Researchers test effects of LEDs on leaf lettuce

Mixture of blue and red lights recommended to enhance lettuce quality, yield

2013-11-19

(Press-News.org) Contact information: Michael W. Neff
mwneff@ashs.org
703-836-4606
American Society for Horticultural Science
Researchers test effects of LEDs on leaf lettuce Mixture of blue and red lights recommended to enhance lettuce quality, yield CHEONGJU, SOUTH KOREA--In the life cycle of plants, most developmental processes are dependent on light. Significant biological processes such as germination, shade avoidance, circadian rhythms, and flower induction are all affected by light. Recent advancements in the use of LED lighting in plant and vegetable production systems has researchers looking for insights into the effects of these artificial lights on the growth and yield of crops. Scientists from the Department of Horticultural Science at Chungbuk National University published a study in HortScience that sheds some light on the advantages and challenges of LEDs in lettuce cultivation.

The increased use of LEDs in environmentally controlled closed-type plant production systems allows crop production throughout the year, regardless of external weather conditions. According to authors Ki-Ho Son and Myung-Min Oh, LEDs have some advantages over traditional lighting sources in plant cultivation. "LEDs have the advantages of high light-conversion efficiency with low radiant heat output, semipermanence, and small mass," they noted. "In addition, LEDs are available in a variety of narrow wavebands; hence, it is possible to optimize light quality to improve both crop yield and quality." They explained that blue and red LEDs are usually used for plant growth because chlorophyll a and b efficiently absorb wavelengths in the blue and red ranges.

The research design used red and green leaf lettuce subjected to six LED lighting treatments. The scientists examined growth characteristics including the fresh and dry weights of shoots and roots, shoot-to-root ratio, total leaf area, and chlorophyll content. Chlorophyll fluorescence, antioxidant capacity, phenolic concentration, and flavonoid concentration were also measured in the study. "The growth characteristic results for the two lettuce cultivars grown under various ratios of blue to red LEDs confirmed that red LED serves as a major light source that improves lettuce growth rate," the authors said.

The experiments confirmed that both blue and red LEDs have a positive effect on the accumulation of antioxidant phenolic compounds and lettuce growth, respectively. "Red light irradiation in the absence of blue light was effective at stimulating the biomass accumulation of lettuce plants; however, this lighting alone induced abnormal leaf shape and had a negative effect on polyphenolics and antioxidant levels," the scientists said. They recommended a mixture of blue and red LEDs to enhance lettuce crop quality and yield in closed-type plant production systems.

### The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/content/48/8/988.abstract

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.

ELSE PRESS RELEASES FROM THIS DATE:

Researchers develop technique to convert thermoelectric material into high performance electricity

2013-11-19

Researchers develop technique to convert thermoelectric material into high performance electricity A team of Clemson University physicists consisting of nanomaterial scientists Apparao Rao and Ramakrishna Podila and thermoelectricians Terry Tritt, Jian He and Pooja Puneet ...

The fashion scout and the cop: Scanning the streets with similar methods for different targets

2013-11-19

The fashion scout and the cop: Scanning the streets with similar methods for different targets University of Cincinnati research compares practices used by fashion industry casting directors to the New York City Police Department's controversial stop-and-frisk program. New ...

Zinc sulfate, sugar alcohol zinc sprays improve apple quality

2013-11-19

Zinc sulfate, sugar alcohol zinc sprays improve apple quality Study recommends continuing zinc application at critical stages on apple trees SHANDONG PROVINCE, CHINA--Zinc is vital for the healthy growth and reproduction of all organisms. ...

Asteroids' close encounters with Mars

2013-11-19

Asteroids' close encounters with Mars CAMBRIDGE, MA -- For nearly as long as astronomers have been able to observe asteroids, a question has gone unanswered: Why do the surfaces of most asteroids appear redder than meteorites — the remnants of asteroids ...

Researchers classify urban residential desert landscapes

2013-11-19

Researchers classify urban residential desert landscapes Information helps residents and planners create landscape budgets, manage water resources LAS CRUCES, NM--A new study contains valuable information for homeowners and horticulturalists ...

New bale unroller design deemed effective

2013-11-19

New bale unroller design deemed effective Offset round-bale unroller makes mulching more efficient in organic mulch trials LEXINGTON, KY--John Wilhoit and Timothy Coolong from the University of Kentucky have introduced a new technology that ...

First-ever survey of Do-It-Yourself Biology community challenges myths

2013-11-19

First-ever survey of Do-It-Yourself Biology community challenges myths Poll finds 'DIYers' working at community labs on benign, educational experiments WASHINGTON—As the Do-It-Yourself Biology ...

Study: Odds of rehospitalization of cognitively impaired varies by discharge destination

2013-11-19

Study: Odds of rehospitalization of cognitively impaired varies by discharge destination INDIANAPOLIS -- Cognitively impaired older adults released from the hospital are less likely to be rehospitalized within 30 days if they go to a nursing home than if they return ...

Phthalate exposure linked to preterm birth

2013-11-19

Phthalate exposure linked to preterm birth ANN ARBOR—The odds of preterm birth for women exposed to a commonly used class of chemicals known as phthalates are increased significantly, according to a new study from the University of Michigan School of Public ...

Non-specialist health workers play important role in improving mental health in developing countries

2013-11-19

Non-specialist health workers play important role in improving mental health in developing countries New research shows benefits for people with depression, anxiety, dementia, maternal depression, post traumatic stress disorder and alcohol abuse Non-specialist ...