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 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 Photosynthetic Daily Light Integral during Propagation Influences Rooting and Growth of Cuttings and Subsequent Development of New Guinea Impatiens and Petunia

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2052-2059 ◽  
Author(s):  
Roberto G. Lopez ◽  
Erik S. Runkle
Keyword(s):  
Growth And Development ◽  
Subsequent Development ◽  
New Guinea ◽  
Separate Experiment ◽  
Subsequent Growth ◽  
Shoot Height ◽  
Daily Light Integral ◽  
Subsequent Time ◽  
New Guinea Impatiens ◽  
Light Integral

A majority of commercial propagation of herbaceous ornamental cuttings occurs during the winter when the photosynthetic daily light integral (DLI) is relatively low. We quantified how the mean DLI influenced rooting and subsequent growth and development of two popular vegetatively propagated species, New Guinea impatiens (Impatiens hawkeri Bull.) and petunia (Petunia ×hybrida hort. Vilm.-Andr.). Three cultivars of each species were propagated under a mean DLI ranging from 1.2 to 10.7 mol·m−2·d−1. Cuttings were rooted in a controlled greenhouse environment maintained at 24 to 25 °C with overhead mist, a vapor-pressure deficit of 0.3 kPa, and a 12-h photoperiod. Rooting and growth evaluations of cuttings were made after 8 to 16 d. In a separate experiment, rooted cuttings under DLI treatments were then transplanted into 10-cm containers and grown in a common greenhouse at 21 ± 2 °C under a 16-h photoperiod to identify any residual effects on subsequent growth and development. In both species, rooting, biomass accumulation, and quality of cuttings increased and subsequent time to flower generally decreased as mean propagation DLI increased. For example, root number of petunia ‘Tiny Tunia Violet Ice’ after 16 days of propagation increased from 17 to 40 as the propagation DLI increased from 1.2 to 7.5 mol·m−2·d−1. In addition, cutting shoot height decreased from 6.3 to 4.5 cm, and root and shoot dry biomass of cuttings harvested after 16 days of propagation increased by 737% and 106%, respectively. Subsequent time to flower for ‘Tiny Tunia Violet Ice’ from the beginning of propagation decreased from 50 to 29 days as propagation DLI increased from 1.4 to 10.7 mol·m−2·d−1 regardless of the DLI provided after propagation. In New Guinea impatiens ‘Harmony White’, root and shoot dry weight of cuttings increased by 1038% and 82%, respectively, and subsequent time to flower decreased from 85 to 70 days as the propagation DLI increased from 1.2 to 10.7 mol·m−2·d−1. These experiments quantify the role of the photosynthetic DLI during propagation on the rooting and subsequent growth and development of vegetatively propagated herbaceous ornamental cuttings.

scholarly journals Morphological and Physiological Properties of Greenhouse-Grown Cucumber Seedlings as Influenced by Supplementary Light-Emitting Diodes with Same Daily Light Integral

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 361
Author(s):  
Zhengnan Yan ◽  
Long Wang ◽  
Yifei Wang ◽  
Yangyang Chu ◽  
Duo Lin ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Emitting Diodes ◽  
Root Surface Area ◽  
Light Emitting ◽  
Cucumber Seedlings ◽  
Daily Light Integral ◽  
Physiological Properties ◽  
Light Duration ◽  
Light Integral

Insufficient light in autumn–winter may prolong the production periods and reduce the quality of plug seedlings grown in greenhouses. Additionally, there is no optimal protocol for supplementary light strategies when providing the same amount of light for plug seedling production. This study was conducted to determine the influences of combinations of supplementary light intensity and light duration with the same daily light integral (DLI) on the morphological and physiological properties of cucumber seedlings (Cucumis sativus L. cv. Tianjiao No. 5) grown in a greenhouse. A supplementary light with the same DLI of 6.0 mol m−2 d−1 was applied with the light duration set to 6, 8, 10, or 12 h d−1 provided by light-emitting diodes (LEDs), and cucumber seedlings grown with sunlight only were set as the control. The results indicated that increasing DLI using supplementary light promoted the growth and development of cucumber seedlings over those grown without supplementary light; however, opposite trends were observed in the superoxide dismutase (SOD) and catalase (CAT) activities. Under equal DLI, increasing the supplementary light duration from 6 to 10 h d−1 increased the root surface area (66.8%), shoot dry weight (24.0%), seedling quality index (237.0%), root activity (60.0%), and stem firmness (27.2%) of the cucumber seedlings. The specific leaf area of the cucumber seedlings decreased quadratically with an increase in supplementary light duration, and an opposite trend was exhibited for the stem diameter of the cucumber seedlings. In summary, increased DLI or longer light duration combined with lower light intensity with equal DLI provided by supplementary light in insufficient sunlight seasons improved the quality of the cucumber seedlings through the modification of the root architecture and stem firmness, increasing the mechanical strength of the cucumber seedlings for transplanting.

scholarly journals Quality of pre-sprouted sugarcane seedlings grown on substrates with decomposed babassu palm stem

2021 ◽  
Vol 51 ◽  
Author(s):  
Romário Martins Costa ◽  
Marcos Renan Lima Leite ◽  
Sâmia dos Santos Matos ◽  
Rayssa Carolinne Mouzinho de Sousa ◽  
Raissa Rachel Salustriano da Silva-Matos ◽  
...  
Keyword(s):  
Growth And Development ◽  
Dry Mass ◽  
Quality Parameters ◽  
Point Of View ◽  
Production Costs ◽  
Economic Point ◽  
Babassu Palm ◽  
Number Of Leaves ◽  
The Cost

ABSTRACT The use of pre-sprouted seedlings in the implantation of sugarcane crops not only reduces the establishment period and production costs, but also has other advantages, such as a lesser requirement of propagules (stems) and greater phytosanitary control of the seedlings, when compared to conventional planting. Commercial substrates are also expensive and their use increases the cost of seedlings. This study aimed to evaluate the quality of sugarcane pre-sprouted seedlings grown on substrates with different proportions of decomposed babassu palm stem (DBPS), as well as to recommend the substrate formulation that provides the most favorable environment for the growth and development of sugarcane pre-sprouted seedlings. For preparation of the substrate (S), DBPS and soil were used in the following proportions: S1: 0 % of DBPS + 100 % of soil; S2: 20 % of DBPS + 80 % of soil; S3: 40 % of DBPS + 60 % of soil; S4: 60 % of DBPS + 40 % of soil; S5: 80 % of DBPS + 20 % of soil; S6: 100 % of DBPS + 0 % of soil. The use of S2 and S3 considerably improved the seedling quality parameters, such as sprout diameter and length, number of leaves and total, shoot and root dry mass. However, from an economic point of view, S2 is recommended for use.

scholarly journals Near-infrared Reflective Diffusion Coating Is Beneficial for Asparagus Summer Production in a Simple Plastic Greenhouse

HortScience ◽  
2022 ◽  
Vol 57 (2) ◽  
pp. 257-264
Author(s):  
Wei-Ling Chen ◽  
Chun-Jung Shen
Keyword(s):  
Near Infrared ◽  
Diffusion Coating ◽  
Daily Light Integral ◽  
Yield And Quality ◽  
Use Efficiency ◽  
Microclimatic Conditions ◽  
The Mean ◽  
Central Taiwan ◽  
Light Integral

Asparagus is a potential greenhouse crop, and its production is considerably affected by temperature and light, especially in the summer season. This study investigated the effects of the application of near-infrared (NIR)-reflective diffusion coating on a simple plastic greenhouse on microclimatic conditions, plant response, spear yield, and quality of the asparagus plant in central Taiwan. The results showed that NIR-reflective diffusion coating reduced the mean air temperature inside the greenhouse by 0.3 to 0.9 °C and leaf temperature by 2.3, 2.4, and 2.4 °C at a canopy height of 50, 100, and 50 cm, respectively. Although the accumulated daily light integral (DLI) transmitted in the coated greenhouse exhibited an 18.9% reduction compared with a 16.8% reduction in the noncoated greenhouse, a more uniform spatial light distribution was noted. Therefore, photosynthesis improved in the middle and bottom canopy, and plants could maintain a higher transpiration rate, thus resulting in atmospheric cooling. The average spear yield increased by 31.4% in summer and by 10.1% during the following harvest with a lower crude fiber (CF) content and higher Ca as well as Mg contents. In addition, the number of newly emerged shoots increased by 48.8% after the removal of the mother stalk under coating. NIR-reflective diffusion coating can be used as an energy-saving method for enhancing cooling and improving light use efficiency, thus increasing asparagus production in a greenhouse in summer.

scholarly journals Propagation Daily Light Integral and Root-Zone Temperature Influence Rooting of Single-internode Pennisetum ×advena Culm Cuttings

HortScience ◽  
2018 ◽  
Vol 53 (2) ◽  
pp. 176-182 ◽  
Author(s):  
W. Garrett Owen ◽  
Roberto G. Lopez
Keyword(s):  
Root Zone ◽  
Biomass Accumulation ◽  
Dry Mass ◽  
Naphthaleneacetic Acid ◽  
Root Zone Temperature ◽  
Daily Light Integral ◽  
Pennisetum Setaceum ◽  
The Impact ◽  
Light Integral ◽  
Zone Temperature

Crown division, tissue culture, and culm cuttings are methods for propagating purple fountain grass [Pennisetum ×advena Wipff and Veldkamp (formerly known as Pennisetum setaceum Forsk. Chiov. ‘Rubrum’)]. However, propagation by culm cuttings is becoming an economically attractive method for quick liner production. Our objective was to quantify the impact of propagation daily light integral (PDLI) and root-zone temperature (RZT) on root and culm development of single-internode purple fountain grass culm cuttings. Before insertion into the rooting substrate, cuttings were treated with a basal rooting hormone solution containing 1000 mg·L−1 indole-3-butyric acid (IBA) + 500 mg·L−1 1-naphthaleneacetic acid (NAA). The cuttings were placed in a glass-glazed greenhouse with an air temperature of 23 °C and benches with RZT set points of 21, 23, 25, or 27 °C. PDLIs of 4 and 10 mol·m−2·d−1 (Expt. 1) or 8 and 16 mol·m−2·d−1 (Expt. 2) were provided. After 28 d, culm and root densities (number) increased as the RZT increased from 21 to 27 °C, regardless of PDLI during Expt. 1. Compared with 4 mol·m−2·d−1, a PDLI of 10 mol·m−2·d−1 generally resulted in the greatest root biomass accumulation. For example, as PDLI increased from 4 to 10 mol·m−2·d−1, root dry mass increased by 105%, 152%, and 183% at RZTs of 21, 25, and 27 °C, respectively. In Expt. 2, as the RZT increased from 21 to 23 °C, root dry mass increased by 70% under a PDLI of 8 mol·m−2·d−1. However, root dry mass was similar among all RZTs under a PDLI of 16 mol·m−2·d−1. Our results indicate that single-internode culm cuttings of purple fountain grass can be most efficiently propagated under PDLIs of 8–10 mol·m−2·d−1 together with RZT set points of 23 to 25 °C for quick liner production.

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 Photosynthetic Daily Light Integral During the Seedling Stage Influences Subsequent Growth and Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1336-1339 ◽  
Author(s):  
Lee Ann Pramuk ◽  
Erik S. Runkle
Keyword(s):  
Growth And Development ◽  
Dry Weight ◽  
Seedling Stage ◽  
Plant Quality ◽  
Flowering Plant ◽  
Subsequent Growth ◽  
Daily Light Integral ◽  
Shoot Dry Weight ◽  
Bedding Plant ◽  
Light Integral

The photosynthetic daily light integral (DLI) dramatically increases during the spring when the majority of bedding plants are commercially produced. However, the effects of DLI on seedling growth and development have not been well characterized for most bedding plant species. Our objectives were to quantify the effects of DLI on growth and development of Celosia, Impatiens, Salvia, Tagetes, and Viola during the seedling stage and determine whether there were any residual effects of DLI on subsequent growth and development after transplant. Seedlings were grown in growth chambers for 18 to 26 days at 21 °C with a DLI ranging from 4.1 to 14.2 mol·m–2·d–1. Average seedling shoot dry weight per internode (a measure of quality) increased linearly 64%, 47%, 64%, and 68% within this DLI range in Celosia, Impatiens, Tagetes, and Viola, respectively. Seedlings were then transplanted to 10-cm containers and grown in a common environment (average daily temperature of 22 °C and DLI of 8.5 mol·m–2·d–1) to determine subsequent effects on plant growth and development. Flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola occurred 10, 12, 11, 4, and 12 days earlier, respectively, when seedlings were previously grown under the highest DLI compared with the lowest. Except for Viola, earlier flowering corresponded with the development of fewer nodes below the first flower. Flower bud number and plant shoot dry weight at first flowering (plant quality parameters) decreased as the seedling DLI increased in all species except for flower number of Tagetes. Therefore, seedlings grown under a greater DLI flowered earlier, but plant quality at first flowering was generally reduced compared with that of seedlings grown under a lower DLI.

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.

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