Comprehensive Analysis of Photosynthetic Characteristics and Quality Improvement of Purple Cabbage under Different Combinations of Monochromatic Light

Abstract

Light is essential for plant growth. Light intensity, photoperiod, and light quality all affect plant morphology and physiology. Compared to light intensity, photoperiod, little is known about the effects of different monochromatic lights on crop species. To investigate how different lighting conditions influence crops with heterogeneous colors in leaves, we examined photosynthetic characteristics and quality (regarding edibility and nutrition) of purple cabbage under different combinations of lights. Eight different treatments were applied including monochromic red (R), monochromic blue (B), monochromic yellow (Y), monochromic green (G), and the combination of red and blue (3/1, RB), red/blue/yellow (3/1/1, RBY), red/blue/green (3/1/1,RBG), and white light as the control. Our results indicate that RBY (3/1/1) treatment promotes the PSII activity of purple cabbage, resulting in improved light energy utilization. By contrast, both G and Y lights alone have inhibitory effect on the PSII activity of purple cabbage. In addition, RBY (3/1/1) significantly boosts the anthocyanin and flavonoids content compared with other treatments. Although we detected highest soluble protein and vitamin C content under B treatment (increased by 30.0 and 14.3% compared with the control, respectively), RBY (3/1/1) appeared to be the second-best lighting condition (with soluble protein and vitamin C content increased by 8.6 and 4.1%, respectively compared with the control). Thus we prove that the addition of yellow light to the traditional combination of red/blue lighting conditions is beneficial to synthesizing photosynthetic pigments and enables superior outcome of purple cabbage growth. Our results indicate that the growth and nutritional quality of purple cabbage are greatly enhanced under RBY (3/1/1) light, and suggest that strategical management of lighting conditions holds promise in maximizing the economic efficiency of plant production and food quality of vegetables grown in controlled environments.

Influence of Light Quality and Intensity on Biomass and Biochemical Contents of Hydroponically Grown Lettuce

“…Abnormal plant morphology and reduced photosynthetic rate were observed when lettuce was exposed to red LED light alone (Goins et al, 1998;Wang et al, 2009). In a further study, blue LED alone was found to reduce the photosynthetic rate of purple cabbage (Ziwei) (Yang et al, 2016). This suggested that monochromatic red or blue light would not meet the requirements for healthy plant growth.…”

Comparisons of Different Lighting Systems for Horticultural Seedling Production Aimed at Energy Saving

“…For each lighting source of the 27 combinations, white LEDs and XTRASUN LEDs, luminous flux (Φ) (expressed in lm) and the total electric power (P) (expressed in W) were all recorded. Then, with these measurements we determined the luminous efficacy (η) (expressed in lm W −1 ) using Equation (1). The minimum illumination level (Ev) was calculated dividing the value of Φ by the surface (S) (1.2 m 2 ) (expressed in lx) and the limit value of energy efficiency (VEEI) (expressed in W m −2 ) was then calculated using Equation (2) following the methodology established by Hidalgo et al [20].…”

“…Light is one of the most important environmental regulators for the growth of crop species since it provides essential energy input and triggers various signaling pathways for the dynamic growth regulation of crops [1]. In this sense, plant species have evolved photoreceptors to sense the light environment and adjust to changing environmental conditions through the modulation of cellular processes [2].…”

“…In addition, there are different studies worldwide regarding the use of LEDs during healing and acclimatization in seedlings in different crops such as tomato [18] and pepper [19]. Nevertheless, there are few references about this topic under nurseries as productions systems in southern Spain; therefore, the aims of this work are: (1) to evaluate technical and spectral irradiance of the different types of FL (TLD, TL5 and CF) commonly used in nurseries, LEDs lamps (blue (B), red (R) and red + blue (violet) (V)) with a high saving energy and their different combinations with FL due to the spectral enrichment, and novel types of LEDs such as white LEDs (W) and XTRASUN LEDs; and (2) to theoretically estimate the potential growth of tomato and cucumber seedlings under the lamps assessed.…”

Fittonia verschaffeltii Response to Artificial Light Treatments: BIOMASS, Nutrient Concentrations and Physiological Changes

“…Illumination is a powerful environmental stimulus with impacts on a wide range of plant metabolic processes [1]. The ability of plants to sense and respond to light depends on their photosynthetic pigments and photoreceptors that absorb different wavelengths of the light [2].…”