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Lie Li, Yu-xin Tong, Jun-ling Lu, Yang-mei Li, and Qi-chang Yang

necessary to investigate an optimal combination of specific light wavelengths for plant growth rather than using white light with a broad spectrum or simple mixed R and B ( Gupta and Jatothu, 2013 ). Moreover, additional research is needed to determine the

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Dominic P. Petrella, James D. Metzger, Joshua J. Blakeslee, Edward J. Nangle, and David S. Gardner

). Therefore, anthocyanin content may increase through a combination of photosynthetic and photoreceptor-mediated regulation when blue, red, and/or combinations of blue and red light are applied. Given the previously established regulation of anthocyanin

Open access

Andrea Stuemky and Mark E. Uchanski

sustainability, as well as opportunities for off-season production ( Massa et al., 2008 ; Morrow, 2008 ). Individual diodes that make up LED light fixtures range in their color spectra (i.e., wavelengths), which are typically comprised of a combination of blue

Open access

Humberto Aguirre-Becerra, Juan Fernando García-Trejo, Cristina Vázquez-Hernández, Aurora Mariana Alvarado, Ana Angélica Feregrino-Pérez, Luis Miguel Contreras-Medina, and Ramón G. Guevara-Gonzalez

Light is one of the most important factors for plant growth and development. The light source can be natural, artificial, or a combination of both, and their quantity and quality lead to different plant development results ( Xu, 2019 ). Positive

Free access

Venkat K. Reddy and Nihal C. Rajapakse

The influence of removal of specific wavelengths [red (R), blue (B), and farred (FR)] from sunlight on the height of chrysanthemum plants was investigated by overlaying Roscolux™ colored acetate films on 4% CuSO4 or water (control) spectral filters. CuSO4 filters removed FR wavelengths and significantly reduced plant height and internode length compared to control plants that received B, R, and FR wavelengths of light. Plants grown under Roscolux blue filters did not receive R light and were significantly taller compared to plants from any other treatments. Plants grown under Roscolux red filters did not receive B light and were significantly shorter compared to plants from other treatments. Leaf area, leaf dry weight, and stem dry weight were highest in plants grown under Roscolux red and control filter combination. The amount of leaf chlorophyll and the ratio of Chl A: Chl B was highest in plants grown under Roscolux blue filters. In general, plants that received FR light (control + film) were taller than the plants that did not receive FR light in the corresponding (CuSO4 + film) filter combination. The influence of removal of specific wavelengths on plant height control and developmental physiology will be discussed.

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Christopher S. Brown, Andrew C. Schuerger, and John C. Sager

, and Peter Hadeland for the LED arrays used in this study. We also thank Raymond M. Wheeler for his help and advice, Baishnab C. Tripathy for his critical reading of the manuscript and Neil C. Yorio for assistance with the spectral scans. Mention of a

Open access

Haijie Dou, Genhua Niu, Mengmeng Gu, and Joseph Masabni

). With the advancement of light-emitting diode (LED) technology and its customizable nature, the effects of different light wavelengths on plant growth and secondary metabolites accumulation can be characterized ( Darko et al., 2014 ; Mitchell et al

Free access

Paolo Sambo, Giorgio Gianquinto, and Valente Forte

Several experiments on multispectral radiometer showed its suitability in driving nitrogen fertigation in tomato crop. Nir-Green light ratio describes crop nitrogen status well, highlighting element deficiency or excess, which is a great help to farmers in choosing timing and intensity of fertilizer application. The scientific literature reports several studies about nitrogen management only, but not phosphorus and potassium. Because of the advantage obtained with N, it would be desirable to also adapt it to phosphorus and potassium management. For this purpose, a preliminary trial was carried out on the omato cultivar Brigade grown in pots in a greenhouse. Four nutrient solution were supplied. Three were lacking in N, P, or K—the last had all elements needed for a balanced growth. Radiometer readings were taken once a week during the crop cycle, around noon. First results were encouraging. After some data elaboration, it appeared evident that, in some cases, it was possible to set the fertigation treatments apart by only having a look at the single wavelengths measured by the instrument. Through the Nir/green index, used in N management, phosphorus deficiency was identified as well. Potassium trend line was completely different from those of nitrogen and phosphorus, and very similar to that of the control. The utilization of the radiometer in handling potassium fertigation in tomato appeared somewhat difficult. Its application might be desirable, instead, for phosphorus fertigation in addition to nitrogen. The 560 and 710 nm wavelengths might be the especially more useful for this purpose, although a simple index or a combination of some simple indices able to identify phosphorous deficiency/excess and to screen them from those induced by nitrogen are needed.

Free access

Kui Lin, Zhi Huang, and Yong Xu

). This can be effectively demonstrated by using various wavelengths to regulate plant growth patterns. For example, red light plays a significant role in photosynthetic reactions and the transport of assimilates ( Baroli et al., 2008 ), induces callus

Free access

Shih-Wei Kong, Hsin-Ying Chung, Ming-Yi Chang, and Wei Fang

low absorptivity coefficient in the absorption spectra of purified chlorophylls ( Sun et al., 1998 ). Light-emitting diodes (LEDs) allow production of light that emit only the wavelengths of light corresponding to the absorption peaks of plant