Exposure of isolated petals of carnation (Dianthus caryophyllus L.) to ethylene resulted in a rapid loss of fresh weight and “in-rolling,” both of which were prevented by pretreatment of petals with cycloheximide (CHI). Actinomycin D (ActD) had no effect on these responses. Treatment of petals with ethylene also resulted in an increase in O2 uptake, which was also inhibited by pretreatement with CHI. “In-rolling” of petals was prevented only if CHI was applied to petals within 4 hours after beginning the exposure to ethylene, but an 8 hour delay in application of CHI after exposure to ethylene was effective in inhibiting the loss of fresh weight.
‘Nellie White’ Easter lilies were treated with either ancymidol or paclobutrazol as a soil drench (1, 2.5, or 5 mg·pot−1) or as a foliar spray (5 mg·plant−1). Ancymidol significantly retarded plant height at all concentrations and for both methods of application. In addition, ancymidol, at 5 mg·pot−1 soil drench, increased days to anthesis. Paclobutrazol did not retard height in this cultivar; in fact, the 2 lower rates increased height slightly and decreased days to anthesis. Plant height of ‘Ace’ Easter lilies was reduced by paclobutrazol treatments (5,10, or 20 mg·pot−1 soil drench). This cultivar, however, was also more sensitive to ancymidol treatment than ‘Nellie White’. Rates >1 mg ancymidol excessively retarded plant height. Paclobutrazol appears to have limited potential as a growth retardant for Easter lily. Although it must be used in higher amounts than ancymidol to control stem growth, it provides commercially acceptable height retardation over a wider range of treatment rates. Chemical names used: α-cyclopropyl-α-[4-methoxyphenyl]-5-pyrimidinemethanol (ancymidol); and β-[(4-chlorophenyl)methyl]-α-(l,l-dimethylethyl)-lH-l,2,4-triazole-l-ethanol (paclobutrazol).
Freesia (Freesia hybrida Bailey) corms were treated with paclobutrazol or ancymidol as a 5 mg a.i. soil drench, or with paclobutrazol as a 250 ppm preplant corm soak treatment. Both growth retardants significantly reduced plant height and inflorescence length, but had no effect on number of flowering spikes per pot or number of days to flowering. The preplant corm soak treatment was even more effective for height control than the soil drench application. Both compounds can be used to reduce plant height, allowing the adaptation of freesia to pot plant culture. Chemical names used : β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4 triazole-1-ethanol (paclobutrazol) and α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidi nemethanol (ancymidol).
Internode elongation in lily (Lilium longiflorum Thunb.) increased significantly in the uppermost internodes during the development of the flowers. The last 4 internodes contributed as much to plant height as the first 30 internodes. Removal of the flowers reduced internode elongation, and within the range of 1–4 flowers per plant, length of the uppermost internodes was directly related to flower number. Removal of the perianth of the flowers was almost as effective as defloration in reducing internode growth. Application of gibberellic acid to decapitated stems completely replaced the effect of the flowers, whereas indoleacetic acid was only partially effective in restoring internode growth.
Lilies (Lilium longiflorum Thunb.) were treated with ancymidol (A-Rest), propiconazol (Banner), triadimefon (Bayleton), or Mobay RSW0411 as a soil drench or as a preplant bulb soak. At high rates the fungicides triadimefon and propiconazol reduced Easter lily plant height. Neither propoiconazol nor triadimefon were as effective as Mobay RSW0411 or ancymidol in reducing plant height; however, results suggest that chemical treatments for disease and height control may be achieved with the same treatment. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); 1-(2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole (propiconazol); 1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone (triadimefon); β-(cyclohexylmethylene)-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (Mobay RSW0411).