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- Author or Editor: Mark P. Kaczperski x
Seedlings of Pelargonium × hortorum `Scarlet Elite' were grown to transplantable size in #406 plug trays. Seedlings were preconditioned for storage by applying 0, 75, 150 or 300 mg l-1 nitrogen using a 15-16-17 fertilizer or growing the seedlings at 10, 15 or 20 C, for 14 days immediately preceding storage. After preconditioning, seedlings were stored in the dark at 5 C for 0, 7, 14 or 21 days, and then transplanted to 10 cm pots and grown to flower under greenhouse conditions. Unstored seedlings flowered fastest when the highest fertility level was maintained during the preconditioning stage. However, fastest flowering of stored seedlings occurred when preconditioned with 150 mg l-1 N. Plants preconditioned at the highest N level had the highest mortality rates during storage. Preconditioning seedlings at 10 or 15 C delayed flowering compared to seedlings grown at 20 C.
Seeds of Pelargonium × hortorum `Scarlet Elite' were germinated in #406 plug trays under fluorescent lights using an irradiance of 100 μmol s-1 m-2 and 18 hr photoperiod and ambient CO2. Upon emergence seedlings were exposed to irradiances of 100, 225 or 350 μmol s-1 m-2 and CO2 levels of 500, 1000, or 1500 μl l-1 for 7 to 35 days after which they were transplanted in 10 cm pots and grown to flower under greenhouse conditions. Seedling height decreased as irradiance increased, and increased as CO2 increased. Seedling quality increased with increasing irradiance and CO2. Elevated CO2 at any irradiance during the seedling stage decreased days to flower during the growing on stage.
Seed of Viola × wittrockiana `Majestic Giant Yellow' were germinated in #406 plug trays at ambient CO2, 25 C and a light intensity of 100 μmol s-1m-2 with an 18 hr photoperiod. At emergence and at successive one week intervals, seedlings were exposed to CO2 levels of 500, 1000 or 1500 μl l-1 and irradiances of 100, 225, 350 μmol s-1m-2 for 7 to 35 days, after which seedlings were transplanted into 10 cm pots and grown to flower in the greenhouse. CO2 at 1000 μl l-1 was as effective as 1500 μl l-1 in accelerating growth in the plug stage. 500 μl l-1 at all irradiances did not accelerate growth significantly. Plants grown at 1000 μl l-1 and 225 μmol s-1m-2 intensity reached the 5 leaf stage up to 14 days earlier than the control, as well as decreasing time to flower during the growing on phase.
Methods of cold storage for rooted cuttings of three cultivars of Pelargonium ×hortorum Bailey were examined. Cuttings were stored from 0 to 10°C for 7 to 56 days. Treatments included packing the cuttings in ice, storing them under irradiance levels of 0 or 50 μmol·m–2·s–1, applying fungicides, varying cutting developmental stages, and varying the day temperatures. Cuttings packed in ice showed signs of chilling injury within 7 days and died. Applications of etridiazole and thiophanate-methyl or metalaxyl and thiophanate-methyl drenches or fosetyl-Al spray did not improve storage performance of the cuttings. Roots of cuttings held 7 additional days in the propagation area before storage grew faster after storage than those of cuttings with less time in the propagation area, but flowering time was not affected. Maintaining night temperatures at 5°C while allowing day temperatures to rise to 10°C delayed flowering by 6 days compared to maintaining a constant 5°C. Rooted cuttings held at 5°C under 50 μmol·m–2·s–1 irradiance for 9 hours each day could be stored up to 56 days with only a 2-day delay in flowering compared to unstored cuttings. Chemicals used were 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole (etridiazole); thiophanate-methyl (dimethyl[1,2-phenylene)bis(iminocarbonothioyl)]bis[carbamate]) (thiophanate-methyl); N-(2,6-dimethylphenyl)-N-methoxyacetyl) alanine methyl ester (metalaxyl); aluminum tris (O-ethyl phosphonate) (fosetyl-Al).
Pelargonium×hortorum L.H. Bailey `Scarlet Elite' seedlings were grown in plugs from seed to transplant size. About 14 days before attaining transplant size, seedlings were exposed to various fertility or temperature regimes (preconditioning treatments), then stored for 1 to 3 weeks at 5C. Seedlings receiving 150 mg N/liter before storage flowered sooner and required less crop time (days to flower – days in storage) than those receiving 0, 75, or 300 mg. Temperature preconditioning at 10 or 15C delayed flowering compared to preconditioning at 20C. Final plant height and dry weight were not adversely affected by varying N levels or temperature during preconditioning. Preconditioning seedlings with 300 mg N/liter resulted in seedling mortality rates up to 16% after 7 days' storage. Low temperature or fertility were not effective preconditioning treatments. Best results were attained by preconditioning seedlings with 150 mg N/liter.
Seed of Petunia × hybrida `Ultra White' were germinated in #406 plug trays at 2.5 C and at a light intensity of 100 μ mol s-1m-2 using a 24 or photoperiod. At germination, seedlings were grown under natural light conditions for 8 hrs (SD) or for 8 hrs with the photoperiod extended to 16 hrs (LD) using incandescent bulbs. At approximately the 6th leaf stage, seedlings were stored at 5 C in the dark or at 12 μ mol s-1m-2 and a 24 hr photoperiod for 0 to 21 days. After storage, plants were potted n 10 cm pots and grown to flowering in a greenhouse. Plants grown under SD to the 6th leaf stage with no cold treatment were shorter. flowered later and had more lateral branching than unstored LD plants. Storage at 5 C decreased time to flower of SD plants and increased branching of LD plants regardless of photoperiod during storage.