Optimization of Light Quality for Plant Factory Production of Brassica campestris (Pakchoi)
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
See the attached comments.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
This study investigates the effects of different light qualities (white, white:red, white:blue, white:red:blue, and white:green) on the growth, chloroplast structure, and nutritional quality of pakchoi (Brassica campestris L.) in a controlled plant factory environment. The research is highly relevant, addressing critical questions regarding the optimization of artificial light spectra for crop growth and nutritional enhancement. The study addresses a key challenge in controlled-environment agriculture, focusing on optimizing light spectra for crop production. The results are well-presented, showing clear differences in growth, enzyme activity, and nutritional quality under different light treatments. The findings provide valuable insights for practical applications in plant factory systems, particularly regarding supplemental lighting strategies. However, some results would benefit from more detailed statistical analysis, including effect sizes and interaction terms. While the results are well-documented, the discussion section could further contextualize findings within the broader body of literature on LED lighting in crop cultivation. Moreover, the study briefly mentions energy consumption as a challenge but does not provide data or analysis on the energy efficiency of different light treatments. I suggest it can be accepted after the following revisions are made.
1. Consider adding a brief mention of the practical implications in the abstract.
2. Include more recent studies to contextualize your research and highlight the novelty of your experimental design in the introduction.
3. Include a summary table of key parameters for light treatments for quick reference in the materials and methods.
4. Clarify some enzyme activity results (e.g., SPS and SS) with supporting explanations for observed trends.
5. Improve the readability of figures, especially those comparing enzyme activities across treatments.
6. Deepen the comparison with previous studies, especially regarding red and blue light effects on carbon and nitrogen metabolism.
7. Address the broader implications for commercial plant factory operations.
8. Discuss the energy implications of different light treatments.
9. I suggest concrete future research directions in the conclusion, such as exploring more dynamic light schedules or testing other vegetable crops.
Author Response
Dear reviewer:
Thank you for your helpful comments concerning my manuscript. These comments are very valuable and meaningful for improving our manuscript academic quality, and they are important guiding significance to our future research. We have carried out the corrections following all the comments.
Responses to the comments.
Point 1: Consider adding a brief mention of the practical implications in the abstract.
Response 1: According to your suggestion, we have added a brief mention of the practical implications in the abstract.
“Therefore, supplemental red-blue mixed light can effectively improve the growth and nu-tritional properties of pakchoi grown under white light. This supplementary lighting strategy provides a new way to enhance the nutritional value of leafy vegetables in plant factories.” in Lines 26-29.
Point 2: Include more recent studies to contextualize your research and highlight the novelty of your experimental design in the introduction.
Response 2: Thanks for your reminding, we have added more recent studies to contextualize our research. Such as:
“Appropriate blue light treatment is also beneficial for increasing the content of important nutrients such as phenolic acids, glucosinolates, and flavonoids [10]. Additionally, research has demonstrated that supplemental green light can significantly contribute to photosynthetic carbon assimilation and enhance both the yield and nutritional quality of plants [3,11,12]. However, plants growing under monochromatic light often experience physiological problems such as decreased photosynthetic capacity and growth inhibition [13]. For example, due to the short-wavelength and high-energy radiation properties of blue light, strong exposure to monochromatic blue light can cause plant leaves to shrink and grow slowly [14]. To avoid this phenomenon, our research supplements red, blue, and green light on the basis of white light.” in Lines 60-69.
Cited the reference:
[10] Zhang, R.; He, Q.; Pan, Q.; Feng, Y.; Shi, Y.; Li, G.; Zhang, Y.; Liu, Y.; Khan, A. Blue-green light treatment enhances the quality and nutritional value in postharvest Chinese cabbage (Brassica rapa L. ssp. pekinensis). Food Chemistry. 2024, 24, 102004.
[12] Zhang, R.; Liu, Y.; Pan, Q.; Khan, A.; Bai, X.; Ali, M.; Yang, W.; Zhang, L.; Li, B. The effects of short term blue light treatment on promoting nutrition value in Chinese cabbage. Food Chemistry. 2023, 412, 135542.
[13] Izzo, L.G.; Arena, C.; De Micco, V.; Capozzi, F.; Aronne, G. Light quality shapes morpho-functional traits and pigment content of green and red leaf cultivars of Atriplex hortensis. Scientia Horticulturae. 2019, 246, 942-950.
[14] Izzo, L.G.; Hay Mele, B.; Vitale, L.; Vitale, E.; Arena, C. The role of monochromatic red and blue light in tomato early photomorphogenesis and photosynthetic traits. Environmental and Experimental Botany. 2020, 179, 104195.
And we have highlighted the novelty of our experimental design in the introduction.
“In accordance with previous research, optimizing light quality conditions is crucial for improving both yield and quality. Red and blue light have been widely studied in plant factory cultivation experiments, and green light has also been partially studied. However, research on supplementing red, blue, and green light on the basis of white light is still rare.” in Lines 83-87.
Point 3: Include a summary table of key parameters for light treatments for quick reference in the materials and methods.”
Response 3: Thanks for your precious suggestion, we have added a figure and table of key parameters for light treatments for quick reference in the materials and methods. Such as:
Figure 1. Relative spectral value of four treatments.
Table 1. Effect of supplementary light quality on the growth of pakchoi.
|
Treatments |
PPFD of W (µmol·m−2·s−1) |
PPFD of B (µmol·m−2·s−1) |
PPFD of R (µmol·m−2·s−1) |
PPFD of G (µmol·m−2·s−1) |
Total PPFD (µmol·m−2·s−1) |
|
CK |
250 |
\ |
\ |
\ |
250 |
|
WB |
200 |
50 |
\ |
\ |
250 |
|
WRB |
150 |
50 |
50 |
\ |
250 |
|
WR |
200 |
\ |
50 |
\ |
250 |
|
WG |
200 |
\ |
\ |
50 |
250 |
W: white light; B: additional blue light supplement; R: additional red light supplement; G: additional green light supplement.
Point 4: Clarify some enzyme activity results (e.g., SPS and SS) with supporting explanations for observed trends.
Response 4: Thanks for your precious suggestion, we have clarify some enzyme activity results (e.g., SPS and SS) and provided supporting explanations for observed trends.
“At the same time, supplementing with blue light (WB) only increased the content of solu-ble sugars; however, after supplementing with red blue mixed light, the carbohydrate content was significantly higher than other treatment groups, and the activity of sucrose metabolism related enzymes such as SPS was significantly increased (Figure 2). This in-dicates that the combination of red and blue light is not a simple additive effect, but can regulate the production and accumulation of carbohydrates by regulating the activity of carbon metabolism related enzymes. According to Ren et al.'s research, the combined treatment of red and blue light can increase the expression of various carbon metabolism related genes, including the SPS related gene SPS1 [18]. It is interesting that the trend of SS activity changes under WRB treatment is completely opposite to SPS, which may be due to the fact that most SS was used to decompose sucrose rather than synthesize sucrose.” in Lines 442-452.
Point 5: Improve the readability of figures, especially those comparing enzyme activities across treatments.
Response 5: Thanks for your reminding, we have improved the readability of all figures in our manuscript.
For example:
Figure 3. Effect of supplementary light quality on the activities of a variety of enzymes of pakchoi leaves. (A) sucrose phosphate synthetase (SPS); (B) sucrose synthase (SS); (C)nitrate reductase (NR); (D) glutamine synthetase (GS); (E) glutamate synthetase (GOGAT); and (F) glutamate dehydrogenase (GDH). Different letters indicate significant differences using the Duncan’s Multiple Range Test (P < 0.05; n = 5).
Point 6: Deepen the comparison with previous studies, especially regarding red and blue light effects on carbon and nitrogen metabolism.
Response 6: Thanks for your reminding, we have deepened the comparison with previous studies on the effects of red and blue light on carbon and nitrogen metabolism. Such as:
“At the same time, supplementing with blue light (WB) only increased the content of solu-ble sugars; however, after supplementing with red blue mixed light, the carbohydrate content was significantly higher than other treatment groups, and the activity of sucrose metabolism related enzymes such as SPS was significantly increased (Figure 2). This in-dicates that the combination of red and blue light is not a simple additive effect, but can regulate the production and accumulation of carbohydrates by regulating the activity of carbon metabolism related enzymes. According to Ren et al.'s research, the combined treatment of red and blue light can increase the expression of various carbon metabolism related genes, including the SPS related gene SPS1 [18]. It is interesting that the trend of SS activity changes under WRB treatment is completely opposite to SPS, which may be due to the fact that most SS was used to decompose sucrose rather than synthesize sucrose.” in Lines 442-452.
“These effects may be attributed to blue and red light promoting the synthesis of soluble proteins, thereby increasing the supply of enzymes that reduce nitrate and NADPH in the leaves, and the accumulation of high levels of amino acids also negatively regulates ni-trate absorption [2,39]. The combination of red and blue light further enhances the activity of nitrogen metabolism enzymes, resulting in more synthesis of amino acids and soluble proteins, leading to lower nitrate content. However, the molecular mechanism of how the combination of red and blue light enhances the activity of nitrogen metabolism enzymes still needs further research. At the same time, the supplementation of green light can effectively reduce nitrate content, which is consistent with the research results of Bian et al. [22]. However, in this experiment, green light had no significant effect on NR activity, which is speculated to be related to the synthesis of soluble proteins.” in Lines 469-480.
Point 7: Address the broader implications for commercial plant factory operations.
Response 7: Thanks for your precious suggestion, we have addressed the broader implications for commercial plant factory operations.
“Our research results further validate the functional effects of red, blue, and green light on plants, providing relevant technical guidance for the artificial light configuration of leafy vegetables in plant factories, and improving the commercial economic benefits of pakchoi in plant factories.” in Lines 551-554.
Point 8: Discuss the energy implications of different light treatments.
Response 8: We do thank your helpful suggestion. The light intensity of all treatment groups in this experiment is consistent, and we do not consider the impact on energy. In future experiments, we will consider the energy implications of different light treatments.
Point 9: I suggest concrete future research directions in the conclusion, such as exploring more dynamic light schedules or testing other vegetable crops.
Response 9: According to your precious suggestion, we have concreted future research directions in the conclusion.
“However, the effectiveness of this supplementary light scheme in improving the growth and quality of other non leafy vegetables remains to be verified, and the molecular mechanism of red blue mixed light regulating carbon and nitrogen metabolism also needs further detailed research.” in Lines 555-559.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
Kindly find attached comments.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
