scholarly journals Differing Vernalization Responses of Veronica spicata ‘Red Fox’ and Laurentia axillaris

2007 ◽  
Vol 132 (6) ◽  
pp. 751-757 ◽  
Author(s):  
Beth A. Fausey ◽  
Arthur C. Cameron
Keyword(s):  
Red Fox ◽  
Relative Effectiveness ◽  
Temperature Response ◽  
Response Curves ◽  
Node Number ◽  
Herbaceous Perennials ◽  
Daily Light Integral ◽  
Cold Requirement ◽  
Light Integral ◽  
Extended Exposure

Many polycarpic herbaceous perennials are known to have a cold-requirement for flowering. To determine the range and relative effectiveness of vernalization temperatures for flower induction, clonally propagated plants of veronica (Veronica spicata L.) ‘Red Fox’ and laurentia [Laurentia axillaris (Lindl.) E. Wimm.] were exposed to temperatures from −2.5 to 20 °C at 2.5 °C increments for 0, 2, 4, 6, or 8 weeks (veronica ‘Red Fox’) and 0, 2.5, 5, 7.5, 10, 12.5, or 15 weeks (laurentia). After treatments, growth and flowering were monitored in a glass greenhouse set at 20 °C with an average daily light integral of ≈5 mol·m−2·d−1. Both veronica ‘Red Fox’ and laurentia exhibited obligate vernalization requirements for flowering, but the temperature–response curves were distinctly different. A minimum of 4 weeks at −2.5 and 0 °C, 6 weeks at 2.5 °C, and 8 weeks at 5 and 7.5 °C was required for complete (100%) flowering of veronica ‘Red Fox’, while a minimum of 5 weeks at 5 to 10 °C, 7.5 weeks at 12.5 °C, and 10 weeks at 2.5 °C were required for complete flowering of laurentia. For veronica ‘Red Fox’, node number under each flower and flower timing were relatively fixed following up to 8 weeks at each temperature, although these values generally decreased at each temperature with extended exposure for laurentia. Based on percent flowering and percentage of lateral nodes flowering, vernalization of veronica ‘Red Fox’ was most effective at 0 and −2.5 °C, while based on percent flowering and flower number, vernalization of laurentia was most effective at 5 to 10 °C.

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 Prevernalization Daily Light Integral and Vernalization Temperature Influences Flowering of Herbaceous Perennials

HortScience ◽  
2002 ◽  
Vol 37 (7) ◽  
pp. 1028-1031 ◽  
Author(s):  
Genhua Niu ◽  
Royal Heins ◽  
Arthur Cameron ◽  
William Carlson
Keyword(s):  
Plant Height ◽  
Flower Development ◽  
Flower Number ◽  
Lavandula Angustifolia ◽  
Herbaceous Perennials ◽  
Daily Light Integral ◽  
Delayed Flowering ◽  
Light Integral

The influence of daily light integral (DLI) before vernalization and vernalization temperature and duration on growth and flower development was determined for seed-propagated perennials Aquilegia ×hybrida Sims `Remembrance', Coreopsis grandiflora Hogg ex Sweet `Sunray', and Lavandula angustifolia Mill. `Hidcote Blue'. Seedlings were grown under two DLIs (4 or 14 mol·m-2·d-l) for 5 weeks before being vernalized at -2.5, 0, 2.5, or 5 °C for 2,4,5, or 8 weeks. `Remembrance' and `Sunray' plants were vernalized in the dark, while `Hidcote Blue' plants were vernalized in light at 5 to 10 μmol·m-2·s-l for 9 hourslday. After vernalization, plants were forced under a 16-h photoperiod in the greenhouse at 20±2 °C. `Remembrance' plants flowered uniformly when vernalized at 0 to 2.5 °C for 2 weeks or longer, and flower number, plant height, time to visible bud or to flower were generally not influenced by vernalization temperature or duration. No `Sunray' plants flowered without vernalization, and only a low percentage flowered with 4-week vernalization. Compared with low DLI, a 14 mol·m-2·d-1 before vernalization delayed flowering by 7 to 20 days in `Remembrance', but there were no substantial differences in flowering characteristics of `Sunray'. `Hidcote Blue' plants were best vernalized in the light at 5 °C for 8 weeks to obtain rapid and uniform flowering and the highest number of inflorescences. Flowering and survival percentages of `Hidcote Blue' were much lower for plants at 14 mol·m-2·d-l DLI compared to 4 mol·m-2·d-1.

scholarly journals Enabling Year-round Cultivation in the Nordics-Agrivoltaics and Adaptive LED Lighting Control of Daily Light Integral

Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1255
Author(s):  
Marco Hernandez Velasco
Keyword(s):  
Sole Source ◽  
Light Transmittance ◽  
Lighting Control ◽  
Potted Plants ◽  
Herbaceous Perennials ◽  
Daily Light Integral ◽  
Monthly Average ◽  
Wall Structures ◽  
Supplementary Lighting ◽  
Light Integral

High efficacy LED lamps combined with adaptive lighting control and greenhouse integrated photovoltaics (PV) could enable the concept of year-round cultivation. This concept can be especially useful for increasing the production in the Nordic countries of crops like herbaceous perennials, forest seedlings, and other potted plants not native of the region, which are grown more than one season in this harsh climate. Meteorological satellite data of this region was analyzed in a parametric study to evaluate the potential of these technologies. The generated maps showed monthly average temperatures fluctuating from −20 °C to 20 °C throughout the year. The natural photoperiod and light intensity also changed drastically, resulting in monthly average daily light integral (DLI) levels ranging from 45–50 mol·m−2·d−1 in summer and contrasting with 0–5 mol·m−2·d−1 during winter. To compensate, growth room cultivation that is independent of outdoor conditions could be used in winter. Depending on the efficacy of the lamps, the electricity required for sole-source lighting at an intensity of 300 µmol·m−2·s−1 for 16 h would be between 1.4 and 2.4 kWh·m−2·d−1. Greenhouses with supplementary lighting could help start the cultivation earlier in spring and extend it further into autumn. The energy required for lighting highly depends on several factors such as the natural light transmittance, the light threshold settings, and the lighting control protocol, resulting in electric demands between 0.6 and 2.4 kWh·m−2·d−1. Integrating PV on the roof or wall structures of the greenhouse could offset some of this electricity, with specific energy yields ranging from 400 to 1120 kWh·kW−1·yr−1 depending on the region and system design.

scholarly journals Comparing Flowering Responses of Long-day Plants under Incandescent and Two Commercial Light-emitting Diode Lamps

2014 ◽  
Vol 24 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Fumiko Kohyama ◽  
Catherine Whitman ◽  
Erik S. Runkle
Keyword(s):  
Plant Height ◽  
Energy Efficient ◽  
Light Emitting Diode ◽  
Node Number ◽  
Light Emitting ◽  
Daily Light Integral ◽  
Low Intensity ◽  
Long Day ◽  
Long Day Plants ◽  
Light Integral

When the natural daylength is short, commercial growers of ornamental long-day plants (LDP) often provide low-intensity lighting to more rapidly and uniformly induce flowering. Incandescent (INC) lamps have been traditionally used for photoperiodic lighting because their spectrum, rich in red [R (600 to 700 nm)] and far-red [FR (700 to 800 nm)] light, is effective and they are inexpensive to purchase and install. Light-emitting diodes (LEDs) are much more energy efficient, can emit wavelengths of light that specifically regulate flowering, and last at least 20 times longer. We investigated the efficacy of two new commercial LED products developed for flowering applications on the LDP ageratum (Ageratum houstonianum), calibrachoa (Calibrachoa ×hybrida), two cultivars of dianthus (Dianthus chinensis), and two cultivars of petunia (Petunia ×hybrida). Plants were grown under a 9-hour short day without or with a 4-hour night interruption (NI) delivered by one of three lamp types: INC lamps (R:FR = 0.59), LED lamps with R and white (W) diodes [R + W (R:FR = 53.35)], and LED lamps with R, W, and FR diodes [R + W + FR (R:FR = 0.67)]. The experiment was performed twice, both at a constant 20 °C, but the photosynthetic daily light integral (DLI) during the second replicate (Rep. II) was twice that in the first (Rep. I). In all crops and in both experimental replicates, time to flower, flower or inflorescence and node number, and plant height were similar under the R + W + FR LEDs and the INC lamps. However, in Rep. I, both petunia cultivars developed more nodes and flowering was delayed under the R + W LEDs compared with the INC or R + W + FR LEDs. In Rep. II, petunia flowering time and node number were similar under the three NI treatments. Plant height of both dianthus cultivars was generally shorter under the NI treatment without FR light (R + W LEDs). These results indicate that when the DLI is low (e.g., ≤6 mol·m−2·d−1), FR light is required in NI lighting for the most rapid flowering of some but not all LDP; under a higher DLI, the flowering response to FR light in NI lighting is apparently diminished.

scholarly journals Photosynthetic Daily Light Integral during Propagation of Tecoma stans Influences Seedling Rooting and Growth

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 282-286 ◽  
Author(s):  
Ariana P. Torres ◽  
Roberto G. Lopez
Keyword(s):  
Leaf Area ◽  
Dry Mass ◽  
Early Spring ◽  
Node Number ◽  
Tropical Plants ◽  
Daily Light Integral ◽  
Tropical Plant ◽  
Increasing Demand ◽  
Seed Propagation ◽  
Light Integral

Current market trends indicate an increasing demand for unique and exotic flowering crops, including tropical plants. Tecoma stans (L. Juss. Kunth) ‘Mayan Gold’ is a tropical plant that was selected as a potential new greenhouse crop for its physical appearance and drought and heat tolerance. However, in winter and early spring, when propagation occurs, outdoor photosynthetic daily light integral (DLI) can be relatively low. The objective of this study was to quantify the effects of DLI during propagation of Tecoma and to determine optimum DLI levels for seed propagation. Seeds were propagated under 13 mean DLIs ranging from 0.75 to 25.2 mol·m−2·d−1 created by the combination of high-pressure sodium lamps (HPS) and fixed woven shadecloths of varying densities. Thirty-five days after sowing, height, stem diameter, node number, relative leaf chlorophyll content, leaf fresh weight, leaf number, total leaf area, individual leaf area, leaf area ratio, shoot and root dry mass increased as DLI increased. Average internode elongation and specific leaf area decreased at a quadratic and linear rate, respectively, as DLI increased from 0.75 to 25.2 mol·m−2·d−1. These experiments indicate that high-quality Tecoma seedlings were obtained when DLI was 14 to 16 mol·m−2·d−1 during propagation.

scholarly journals Daily Light Integral Affects Flowering and Quality of Greenhouse-grown Achillea, Gaura, and Lavandula

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Beth A. Fausey ◽  
Royal D. Heins ◽  
Arthur C. Cameron
Keyword(s):  
Growth And Development ◽  
Visual Quality ◽  
Light Level ◽  
Dry Mass ◽  
Ambient Light ◽  
Herbaceous Perennials ◽  
Daily Light Integral ◽  
Light Integral ◽  
Prostrate Growth

The growth and development of Achillea ×millefolium L. `Red Velvet', Gaura lindheimeri Engelm. & Gray `Siskiyou Pink' and Lavandula angustifolia Mill. `Hidcote Blue' were evaluated under average daily light integrals (DLIs) of 5 to 20 mol·m-2·d-1. Plants were grown in a 22 ± 2 °C glass greenhouse with a 16-h photoperiod under four light environments: 50% shading of ambient light plus PPF of 100 μmol·m-2·s-1 (L1); ambient light plus PPF of 20 μmol·m-2·s-1 (L2); ambient light plus PPF of 100 μmol·m-2·s-1 (L3); and ambient light plus PPF of 150 μmol·m-2·s-1 (L4). Between 5 to 20 mol·m-2·d-1, DLI did not limit flowering and had little effect on timing in these studies. Hence, the minimum DLI required for flowering of Achillea, Gaura and Lavandula must be <5 mol·m-2·d-1, the lowest light level tested. However, all species exhibited prostrate growth with weakened stems when grown at a DLI of about 10 mol·m-2·d-1. Visual quality and shoot dry mass of Achillea, Gaura and Lavandula linearly increased as DLI increased from 5 to 20 mol·m-2·d-1 and there was no evidence that these responses to light were beginning to decline. While 10 mol·m-2·d-1 has been suggested as an adequate DLI, these results suggest that 15 to 20 mol·m-2·d-1 should be considered a minimum for production of these herbaceous perennials when grown at about 22 °C.

scholarly journals Differing Vernalization Responses of Laurentia axillaris and Veronica spicata `Red Fox': Evidence for Two Thermometers?

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 878D-878
Author(s):  
Beth A. Fausey ◽  
Arthur C. Cameron*
Keyword(s):  
Red Fox ◽  
Minimum Duration ◽  
Node Number ◽  
Herbaceous Perennials ◽  
Lateral Shoots ◽  
Effective Temperatures ◽  
Specific Species

Many herbaceous perennials require vernalization although effective temperatures (ET) and durations for specific species are largely unknown. To investigate vernalization of Laurentia axillaris (Lindl.) E. Wimm. and Veronica spicata L. `Red Fox', vegetative plugs were stored at -2.5, 0.0, 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 °C for 0 to 15 weeks (Laurentia) or 0 to 8 weeks (Veronica). Following storage, plugs were grown in a 20 °C glass greenhouse with a 16-h photoperiod. Laurentia plugs did not survive storage at -2.5 or 0 °C. Survival varied for plants stored at 2.5 °C, and some plants flowered. ET and the minimum duration for 100% flowering of Laurentia were: 5 weeks at 5 to 10 °C and 10 weeks at 12.5 °C. Time to first visible bud and node number below first visible bud decreased with increasing duration at ET. Veronica plugs survived storage at all temperatures. 100% flowering occurred when plants were vernalized at -2.5 and 0 °C for 4 or more weeks, at 2.5 and 5.0 °C for 6 or more weeks, and at 7.5 °C for 8 weeks. Incomplete vernalization (19 to 93%) occurred at temperatures of 2.5 °C for 4 weeks, 5 °C for 4 or 6 weeks, 7.5 °C for 6 weeks and at 10 °C for 6 or 8 weeks. Vernalization did not occur above 10 °C or following 2 weeks storage at any temperature. The percentage of reproductive lateral shoots increased while node number below the inflorescence remained constant or decreased with increasing storage at ET. The results indicate distinct vernalization optima for the two species; Laurentia 5 to 10 °C, and Veronica -2.5 to 0 °C. These differences provide evidence that separate “thermometers” may be involved in vernalization perception.

ÜBER DIE ANTAGONISTISCHE WIRKUNG VON TRIJODTHYRONIN UND PROGESTERON AUF DEN PREDNISOLONEFFEKT AM EPIPHYSENKNORPEL (PRÜFUNG DER REISSFESTIGKEIT)

1963 ◽  
Vol 42 (1) ◽  
pp. 29-38 ◽  
Author(s):  
L. Ther ◽  
H. Schramm ◽  
G. Vogel
Keyword(s):  
Tensile Strength ◽  
Dose Response ◽  
Single Injection ◽  
Relative Effectiveness ◽  
Prednisolone Acetate ◽  
Response Curves ◽  
Deoxycorticosterone Acetate ◽  
Weight Range ◽  
Diuretic Action ◽  
Maximal Load

ABSTRACT Longitudinal tension exerted on a killed rat's femur results always in rupture on the same place viz: the distal epiphyseal line. The power required to produce this effect can be measured with a simple dynamometer. The tensile strength increases with advancing age and during exsiccation (thirst). In untreated rats (weight range 100–120 g) this value amounts to about 1.5–1.8 kg. Tensile strength of the femoral epiphyseal line may be influenced by hormones. Corticosteroids such as prednisolone acetate and cortisol acetate increase the level of maximal load to more than 2.0 kg. In general the effect of a single injection reaches a climax after 48 hours. Dose-response-curves can be established and relative effectiveness may be gathered therefrom. Deoxycorticosterone acetate likewise increases tensile strength in spite of the fact that contrary to prednisolone exhibiting diuretic action this compound has a water retaining effect. Triiodothyronine and progesterone when given alone produce a slight decrease in tensile strength. The effect of prednisolone when given simultaneously with one of these two compounds is antagonized: this phenomenon is more pronounced in the case of triiodothyronine.

scholarly journals Differences in Leaf Temperature between Lianas and Trees in the Neotropical Canopy

2018 ◽  
Author(s):  
J. Antonio Guzmán Q. ◽  
G. Arturo Sánchez-Azofeifa ◽  
Benoit Rivard
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Temperature Response ◽  
Life Forms ◽  
Leaf Temperature ◽  
Response Curves ◽  
Tropical Environments ◽  
Host Trees ◽  
Temperature Responses ◽  
Photosynthesis And Respiration

Leaf temperature (Tleaf) influences photosynthesis and respiration. Currently, there is a growing interest on including lianas in productivity models due to their increasing abundance, and their detrimental effects on net primary productivity in tropical environments. Therefore, understanding the differences of Tleaf between lianas and trees is important for future of forest on whole ecosystem productivity. Here we determined the displayed leaf temperature (Td= Tleaf &ndash; ambient temperature) of several species of lianas and their host trees during ENSO and non-ENSO years to evaluate if the presence of lianas affects the Td of their host trees, and if leaves of lianas and their host trees exhibit differences in Td. Our results suggest that close to midday, the presence of lianas does not affect the Td of their host trees; however, lianas tend to have higher values of Td than their hosts across seasons, in both ENSO and non-ENSO years. Although lianas and trees tend to have similar physiological-temperature responses, differences in Td could lead to significant differences in rates of photosynthesis and respiration based temperature response curves. Future models should thus consider differences in leaf temperature between these life forms to achieve robust predictions of productivity.

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