of 0.0 and 2.5C caused chilling injury and then death as plants were stored for progressively longer periods. Storage at 0.0 and 2.5C also delayed flowering when chilling injury was not severe enough to cause death. In general, plants stored better in the light than in darkness. Darkness tended to limit the time seedlings could be stored, but for each crop, the addition of just 1 μmol·m-2.s-1 extended the storage durations to 6 weeks at one or more temperatures. Storage of all four species was possible for 6 weeks, but there were significant variations between the temperatures and storage durations each species could tolerate. Optimal temperatures were 5-7.5C for begonia, 5C for marigold, and 7.5C for salvia and ageratum.
Royal D. Heins, Nathan Lange, and Thomas F. Wallace Jr.
Royal D. Heins, Thomas F. Wallace Jr., and Susan S. Han
Chlorosis of Easter lily (Lilium longiflorum) lower leaves causes significant economic loss. Lily plants growing in 15-cm pots were sprayed 30, 60, or 90 days after emergence or at 60 and 90 days after emergence with 25 to 100 ppm each of benzyladenine and GA4+7 from Promalin (Abbott Chemical Co.) and were grown pot-to-pot until flower. Chlorotic leaf count at flower decreased as Promalin concentration increased; plants sprayed at 60 days had the smallest chlorotic leaf count. Chlorotic leaves at flower varied from 28% for control plants to 10% for plants sprayed with 100 ppm at 60 days and from 36% to 17% 3 weeks later, respectively. The Promalin sprays promoted significant stem elongation, but differences in height at flower were only 2 cm. Plants sprayed with 100 ppm at 30 days averaged one deformed flower per plant; plants sprayed at 60 days and 60 and 90 days averaged 0.0 and 0.1 deformed flower per plant, respectively. Additional trials in which only the lower part of the plant was sprayed prevented any chlorotic leaves without any significant effect on final height or flower bud quality.