Long-term acclimation of barley photosynthetic apparatus to narrow-band red and blue light

et al. 2020

BMC Plant Biol

Background: The optimized illumination of plants using light-emitting diodes (LEDs) is beneficial to their photosynthetic performance, and in recent years, LEDs have been widely used in horticultural facilities. However, there are significant differences in the responses of different crops to different wavelengths of light. Thus, the influence of artificial light on photosynthesis requires further investigation to provide theoretical guidelines for the light environments used in industrial crop production. In this study, we tested the effects of different LEDs (white, W; blue, B; green, G; yellow, Y; and red, R) with the same photon flux density (300 μmol/m 2 •s) on the growth, development, photosynthesis, chlorophyll fluorescence characteristics, leaf structure, and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) plants. Results: Plants in the W and B treatments had significantly higher height, leaf area, and fresh weight than those in the other treatments. The photosynthetic pigment content and net photosynthetic rate (P n) in the W treatment were significantly higher than those in the monochromatic light treatments, the transpiration rate (E) and stomatal conductance (G s) were the highest in the B treatment, and the intercellular CO 2 concentration (C i) was the highest in the Y treatment. The non-photochemical quenching coefficient (NPQ) was the highest in the Y treatment, but the other chlorophyll fluorescence characteristics differed among treatments in the following order: W > B > R > G > Y. This includes the maximum photochemical efficiency of photosystem II (PSII) under dark adaptation (Fv/Fm), maximum photochemical efficiency of PSII under light adaptation (Fv′/Fm′), photochemical quenching coefficient (qP), actual photochemical efficiency (ΦPSII), and apparent electron transport rate (ETR). Finally, the leaf structure and chloroplast ultrastructure showed the most complete development in the B treatment. Conclusions: White and blue light significantly improved the photosynthetic efficiency of Welsh onions, whereas yellow light reduced the photosynthetic efficiency.

Section: Discussionsupporting

confidence: 91%

“…The grana also had a large diameter, irregular shape, and many prominent thylakoids. In some areas, the thylakoids were disordered [66]. This was not the case for the chloroplasts of the R-treated Welsh onions in this study; the chloroplasts were relatively intact, which may reflect differences based on species.…”

Section: Discussioncontrasting

confidence: 57%

Photosynthetic characteristics and chloroplast ultrastructure of welsh onion (Allium fistulosum L.) grown under different LED wavelengths

et al. 2020

BMC Plant Biol

“…This may be related to the expression of a number of chloroplast-encoded genes requires high irradiance B light [66]. Our results show that the chloroplast membrane structure under B light is similar to that under W light treatment, consistent with the results of studies on barley leaves [67]. However, compared with the chloroplast of barley leaves under W light, the number of thylakoid membranes and the length of the extended accumulation zone in the chloroplasts under R light increased significantly.…”

Section: Discussionsupporting

confidence: 90%

Responses of the photosynthetic characteristics and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) to different LED light qualities

et al. 2019

Preprint

Background: The optimized illumination of plants using light-emitting diodes (LEDs) is beneficial to theirphotosynthetic performance. Because of this, in recent years LEDs have been widely used in horticultural facilities. However, there are significant differences in the responses of different crops to light quality. The influence of light quality on photosynthesis needs to be further explored to provide theoretical guidance for the adjustment of the light environment in industrial crop production. This study tested the effects of different qualities of LED lighting (white, W; blue, B; green, G; yellow, Y; and red, R) with the sama photon flux density (300 μmol/m2·s) on the growth and development, photosynthesis, chlorophyll fluorescence characteristics, leaf structure, and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) plants. Results: The results showed that the plant height, leaf area, and fresh weight of plants in the W and B treatments were significantly higher than those in the other treatments. The photosynthetic pigment content and net photosynthetic ratein the W treatment were significantly higher than those in the monochromatic light treatments, while the transpiration rate (E) and stomatal conductance (Gs) were the highest in the B treatment, and the intercellular CO2 concentration (Ci) was the highest in the Y treatment. Among the chlorophyll fluorescence characteristics tested, the non-photochemical quenching coefficient (NPQ) was the highest in the Y treatment, while the maximum photochemical efficiency of photosystem II (PSII) under dark adaptation (Fv/Fm), maximum photochemical efficiency of PSII under light adaptation (Fv'/Fm'), photochemical quenching coefficient (qP), actual photochemical efficiency (ΦPSII), and apparent electron transport rate (ETR) all differed among treatments in the following order: W > B > R > G > Y. Both leaf structure and chloroplast ultrastructure showed the most complete development in the B treatment. Conclusions: In summary, in addition to W light, B light significantly improved the photosynthetic efficiency of Welsh onion, whereas Y light significantly reduced the photosynthetic efficiency of this plant.

“…Li [61] Grana has a large diameter and irregular shape, and many prominent thylakoids. In some areas, the thylakoids are disordered [63]. The structure of chloroplasts in leaves of R-treated Welsh onion is not the same.…”

Section: Response Of Rubpcase Activity In Welsh Onion To Different Lementioning

confidence: 96%

Responses of the photosynthetic characteristics and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) to different LED light qualities

et al. 2019

Preprint

Background: The optimized illumination of plants using light-emitting diodes (LEDs) is beneficial to their photosynthetic performance. Because of this, in recent years LEDs have been widely used in horticultural facilities. However, there are significant differences in the responses of different crops to light quality. The influence of light quality on photosynthesis needs to be further explored to provide theoretical guidance for the adjustment of the light environment in industrial crop production. This study tested the effects of different qualities of LED lighting (white, W; blue, B; green, G; yellow, Y; and red, R) with the same photon flux density (300 μmol/m2·s) on the growth and development, photosynthesis, chlorophyll fluorescence characteristics, leaf structure, and chloroplast ultrastructure of Welsh onion (Allium fistulosum L.) plants. Results: The results showed that the plant height, leaf area, and fresh weight of plants in the W and B treatments were significantly higher than those in the other treatments. The photosynthetic pigment content and net photosynthetic rate (Pn) in the W treatment were significantly higher than those in the monochromatic light treatments, while the transpiration rate (E) and stomatal conductance (Gs) were the highest in the B treatment, and the intercellular CO2 concentration (Ci) was the highest in the Y treatment. Among the chlorophyll fluorescence characteristics tested, the non-photochemical quenching coefficient (NPQ) was the highest in the Y treatment, while the maximum photochemical efficiency of photosystem II (PSII) under dark adaptation (Fv/Fm), maximum photochemical efficiency of PSII under light adaptation (Fv'/Fm'), photochemical quenching coefficient (qP), actual photochemical efficiency (ΦPSII), and apparent electron transport rate (ETR) all differed among treatments in the following order: W > B > R > G > Y. Both leaf structure and chloroplast ultrastructure showed the most complete development in the B treatment. Conclusions: In summary, in addition to W light, B light significantly improved the photosynthetic efficiency of Welsh onion, whereas Y light significantly reduced the photosynthetic efficiency of this plant.