scholarly journals The Effects of End-of-the-day Red and Far-red Light on Growth and Flowering of Petunia ×hybrida `Countdown Burgundy' Grown under Photoselective Films

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 131-133 ◽  
Author(s):  
Ilias F. Ilias ◽  
Nihal Rajapakse
Keyword(s):  
Adverse Effects ◽  
Petunia Hybrida ◽  
Stem Elongation ◽  
Red Light ◽  
Main Stem ◽  
Percentage Increase ◽  
Minute Exposure ◽  
Long Day ◽  
Long Day Plants ◽  
Delayed Flowering

The objective of this research was to investigate if brief exposure to end-of-the-day (EOD) red (R) or far red (FR) light can overcome the flowering delay of petunia (Petunia ×hybrida Vilm.-Andr. `Countdown Burgundy') grown under FR deficient greenhouse environments with no adverse effects on stem elongation. Plants were grown under clear, FR, and R light absorbing greenhouse films (control, AFR, and AR films, respectively) and exposed to R or FR light at the end of the photoperiod for 15 minutes. At flowering, main stem of plants grown under the AR film was about 17% longer and that of AFR film grown plants (without EOD treatment) was about 50% shorter than control plants. EOD-R light reduced stem elongation of control plants but had no effect on AFR or AR film-grown plants. EOD-FR light increased stem elongation in plants grown under AR and AFR films but the percentage increase was greater under AFR film (7%, 19%, and 64% increase in control, AR, and AFR films, respectively). However, plants that received EOD-FR light under AFR film were 25% shorter than control plants that received no EOD light. AFR film delayed flowering by 11 days but AR film had no effect. Fifteen-minute exposure to EOD-R or -FR light had no effect on flowering under control and AFR film. Although the exposure to brief EOD-FR partially increased stem elongation, it was not sufficient to accelerate flowering. Treatments to enhance flowering can cause stem elongation. Therefore, care should be taken to avoid improper crop timing, especially with long-day plants.

scholarly journals Specific Functions of Red, Far Red, and Blue Light in Flowering and Stem Extension of Long-day Plants

2001 ◽  
Vol 126 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Blue Light ◽  
Flower Development ◽  
Red Light ◽  
Wide Band ◽  
Extension Growth ◽  
Photon Flux ◽  
Flower Initiation ◽  
Stem Extension ◽  
Long Day ◽  
Long Day Plants

For many long-day plants (LDP), adding far red light (FR, 700 to 800 nm) to red light (R, 600 to 700 nm) to extend the day or interrupt the night promotes extension growth and flowering. Blue light (B, 400 to 500 nm) independently inhibits extension growth, but its effect on flowering is not well described. Here, we determined how R-, FR-, or B-deficient (Rd, FRd, or Bd, respectively) photoperiods influenced stem extension and flowering in five LDP species: Campanula carpatica Jacq., Coreopsi ×grandiflora Hogg ex Sweet, Lobelia ×speciosa Sweet, Pisum sativum L., and Viola ×wittrockiana Gams. Plants were exposed to Rd, FRd, Bd, or normal (control) 16-hour photoperiods, each of which had a similar photosynthetic (400 to 700 nm) photon flux. Compared with that of the control, the Rd environment promoted extension growth in C. carpatica (by 65%), C. ×grandiflora (by 26%), P. sativum (by 23%), and V. ×wittrockiana (by 31%). The FRd environment suppressed extension growth in C. ×grandiflora (by 21%), P. sativum (by 17%), and V. ×wittrockiana (by 14%). Independent of the R: FR ratio, the Bd environment promoted stem extension (by 10% to 100%) in all species, but there was little or no effect on flowering percentage and time to flower. Extension growth was generally linearly related to the incident wide band (100 nm) R: FR ratio or estimated phytochrome photoequilibrium except when B light was specifically reduced. A high R: FR ratio (i.e., under the FRd filter) delayed flower initiation (but not development) in C. carpatica and C.×grandiflora and inhibited flower development (but not initiation) in V.×wittrockiana. Therefore, B light and the R: FR ratio independently regulate extension growth by varying magnitudes in LDP, and in some species, an FRd environment can suppress flower initiation or development.

scholarly journals 569 Photoselective Filters Affect Flowering and Stem Extension In Viola ×wittrockiana and Pisum sativum

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 544D-544 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Pisum Sativum ◽  
Light Quality ◽  
Stem Elongation ◽  
Plant Morphology ◽  
Photon Flux ◽  
Spectral Filters ◽  
Density Control ◽  
Long Day ◽  
Long Day Plants ◽  
Peduncle Length

For many plants, light quality has a pronounced effect on plant morphology; light with a low red (R, 600 to 700 nm) to far-red (FR, 700 to 800 nm) ratio promotes stem elongation and a high R: FR, or blue light (B, 400 to 500 nm), suppresses it. In addition, FR light is required for rapid flowering in some species, particularly for long-day plants. Our objective was to quantify how flexible spectral filters, which selectively reduce FR, B, or R, influence plant height and flowering of the quantitative long-day plants Pisum sativum L. `Utrillo' and Viola ×wittrockiana Gams. `Crystal Bowl Yellow'. Plants were grown at 20 °C with reduced FR, B, or R environments or with a neutral density control (C) filter. Calculated phytochrome photoequilebria were 0.78, 0.73, 0.71, or 0.46 for the altered FR, B, C, or R environments, respectively. All filter treatments transmitted a similar photosynthetic photon flux. Sixteen-hour photoperiods were created with natural daylight supplemented with high-pressure sodium lamps positioned above filters. Viola grown under the FR filter never reached 100% flowering within 8 weeks, and visible bud appearance was delayed by at least 17 days compared to all other filters. The R and B filters enhanced peduncle length by at least 25% compared to the C or FR filters. In Pisum, average internode length was 2.2, 2.9, 3.4, and 3.7 cm under the FR, C, B, and R filters, respectively, all statistically different. Fresh and dry shoot weights were similar under the C and FR filters but were at least 35% greater under the B filter and 35% lower under the R filter.

The effect of photoperiod and temperature on the first crop and ratoon growth of Pennisetum purpureum Schum

1978 ◽  
Vol 29 (5) ◽  
pp. 941 ◽  
Author(s):  
R Ferraris
Keyword(s):  
Dry Matter ◽  
Stem Elongation ◽  
Main Stem ◽  
Pennisetum Purpureum ◽  
Short Day ◽  
Long Day ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Higher Temperature ◽  
Leaf Appearance

Elephant grass (Pennisetum purpureum Schum.) was grown in phytotron cabinets for 60 days at 30/25° or 21/16°C (daylnight) in either 8 or 16 hr photoperiods. During the juvenile phase the higher temperature increased the leaf appearance rate, tillering rate and main stem elongation rate. Once plants in the 8 hr photoperiod became reproductive, the stem elongation, tillering rate and leaf appearance rate increased. The higher temperature continued to stimulate development. At harvest at 60 days plants grown at 30/25° had higher leaf, stem and total dry matter yields, a greater leaf area but lower carbohydrate content in the stubble. The 16 hr photoperiod produced higher dry matter yields at harvest than the 8 hr photoperiod. A comparison pot experiment grown in short day and long day photoperiods under field conditions in north Queensland produced similar findings to the phytotron experiment. After harvest, stubbles were ratooned into either short day (8 hr) or long day (16 hr) photoperiods, the temperature difference being maintained. Leaf number per main stem and main stem elongation were similar to those of the first crop, but more tillers and higher yields were produced in the ratoon crop. Temperature and photoperiod effects were similar in both crops. It was concluded that low temperatures rather than reduced photoperiod would be the greatest limitation to the adaptation of the species as an industrial or forage crop where yearround production is required.

scholarly journals Influence of Photoselective Films and Growing Season on Stem Growth and Flowering of Six Plant Species

2003 ◽  
Vol 128 (4) ◽  
pp. 486-491 ◽  
Author(s):  
Teresa A. Cerny ◽  
James E. Faust ◽  
Desmond R. Layne ◽  
Nihal C. Rajapakse
Keyword(s):  
Plant Species ◽  
Light Transmission ◽  
Stem Elongation ◽  
Broad Band ◽  
Flowering Plant ◽  
Photon Flux ◽  
Light Sources ◽  
Long Day ◽  
Control Film ◽  
Long Day Plants

Growth chambers constructed of photoselective plastic films were used to investigate light quality effects on flowering and stem elongation of six flowering plant species under strongly inductive and weakly inductive photoperiods. Three films were used: a clear control film, a far red (FR) light absorbing (AFR) film and a red (R) light absorbing (AR) film. The AFR and AR films intercepted FR (700 to 800 nm) and R (600 to 700 nm) wavelengths with maximum interception at 730 and 690 nm, respectively. The phytochrome photoequilibrium estimates of transmitted light for the control, AFR, and AR films were 0.71, 0.77, and 0.67. The broad band R:FR ratios were 1.05, 1.51, and 0.77, respectively. The photosynthetic photon flux was adjusted with neutral density filters to provide similar light transmission among chambers. Zinnia elegans Jacq., Dendranthema×grandiflorum Kitam. (chrysanthemum), Cosmos bipinnatus Cav., and Petunia×hybrida Vilm.-Andr. plants grown under the AFR film were shorter than control plants. The AFR film had no effect on height of Antirrhinum majus L. (snapdragon) or Rosa×hybrida (miniature rose). Anthesis of zinnia, chrysanthemum, cosmos (short-day plants), and miniature rose (day-neutral plant) was not influenced by the AFR films. Anthesis of petunia and snapdragon (long-day plants) was delayed up to 13 days by AFR films under weakly inductive photoperiods. In petunia, initiation and development of floral structures were not affected by the AFR films during strongly inductive photoperiods. However, during weakly inductive photoperiods, initiation of the floral primordia was significantly delayed and overall development of the floral meristem was slower than control plants indicating that the AFR films could increase the production time if long-day plants were produced off-season. Daylength extension with electric light sources could overcome this delay in anthesis yet achieve the benefit of AFR films for height reduction without the use of chemical growth regulators.

Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Stem Elongation ◽  
Tree Height ◽  
Shoot Elongation ◽  
Main Stem ◽  
Tree Age ◽  
Precommercial Thinning ◽  
Two Factors ◽  
Artificial Inoculations

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

EFFECTS OF BLUE AND RED LIGHT ON STEM ELONGATION AND FLOWERING OF TOMATO SEEDLINGS

2012 ◽  
pp. 261-266 ◽  
Author(s):  
K. Nanya ◽  
Y. Ishigami ◽  
S. Hikosaka ◽  
E. Goto
Keyword(s):  
Stem Elongation ◽  
Red Light ◽  
Tomato Seedlings

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 Gibberellic acid flower formation and stem elongation in Silene armeria.

1973 ◽  
Vol 21 (4) ◽  
pp. 245-255
Author(s):  
S.J. Wellensiek
Keyword(s):  
Gibberellic Acid ◽  
Stem Elongation ◽  
Flowering Plants ◽  
Plant Age ◽  
Flower Formation ◽  
High Concentration ◽  
Short Day ◽  
Long Day ◽  
Silene Armeria

Several selected S. armeria lines differing in their reaction to GA3 were treated with GA3 at various concentrations under short-day (SD) or long-day conditions. With SD treatment one application of GA3 at high concentration (10 000 p.p.m. or greater) induced flower formation in certain lines. Stem elongation increased with GA3 concentration and with plant age and was much greater on flowering plants than on non-flowering ones. [For previous related work see HcA 41, 4400.]. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Tagesperiodische antagonistische Schwankungen der Blauviolett- und Gelbrot-Empfindlichkeit als Grundlage der photoperiodischen Diapause-Induktion bei Pieris brassicae

1960 ◽  
Vol 15 (4) ◽  
pp. 205-213 ◽  
Author(s):  
Erwin Bünning ◽  
Gabriele Joerrens
Keyword(s):  
Dark Period ◽  
Red Light ◽  
Pieris Brassicae ◽  
Light Period ◽  
Measuring Process ◽  
The Third ◽  
Long Day ◽  
Critical Daylength ◽  
Qualitative Responses ◽  
Short Days

In Pieris brassicae, diapause is inhibited if long-day conditions are imposed during and immediately after the third molting. The critical daylength is approximately 14 hours. Under short-day conditions with a main light period of 6 or 12 hours’ duration, supplementary light given in the period from 14 to 16 hours after the beginning of the main light period will inhibit diapause. In contrast to this effect of late exposures to light, light given from 1 to 12 hours after the beginning of the main light period promotes diapause. Experiments with extremely long light periods (10—35 hours), but always with a dark period of 10 hours, show that these diurnal fluctuations in quantitative and qualitative responses to light can continue endogenously for several days. Thus, this time-measuring process operates through the mechanism of endogenous diurnal oscillations in just the same way as do photoperiodic reactions in plants.The inhibition of diapause by light in the second half of the diurnal oscillation (under long days or by light interruptions in the dark period) and the promotion by light in the first half (under short days) occur only with light of short wavelengths: ultraviolet, violet, and blue up to about 550 mμ. Yellow and red light act in the opposite fashion, giving diapause inhibition in the first half of the cycle and promotion in the second half. In white light the violet reaction predominates, so that diapause is promoted by short days and inhibited by long days.

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