scholarly journals The Effect of Daily Light Integral on Floral Initiation of Pelargonium ×domesticum L.H. Bailey

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 529-532
Author(s):  
Marietta M. Loehrlein ◽  
Richard Craig
Keyword(s):  
Morphological Changes ◽  
Genotypic Variation ◽  
Floral Initiation ◽  
Daily Light Integral ◽  
Growth Chambers ◽  
Light Integral ◽  
Chronological Time

Nine cultivars of Pelargonium ×domesticum L.H. Bailey were evaluated for the effect of daily light integral on floral initiation. Plants were grown at four daily light integrals: 5, 10, 15, or 20 mol·m-2·d-1 for a 16-hour photoperiod in environmental growth chambers at constant 15.5 °C. Meristems were examined at 50 mol·m-2 intervals for morphological changes associated with floral initiation. Two phenotypes were identified, cultivars with an association between floral initiation and cumulative irradiance and those with association between floral initiation and chronological time. Genotypic variation was observed among the irradiance-associated phenotypes.

scholarly journals 541 Floral Initiation of Regal Pelargonium Grown at Varying Daily Light Integrals

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 539B-539
Author(s):  
Marietta Loehrlein ◽  
Richard Craig
Keyword(s):  
Morphological Changes ◽  
Genotypic Variation ◽  
Floral Initiation ◽  
Daily Light Integral ◽  
Growth Chambers ◽  
Light Integral ◽  
Chronological Time

Nine cultivars of Pelargonium × domesticum representing three germplasm sources were evaluated for the effect of daily light integral on floral initiation. Plants were grown at four daily light integrals: 5, 10, 15, or 20 mols/day for a 16-h photoperiod in environmental growth chambers at constant 15.5 °C. Meristems were examined at 50-mol intervals (0 to 350 mols) for morphological changes associated with floral initiation. Two phenotypes were identified, cultivars with an association between floral initiation and irradiance and those with association between floral initiation and chronological time. Genotypic variation was observed among the cultivars of each phenotype.

scholarly journals Temperature and Photoperiod Influence Flowering and Morphology of Four Petunia spp.

HortScience ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 365-368 ◽  
Author(s):  
Ryan M. Warner
Keyword(s):  
Base Temperature ◽  
Optimal Temperature ◽  
Flower Bud ◽  
Breeding Programs ◽  
Node Number ◽  
Daily Light Integral ◽  
Long Day ◽  
Light Integral ◽  
Short Days ◽  
Petunia Axillaris

Flowering and morphology of four Petunia Juss. spp. [P. axillaris (Lam.) Britton et al., P. exserta Stehmann, P. integrifolia (Hook.) Schinz & Thell., and P. ×hybrida Vilm.] were evaluated in response to photoperiod and temperature. Photoperiod responses were evaluated under 9-h short days (SD), 9-h photoperiod plus 4-h night-interruption lighting (NI), or a 16-h photoperiod supplemented with high-pressure sodium lamps (16-h HPS). All species flowered earlier under NI than SD and were classified as facultative (quantitative) long-day plants. Increasing the daily light integral within long-day treatments increased flower bud number for P. axillaris only. In a second experiment, crop timing and quality were evaluated in the temperature range of 14 to 26 °C under 16-h HPS. The rate of progress toward flowering for each species increased as temperature increased from 14 to 26 °C, suggesting the optimal temperature for development is at least 26 °C. The calculated base temperature for progress to flowering varied from 0.1 °C for P. exserta to 5.3 °C for P. integrifolia. Flowering of P. axillaris and P. integrifolia was delayed developmentally (i.e., increased node number below the first flower) at 14 °C and 17 °C or less, respectively, compared with higher temperatures. Petunia axillaris and P. integrifolia flower bud numbers decreased as temperature increased, whereas P. ×hybrida flower bud number was similar at all temperatures. The differences in crop timing and quality traits observed for these species suggest that they may be useful sources of variability for petunia breeding programs.

scholarly journals Effects of season, altitude and daylength on floral initiation of two contrasting genotypes of Trifolium repens L.

1986 ◽  
Vol 106 (1) ◽  
pp. 149-154 ◽  
Author(s):  
F. Von Sury ◽  
J. Nösberger
Keyword(s):  
Low Temperature ◽  
Seed Production ◽  
Floral Initiation ◽  
Cool Season ◽  
Production Potential ◽  
Low Latitude ◽  
Specific Effects ◽  
Trifolium Repens L ◽  
Growth Chambers ◽  
Main Factors

SUMMARYThe effects of season and altitude on floral initiation of two Trifolium repena L. cultivars, Haifa and California Ladino, were tested in the area of Ayacucho, Peru (2730 m, 13° S), with regard to their seed production potential. Specific effects of daylength at a constant temperature (20 °C) were examined in growth chambers.In Ayacucho, the proportion of inflorescence-bearing nodes was found to be lowest between December and June (Haifa 10–20%, Ladino 0–10%) and highest in August (Haifa 30%) and September–October (Ladino 15%). Late in the cool season, floral initiation of Ladino, but not that of Haifa, increased strongly at a high altitude (3250 m). In growth chambers, Haifa initiated few inflorescences and Ladino none in a 10 h daylength. In 16 h, the floral initiation of Haifa was very limited but Ladino formed many inflorescences. Floral initiation of Haifa was most pronounced and lasted longest after a daylength shift from 10 to 13 h.It is concluded that seasonal and altitudinal variations in low temperature were the main factors influencing floral initiation in the region of Ayacucho. Haifa is considered to be an intermediate-day plant, suited for seed production in the region because of its marked and early flowering. Ladino was classified as a quantitative longday plant, unsuitable for seed production at this low latitude because of its retarded floral response to low temperature.

scholarly journals Effects of Daily Light Integral and LED Spectrum on Growth and Nutritional Quality of Hydroponic Spinach

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1082 ◽  
Author(s):  
Wei Gao ◽  
Dongxian He ◽  
Fang Ji ◽  
Sen Zhang ◽  
Jianfeng Zheng
Keyword(s):  
Vitamin C ◽  
Blue Light ◽  
Nutritional Quality ◽  
Red Light ◽  
Nitrate Content ◽  
Energy Yield ◽  
Daily Light Integral ◽  
Fluorescent Lamps ◽  
Plant Factory ◽  
Light Integral

To achieve clean and high-quality spinach production, the effects of daily light integral (DLI) and light spectrum on growth, nutritional quality, and energy yield of hydroponic spinach (Spinacia oleracea L.) were investigated in a closed plant factory under light-emitting diode (LED) lighting. The hydroponic spinach plants were grown under 16 combinations of four levels of DLI (11.5, 14.4, 17.3, and 20.2 mol m−2 day−1) with four light spectra: LED lamps with ratio of red light to blue light (R:B ratio) of 0.9, 1.2, and 2.2 and fluorescent lamps with R:B ratio of 1.8 as control. The results show that total fresh and dry weights, energy yield, and light energy use efficiency (LUE) of harvested spinach were higher under D17.3-L1.2 treatment compared to other treatments. The higher net photosynthetic rates were shown at DLI of 17.3 mol m−2 day−1 regardless of light quality. Higher vitamin C contents of spinach in all LED treatments were obtained compared with the control. L1.2 treatments with higher fraction of blue light led to more vitamin C content, lower nitrate content, and higher LUE independent of DLI. L2.2 treatment with more fraction of red light was beneficial to reduce oxalate accumulation. Power consumption based on increased total fresh weight under LED lamps with R:B ratio of 1.2 in different DLIs was over 38% lower than that under the fluorescent lamps and 1.73 kWh per 100 g FW at DLI of 17.3 mol m−2 day−1. In conclusion, lighting environment in DLI of 17.3 mol m−2 day−1 using LED lamps with R:B ratio of 1.2 is suggested for the design of a LED plant factory for hydroponic spinach production.

Comparative Performance and Daily Light Integral Requirements of Warm-Season Turfgrasses in Different Seasons

Crop Science ◽  
2017 ◽  
Vol 57 (4) ◽  
pp. 2273-2282 ◽  
Author(s):  
Jing Zhang ◽  
Brian Glenn ◽  
J. Bryan Unruh ◽  
Jason Kruse ◽  
Kevin Kenworthy ◽  
...  
Keyword(s):  
Warm Season ◽  
Comparative Performance ◽  
Daily Light Integral ◽  
Different Seasons ◽  
Light Integral

STRATEGIES FOR A CONSTANT DAILY LIGHT INTEGRAL IN GREENHOUSES

2005 ◽  
pp. 117-124 ◽  
Author(s):  
I. Seginer ◽  
I. Ioslovich ◽  
L.D. Albright
Keyword(s):  
Daily Light Integral ◽  
Light Integral

scholarly journals Underwater Light Characteristics of Turbid Coral Reefs of the Inner Central Great Barrier Reef

2021 ◽  
Vol 8 ◽  
Author(s):  
Ross Jones ◽  
Mari-Carmen Pineda ◽  
Heidi M. Luter ◽  
Rebecca Fisher ◽  
David Francis ◽  
...  
Keyword(s):  
Coral Reef ◽  
Turbid Water ◽  
Light Reduction ◽  
Daily Light Integral ◽  
Spectral Changes ◽  
Underwater Light ◽  
Spectral Shifts ◽  
Reef Communities ◽  
Light Integral ◽  
Turbid Zone

Hyper-spectral and multi-spectral light sensors were used to examine the effects of elevated suspended sediment concentration (SSC) on the quantity and quality (spectral changes) of underwater downwelling irradiance in the turbid-zone coral reef communities of the inner, central Great Barrier Reef (GBR). Under elevated SSCs the shorter blue wavelengths were preferentially attenuated which together with attenuation of longer red wavelengths by pure water shifted the peak in the underwater irradiance spectrum ~100 nm to the less photosynthetically useful green-yellow waveband (peaking at ~575 nm). The spectral changes were attributed to mineral and detrital content of the terrestrially-derived coastal sediments as opposed to chromophoric (coloured) dissolved organic matter (CDOM). A simple blue to green (B/G, λ455:555 nm) ratio was shown to be useful in detecting sediment (turbidity) related decreases in underwater light as opposed to those associated with clouds which acted as neutral density filters. From a series of vertical profiles through turbid water, a simple, multiple component empirical optical model was developed that could accurately predict the light reduction and associated spectral changes as a function of SSC and water depth for a turbid-zone coral reef community of the inner GBR. The relationship was used to assess the response of a light sensitive coral, Pocillopora verrucosa in a 28-d exposure laboratory-based exposure study to a daily light integral of 1 or 6 mol quanta m2. PAR with either a broad spectrum or a green-yellow shifted spectrum. Light reduction resulted in a loss of the algal symbionts (zooxanthellae) of the corals (bleaching) and significant reduction in growth and lipid content. The 6 mol quanta m2 d−1 PAR treatment with a green-yellow spectrum also resulted in a reduction in the algal density, Chl a content per cm2, lipids and growth compared to the same PAR daily light integral under a broad spectrum. Turbid zone coral reef communities are naturally light limited and given the frequency of sediment resuspension events that occur, spectral shifts are a common and previously unrecognised circumstance. Dedicated underwater light monitoring programs and further assessment of the spectral shifts by suspended sediments are essential for contextualising and further understanding the risk of enhanced sediment run-off to the inshore turbid water communities.

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