When consumers visit garden centers in spring they will most likely buy flowering ornamental plants that are ready for their home gardens. Studies have shown that consumers favor plants that are already in flower rather than those that are "vegetative"—a preference that can present multiple challenges for commercial growers.
To satisfy consumers' wishes, producers of ready-to-flower ornamentals like bedding plants and perennials start growing crops far in advance of the spring buying season, often during the dark and short days of winter. When the days are short, commercial growers turn to "light manipulation" techniques that either promote or prevent flowering in preparation for delivery to markets. New research from a team at Michigan State University offers commercial plant producers a cost-effective method for producing market-ready plants that appeal to both consumers and retailers.
"Long-day" plants are varieties in which flowering is promoted under short periods of darkness, whereas "short-day" plants flower when the dark period exceeds a critical duration. To satisfy spring markets, some commercial ornamental growers create artificial long-day (LD) environments to produce flowering plants for delivery to retailers. Growers employ several methods to promote flowering in LD plants under natural short photoperiods. Methods include extending day length with artificial lighting, shortening the period of darkness by providing night-interruption (NI) lighting, or using cyclic or intermittent lighting during which incandescent lamps are turned on and off at specific intervals for a certain duration.
Matthew G. Blanchard and Erik S. Runkle from the Department of Horticulture at Michigan State designed an experiment to evaluate a technology for long-day lighting for commercial production of ornamentals. The experiment used four popular flowering ornamentals (campanula, coreopsis, petunia, and rudbeckia) to compare the efficacy of a rotating high-pressure sodium lamp (HPS) in promoting flowering with night-interruption lighting using incandescent lamps.
Seedlings were grown under natural short-day photoperiods (12 hours or less) and night-interruption treatments were delivered from a rotating HPS lamp mounted at one gable end of the greenhouse or from incandescent lamps that were illuminated continuously for four hours or cyclically for 6 minutes every 30 minutes for 4 hours. Within 16 weeks, 80% or more of the plants of each species that received night-interruption lighting had a visible flower bud or inflorescence; all species but petunia remained vegetative under the short-day treatment. Flowering of all species grown at 13 meters from the rotating HPS lamp was delayed by 14 to 31 days compared with those under continuous incandescent illumination.
The researchers estimated that the weekly cost to operate night-interruption lighting was an impressive 80% to 83% less than the cost of continuous incandescent lighting. According to Blanchard and Runkle, "a rotating HPS lamp operated continuously during a 4-hour night-interruption was effective at promoting flowering in these long-day species and consumed less energy compared with incandescent lamps operated continuously." The researchers concluded that use of rotating high-pressure sodium lamps could be effective in commercial production as long as the light intensity is above the recommended value.
The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/cgi/content/abstract/45/2/236
Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.org
Michael W. Neff | EurekAlert!
Energy crop production on conservation lands may not boost greenhouse gases
13.03.2017 | Penn State
How nature creates forest diversity
07.03.2017 | International Institute for Applied Systems Analysis (IIASA)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy