Temperature and photoperiodic control of flower initiation in a New Guinea Impatiens hybrid

1982 ◽  
Vol 60 (4) ◽  
pp. 320-324
Author(s):  
John Simmonds
Keyword(s):  
New Guinea ◽  
Reliable Estimate ◽  
Flower Initiation ◽  
Photoperiodic Control ◽  
Short Day ◽  
New Guinea Impatiens

The effects of photoperiod and temperature on flower initiation and the rate of node production in a New Guinea hybrid Impatiens cv. Starburst were investigated. The node of first flower initiation was not a reliable estimate of the time of flower initiation unless treatment influences on the rate of node production were also considered. Plants maintained at 25 °C responded as quantitative short-day plants; the time of flower initiation was earlier, and the degree of flowering was greater, in 8- and 14-h photoperiods than in 18-h photoperiods. In short (12-h) photoperiods flowering was modulated by temperature. The time of flower initiation was reduced from 27 days at 25 °C to 13 days at 20 °C and to 10 days at 15 °C. Night-break experiments indicated that flowering at 25 °C was subject to photoperiodic control but at 15 °C the plants were "day-neutral."

THE EFFECT OF PHOTOPERIOD ON AXILLARY BRANCH DEVELOPMENT AND FLOWER PRODUCTION OF A NEW GUINEA Impatiens HYBRID

1985 ◽  
Vol 65 (4) ◽  
pp. 995-1000
Author(s):  
JOHN SIMMONDS
Keyword(s):  
New Guinea ◽  
Flower Initiation ◽  
Flower Bud ◽  
Photoperiodic Control ◽  
Flower Production ◽  
Plant Growth Habit ◽  
Branch Development ◽  
Axillary Branch ◽  
Delayed Flowering ◽  
Axillary Branches

The influence of photoperiod and temperature on the production of flowers by a New Guinea hybrid Impatiens, cv. Starburst, was investigated. Delayed flowering below 20 °C was due only to effects on flower bud development. Although flower initiation was day-neutral, the number of flowers produced was significantly influenced by photoperiodic control of axillary branch elongation. In 8-, 14- or 16-h photoperiods axillary branches on the lower nodes remained compact but in a 12-h photoperiod the axillary branches elongated, and flower production on these axillary branches was enhanced. Night-break (NB) treatments indicated that this was a photoperiodic effect. This photoperiodic control of plant growth habit provides a means of regulating the rate of flowering of this cultivar.Key words: Impatiens, photoperiod, flowering, apical dominance

Simulated Water Use and Growth of New Guinea Impatiens (Impatiens X hb.) in Single Pots Using Root Zone Heating

1993 ◽  
Vol 36 (6) ◽  
pp. 1887-1893
Author(s):  
G. E. Meyer ◽  
G. Ridder ◽  
J. B. Fitzgerald ◽  
D. D. Schulte
Keyword(s):  
Water Use ◽  
Root Zone ◽  
New Guinea ◽  
New Guinea Impatiens

scholarly journals Identifying the Optimal Application Rate of Three Fertilizers Used to Grow New Guinea Impatiens

2016 ◽  
Vol 34 (4) ◽  
pp. 118-122
Author(s):  
A.K. Ostrom ◽  
C.C. Pasian
Keyword(s):  
Controlled Release ◽  
Consumer Preferences ◽  
Tap Water ◽  
Consumer Preference ◽  
New Guinea ◽  
Water Soluble ◽  
Plant Weight ◽  
Preference Ratings ◽  
New Guinea Impatiens

This manuscript describes the effect of controlled-release, and water-soluble fertilizers on the growth and quality of New Guinea impatiens (NGI) (Impatiens hawkeri Bull.). Three different fertilizers were applied at three rates each in order to investigate their effect on growth and quality of ‘Paradise New Red.’ NGI. Fertilizer treatments included 1) a 20-4.4-16.6 water-soluble fertilizer (WSF), 2) a 10-1.8-2.5 soybean-based fertilizer (SBF), and 3) a 15-4-10, three-to four-month longevity controlled-release fertilizer (CRF). CRF was applied as a pre-plant at 1×, 0.75×, and 0.5× the label rate. WSF and SBF fertigation rates of 75, 150, and 250 mg·L−1 N (75, 150, and 250 ppm N), respectively, were used based on a common range of fertigation rates in a greenhouse setting from what is considered relatively low, moderate, and high for NGI production. Plants were irrigated or fertigated by hand every 1 to 5 days as needed, based on environmental conditions and plant size, with either approximately 300 mL (10.4 oz) of either tap water or a fertilizer solution. SPAD readings, above ground plant weight, consumer preference ratings, and cumulative flower number were measured and used to calculate a quality index (QI). Optimal fertilizer rates as determined by the QI were found to be 1) CRF at 7.11 kg·m−3 (11.8 lb·yd−3), 2) SBF at 150 mg·L−1 (150 ppm) N, and 3) WSF at 75 mg·L−1 (75 ppm) N. With the application method used in this work, the WSF was more efficient than the SBF because it produced high quality plants with less fertilizer applied. While for the most part overall consumer preference ratings coincided with plant dry weight, there were some exceptions, indicating that consumers can prefer plants that are not necessary the largest as indicated by their dry weights. Consumer preferences may not coincide with typical plant parameters of plant growth all the time. Consumer preferences should be always considered in an industry that sell its products based mainly on their appearance.

scholarly journals Photocontrol of Flowering and Extension Growth in the Long-day Plant Pansy

2003 ◽  
Vol 128 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Flower Development ◽  
Red Light ◽  
Reproductive Development ◽  
Extension Growth ◽  
Separate Experiment ◽  
Flower Initiation ◽  
Minimal Extension ◽  
Short Day ◽  
Long Day ◽  
Light Duration

Plastics that selectively reduce the transmission of far-red light (FR, 700 to 800 nm) reduce extension growth of many floricultural crops. However, FR-deficient (FRd) environments delay flowering in some long-day plants (LDPs), including `Crystal Bowl Yellow' pansy (Viola ×wittrockiana Gams). Our objective was to determine if FR light could be added to an otherwise FRd environment to facilitate flowering with minimal extension growth. In one experiment, plants were grown under a 16-hour FRd photoperiod, and FR-rich light was added during portions of the day or night. For comparison, plants were also grown with a 9-hour photoperiod [short-day (SD) control] or under a neutral (N) filter with a 16-hour photoperiod (long day control). Flowering was promoted most (i.e., percent of plants that flowered increased and time to flower decreased) when FR-rich light was added during the entire 16-hour photoperiod, during the last 4 hours of the photoperiod, or during the first or second 4 hours after the end of the photoperiod. In a separate experiment, pansy was grown under an FRd or N filter with a 9-hour photoperiod plus 0, 0.5, 1, 2, or 4 hours of night interruption (NI) lighting that delivered a red (R, 600 to 700 nm) to FR ratio of 0.56 (low), 1.28 (moderate), or 7.29 (high). Under the N filter, the minimum NI duration that increased percent flowering was 2 hours with a moderate or low R:FR and 4 hours with a high R:FR. Under the FRd filter, 2 or 4 hours of NI lighting with a moderate or low R:FR, respectively, was required to increase percent flowering, but a 4-hour NI with a high R:FR failed to promote flowering. Pansy appears to be day-neutral with respect to flower initiation and a quantitative LDP with respect to flower development. The promotion of reproductive development was related linearly to the promotion of extension growth. Therefore, it appears that in LDPs such as pansy, light duration and quality concomitantly promote extension growth and flowering, and cannot readily be separated with lighting strategies.

scholarly journals Floral Induction in the Short-Day Plant Chrysanthemum Under Blue and Red Extended Long-Days

2021 ◽  
Vol 11 ◽  
Author(s):  
Malleshaiah SharathKumar ◽  
Ep Heuvelink ◽  
Leo F. M. Marcelis ◽  
Wim van Ieperen
Keyword(s):  
Blue Light ◽  
Floral Induction ◽  
Sole Source ◽  
Solar Light ◽  
Growth Chamber ◽  
Flower Initiation ◽  
Dependent Manner ◽  
Led Light ◽  
Short Day ◽  
Short Days

Shorter photoperiod and lower daily light integral (DLI) limit the winter greenhouse production. Extending the photoperiod by supplemental light increases biomass production but inhibits flowering in short-day plants such as Chrysanthemum morifolium. Previously, we reported that flowering in growth-chamber grown chrysanthemum with red (R) and blue (B) LED-light could also be induced in long photoperiods by applying only blue light during the last 4h of 15h long-days. This study investigates the possibility to induce flowering by extending short-days in greenhouses with 4h of blue light. Furthermore, flower induction after 4h of red light extension was tested after short-days RB-LED light in a growth-chamber and after natural solar light in a greenhouse. Plants were grown at 11h of sole source RB light (60:40) in a growth-chamber or solar light in the greenhouse (short-days). Additionally, plants were grown under long-days, which either consisted of short-days as described above extended with 4h of B or R light to long-days or of 15h continuous RB light or natural solar light. Flower initiation and normal capitulum development occurred in the blue-extended long-days in the growth-chamber after 11h of sole source RB, similarly as in short-days. However, when the blue extension was applied after 11h of full-spectrum solar light in a greenhouse, no flower initiation occurred. With red-extended long-days after 11h RB (growth-chamber) flower initiation occurred, but capitulum development was hindered. No flower initiation occurred in red-extended long-days in the greenhouse. These results indicate that multiple components of the daylight spectrum influence different phases in photoperiodic flowering in chrysanthemum in a time-dependent manner. This research shows that smart use of LED-light can open avenues for a more efficient year-round cultivation of chrysanthemum by circumventing the short-day requirement for flowering when applied in emerging vertical farm or plant factories that operate without natural solar light. In current year-round greenhouses’ production, however, extension of the natural solar light during the first 11 h of the photoperiod with either red or blue sole LED light, did inhibit flowering.

Photoperiodic control of development in the pitcher-plant mosquito, Wyeomyia smithii

1972 ◽  
Vol 50 (6) ◽  
pp. 713-719 ◽  
Author(s):  
William E. Bradshaw ◽  
L. Philip Lounibos
Keyword(s):  
Larval Instar ◽  
Pitcher Plant ◽  
Photoperiodic Control ◽  
Wyeomyia Smithii ◽  
Diapause Termination ◽  
Environmental Consequences ◽  
The Third ◽  
Short Day ◽  
Critical Daylength ◽  
Short Days

Wyeomyia smithii diapause in the third larval instar. Long days avert or terminate and short days promote or maintain diapause. Diapause occurs early in the third instar and may be terminated by photoperiodic stimuli without the intervention of chilling or other factors. Fifty percent termination of diapause requires about 3 long days and another [Formula: see text] days are consumed in the third instar for postdiapause development. The critical daylength is identical for both the initiation and termination of diapause, 14.75 h of light per day. But, the photoperiodic clock monitoring diapause decisions is several times as accurate during initiation as in termination, reflecting the more drastic environmental consequences of development misdirection in the fall than in the spring. This accuracy is further enhanced by a prolongation of the second instar under short-day conditions. The doubling in the duration of the second instar exhibits the same critical daylength properties as diapause determination.The third instar is divisible into four distinct developmental periods: prediapause, diapause, termination of diapause, and postdiapause. Methods for quantifying these periods are presented. Similar manipulations could be employed for other diapausing arthropods, regardless of the stage at which dormancy occurs or the cues used in its regulation.

Flowering in Townsville lucerne (Stylosanthes humilis). 1. Studies in controlled environments

1967 ◽  
Vol 7 (29) ◽  
pp. 489 ◽  
Author(s):  
DF Cameron
Keyword(s):  
Light Intensity ◽  
The Other ◽  
Flower Initiation ◽  
Night Temperature ◽  
Short Day ◽  
Critical Daylength ◽  
Stylosanthes Humilis ◽  
Controlled Environments ◽  
Lower Light ◽  
Main Factor

The flowering of seven selections of Townsville lucerne (Stylosanthes humilis HBK) representing a range of maturity types has been studied in the Canberra phytotron. Daylength is the main factor controlling flowering in these selections, all of which showed a strong short day response. At normal temperatures the maximum daylengths at which all plants flowered (the critical daylengths) were 13 hours for the early, 12 hours for the midseason and late-midseason, and 11 1/2 hours for the late selections. However, the midseason selections did flower in a 12 1/2-hour daylength if the light intensity of the supplementary illumination was 20 or 5 ft.c. instead of the normal 50 ft.c. The response of the other selections was not altered at the lower light intensities. Both high night temperature and low day temperature delayed or inhibited flower initiation in the early and midseason selections and these effects were greater at a critical daylength.

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