Search Results
Abstract
Lilium longiflorum Thunb. ‘Nellie White’ flower buds developed from visible bud to open flower more rapidly at constant 27°C than at constant 15°. This increased growth rate was most pronounced when buds were less than 6 cm. Once buds were greater than 10 cm, the differences in rate of flower bud growth at 15° compare to 27° was insignificant. Bud development was biphasic, with a relatively slow growth rate up to 6 cm and then an accelerated rate from 6 cm to open flower. The fitted regression line for buds less than 6 cm was: days to flower (DTF) = 37.969 - 8.945 Ln [bud length (L)] — 0.453 [(Temperature (T)]; for buds greater than 6 cm: DTF = 33.258 — 2.039 (L) - 0.736 (T) + 0.044 (L x T). The correlation coefficients for the 2 equations were respectively: r = 0.82 (R 2 = 0.67) and r = 0.93 (R 2 = 0.87).
Abstract
When Alstroemeria ‘Regina’ plants were programmed to flower after 6 or 8 weeks at 5°C treatments, flowering was hastened by forcing plants at 18° vs. 13° greenhouse night air temperature. However, the 18° forcing temperature reduced flower production, flowers per shoot and shoot grade when compared to 13° forcing temperatures. Due to the decrease in flower production observed at 18° forcing temperature, a 13° temperature is recommended. When plants were grown for 16 weeks at 13°, an inductive temperature, or for 16 weeks at 21°, a non-inductive temperature, prior to the 5° inductive treatments, the 13° pretreatment without a 5° treatment was as effective as 8 weeks at 5° following the initial 21° pretreatment when forced at 18°. Thus, the cold requirement can be fulfilled either at 5° for a short period of time (6 to 8 weeks) or at 13° over an extended time span (16 weeks). Total shoot production during the flowering span decreased as the duration of the 5° treatment increased.
Abstract
When Alstroemeria ‘Regina’ shoots were grown in a continuous 13°C air temperature, and the underground structures (rhizomes and roots) were placed in a 5°, 10°, 15°, 20°, or 25° water bath, plants produced 22%, 33%, 13%, 14%, or 5% generative shoots, respectively (Expt. 1). When the underground structures were grown at 13°, there were no differences in percentages of generative shoots, regardless if shoots were in a 13° or 21° air temperature, and regardless if shoots were under short or long photoperiods. When soil temperature was 21° and air temperature was 13°, 12% generative shoots were produced only with a night interruption photoperiod (Expt. 2). Data from these 2 experiments led us to conclude that floral induction was controlled primarily by temperatures to which the underground structures were subjected, regardless of the air temperature or photoperiod. Storage root and rhizome dry weights were promoted by 13° air, 13° soil temperatures and night interruptions with incandescent light. Treatments which had a high percentage of generative shoots also had high root and rhizome dry weights.
Abstract
Night irradiation of stock plants and cuttings during the rooting period with red (R) or incandescent (INC) light resulted in statistical differences in rooting of cuttings of chrysanthemum (Chrysanthemum morifolium Ramat. cvs. Bright Golden Anne and Mrs. Roy) but differences were not large enough to be of commercial concern. Rooting was best when stock plants were irradiated with R light and cuttings were subsquently rooted under INC light and poorest when cuttings from INC irradiated stock plants were rooted under R light.
Abstract
Long photoperiods (either naturally long days or 4-hour night interruptions with low intensity incandescent light) inhibited lateral shoot development and induced early flowering in perpetual flowering carnation (Dianthus caryophyllus). Short photoperiods delayed flowering but enhanced lateral shoot development only when shoots were vegetative. Once a shoot was induced, short photo periods had no influence on time to terminal shoot flower or on subtending vegetative lateral shoot development. Vegetative lateral shoot development was inhibited by night interruption lighting regardless of light source. These data indicate that high flower production in Spring and summer is due to lateral vegetative shoots which begin elongation and growth during the non-flower inductive short days of winter. At higher latitudes low production of flowers may not entirely be due to low photo-synthetic light but to the low number of lateral shoots. This low number of potential flowering shoots is due to highly inductive long days of summer which have caused shoots to flower before subtending lateral shoots can begin growth for future flower production.
Abstract
Alstroemeria L. ‘Regina’ plants grown at 22°C did not flower, regardless of photoperiod treatments. If grown at 13°, plants flowered sooner under long photoperiod treatments than under natural days (ND). Incandescent (Inc) or red light treatments applied as a night interruption (NI) promoted earlier flowering than NI-far-red, ND, or short days (SD). Number of flowering shoots was unaffected by light quality. Plants grown under SD treatments produced the fewest flowering shoots. Flower production was related to early commencement and subsequent duration of the flowering span, as all plants ceased flowering on similar dates. When plants were rotated every 20, 30, or 40 days between SD and NI-Inc light treatments, the days to flower were delayed compared to plants grown continuously (nonrotated) under NI-Inc. Nevertheless, plants which were rotated between the various SD and NI-Inc light treatments flowered sooner than plants under continuous SD. Days to flower were reduced when plants were transferred monthly (December to June) from SD to either ND, 20 hr Inc, or 10 or 20 hr of high-intensity discharge (HID) lights. Flowering was hastened by 20 hr of HID lighting when compared to Inc during the months when the natural photoperiod was less than 12 hr, but had no influence when the 20-HID light treatment commenced after the natural photoperiod was greater than 12 hr. Maintaining plants under SD past January delayed the start of flowering, regardless of subsequent light treatments.
For chrysanthemum [Dendranthema × grandiflorum (Ramat.) Kitamura], the hypothesis that a 12-hr 5C or 13C dark treatment could be used in conjunction with a 12-hr 27, 21, 17, or 13C light treatment for rapid flowering when applied during certain developmental stages was valid. Flowering of `Bright Golden Anne', planted on 23 Sept., was not delayed by 12-hr light/12-hr dark growth chamber treatments of 21/5C or 27/13C (day/night) if treated from planting (P) of the rooted cutting to the start of short days (SD), 3 weeks after start of SD to visible bud (VB) (SD + 3 to VB), or from VB to flower (F) when compared to the glasshouse control plants grown at 21/18C. Plants responded similarly if grown at 13/13C or 21/21C, but flowering was delayed compared to the 17/17C glass house control. Delays were absent, however, when 13/13C was used from P to SD, SD + 3 to VB, or when 17/13 or 21/13C was used from VB to F.
Abstract
Alternanthra amoena Voss, Coleus × hybridus Voss., Hedra helix L., Pelargonium × hortorum Bailey, Peperomia obtusifolia L.,Pilea cadierei Gagnep. & Guillaum, Pilea ‘Moon Valley’ and Pilea involucrata ‘Panamegia’ Sims were grown under normal photoperiods (ND), short photoperiods (SD) and several night lighting regimes using red, incandescent, or far red light. Lateral branching and cutting production was promoted on P. ‘Moon Valley’ under SD while flowering was inhibited. P. ‘Moon Valley’ and P. involucrata flowered under long days. The remaining plant species produced more cuttings under ND or the night lighting treatments when compared to SD. Cycling P. ‘Moon Valley’ and P. involucrata between SD and day continuation red lighting treatments every 20 days significantly increased cutting production on plants compared to plants grown continuously under SD or ND.
Abstract
Placing lily plants in complete darkness, with or without 12 hr per day of low intensity incandescent (Inc) lighting for 5 days at 5 day intervals during the first 40 days of growth after emergence (E) had no influence on final flower bud number. Low intensity Inc lighting given as a 4 hr night interruption under natural daylight (ND) conditions for 10 days at various intervals during the first 40 days after E had no horticulturally significant influence on flower bud number. Final lily plant heights were controlled by photoperiod. Heights were reduced when plants were forced under 8 hr photoperiods (SD) when compared to ND forced plants. Heights of ‘Ace’ and ‘Nellie White’ plants were reduced by 29% and 45% when forced under SD from E to flower (F), by 19% and 42% when forced from 30 days after E to F, and by 20% and 20% when forced from visible bud to F. Repetitive light/dark cycles of 4, 6 or 12 hr had no effect on lily flower bud development rate from the time buds were 6–12 cm in length to anthesis.