Photosynthetic efficiency, growth and secondary metabolism of common buckwheat (Fagopyrum esculentum Moench) in different controlled-environment production systems

Light-emitting diodes (LEDs) and high-pressure sodium lamps (HPS) are among the most commonly used light sources for plant cultivation. The objective of this study was to evaluate the effect of two controlled-environment production systems differing in light sources on growth, photosynthetic activity, and secondary metabolism of common buckwheat. We hypothesized that LED light with the majority of red and blue waves would increase physiological and biochemical parameters compared to sunlight supplemented with HPS lamps. The experiment was performed in a phytotronic chamber (LEDs) and in a greenhouse (solar radiation supplemented with HPS lamps as a control). The effects were analyzed at the flowering phase with biometric measurements, leaf chlorophyll index, the kinetics of chlorophyll a fluorescence, content of soluble carbohydrates and phenolics in the leaves. Applied LED light decreased the biomass but stimulated the production of phenolics compared to control plants. In control plants, a positive correlation between flavonoid content and energy dissipation from photosystem II (DIo/CSm) was found, while in plants under LEDs total pool of phenolic content correlated with this parameter and the quantum yield of electron transport (φ Ro and ψ Ro) was lower than that of the control, probably affecting buckwheat biomass.

Different LED Light Wavelengths and Photosynthetic Photon Flux Density Effect on Colletotrichum acutatum Growth

The study aimed to evaluate the effect of different photon flux density (PFD) and light-emitting diodes (LED) wavelengths on strawberry Colletotrichum acutatum growth characteristics. The C. acutatum growth characteristics under the blue 450 nm (B), green 530 nm (G), red 660 nm (R), far-red 735 nm (FR), and white 5700 K (W) LEDs at PFD 50, 100 and 200 μmol m−2 s−1 were evaluated. The effect on C. acutatum mycelial growth evaluated by daily measuring until five days after inoculation (DAI). The presence of conidia and size (width and length) evaluated after 5 DAI. The results showed that the highest inhibition of fungus growth was achieved after 1 DAI under B and G at 50 μmol m−2 s−1 PFD. Additionally, after 1–4 DAI under B at 200 μmol m−2 s−1 PFD. The lowest conidia width was under FR at 50 μmol m−2 s−1 PFD and length under FR at 100 μmol m−2 s−1 PFD. Various LED light wavelengths influenced differences in C. acutatum colonies color. In conclusion, different photosynthetic photon flux densities and wavelengths influence C. acutatum growth characteristics. The changes in C. acutatum morphological and phenotypical characteristics could be related to its ability to spread and infect plant tissues. This study’s findings could potentially help to manage C. acutatum by LEDs in controlled environment conditions.

An Internet of Things (IoT)-Based Master-Slave Regionalized Intelligent LED-Light-Controlling System

Reducing residential and industrial electricity consumption has been a goal of governments around the world. Lighting sources account for a large portion of the whole energy/power consumption. Unfortunately, most of the existing installed lighting systems are ancient and have poor energy efficiency. Today, many manufacturers have introduced light-controlling systems into the current market. However, existing light controlling systems may not be successfully applied to buildings, streets, and industrial buildings due to high costs and difficult installation and maintenance. To combat this issue, this article presents an easy-to-install, low-cost, Master-Slave intelligent LED light-controlling system based on Internet of Things (IoT) techniques. The benefit of using the proposed system is that the brightness of the LED lights in the same zone can be changed simultaneously to save in energy consumption. Furthermore, the parameters of the LED lights can be directly set. Moreover, the related data are collected and uploaded to a cloud platform. In this article, we use 15 W T8 LED tubes (non-induction lamps) as a case study. When the proposed system is installed in a zone with few people, the energy-saving rate is as high as 90%. Furthermore, when 12 people pass by a zone within one hour, its energy-saving rate can reach 81%. Therefore, the advantages of using the proposed system include: (1) the original lamp holder can be retained; (2) no wiring is required; and (3) no server is set up. Moreover, the goal of energy saving can also be achieved. As a result, the proposed system changes the full-dark mode of the available sensor lamp to the low power low-light mode for standby. Further, it makes the sensor lamps in the same zone brighten or low-light way simultaneously, which can quickly complete large-scale energy-saving and convenient control functions of intelligent LED lighting controlling system.