Effects of light spectrum on morpho-physiological traits of grafted tomato seedlings

• Published in: PloS one Vol. 16; no. 5; p. e0250210
• Main Authors: Yousef, Ahmed F, Ali, Muhammad M, Rizwan, Hafiz M, Ahmed, Mohamed A A, Ali, Waleed M, Kalaji, Hazem M, Elsheery, Nabil, Wróbel, Jacek, Xu, Yong, Chen, Faxing
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07-05-2021; Public Library of Science (PLoS)
• Subjects: Agricultural engineering; Agricultural production; Agriculture; Analysis; Bioengineering; Biology and Life Sciences; Botany; Carotenoids; Carotenoids - metabolism; Chlorophyll - metabolism; Chloroplasts; Computer programs; Drafting software; Durability; Editing; Electron transport; Electronic engineering; Electronic mail; Engineering and Technology; Environmental conditions; Forestry; Funding; Gene expression; Gene Expression Regulation, Plant; Growth; Horticulture; Learning algorithms; Light; Light emitting diodes; Light intensity; Light sources; Luminous intensity; Machine learning; Medicinal plants; Methodology; Methods; Photochemicals; Photochemistry; Photosynthesis; Photosystem II; Physical Sciences; Physiological effects; Physiology; Plant growth; Plant Leaves - radiation effects; Plant physiology; Plant production; Plant resistance; Proteins; RNA polymerase; Seedlings; Seedlings - growth & development; Seedlings - radiation effects; Software; Solanum lycopersicum - growth & development; Solanum lycopersicum - physiology; Solanum lycopersicum - radiation effects; Technology; Tomatoes; Transport rate; China; Poland; Egypt
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0250210

It is already known that there are many factors responsible for the successful grafting process in plants, including light intensity. However, the influence of the spectrum of light-emitting diodes (LEDs) on this process has almost never been tested. During the pre-grafting process tomato seedlings grew for 30 days under 100 μmol m-2 s-1 of mixed LEDs (red 70%+ blue 30%). During the post-grafting period, seedlings grew for 20 days under the same light intensity but the lightening source was either red LED, mixed LEDs (red 70% + blue 30%), blue LED or white fluorescent lamps. This was done to determine which light source(s) could better improve seedling quality and increase grafting success. Our results showed that application of red and blue light mixture (R7:B3) caused significant increase in total leaf area, dry weight (total, shoot and root), total chlorophyll/carotenoid ratio, soluble protein and sugar content. Moreover, this light treatment maintained better photosynthetic performance i.e. more effective quantum yield of PSII photochemistry Y(II), better photochemical quenching (qP), and higher electron transport rate (ETR). This can be partially explained by the observed upregulation of gene expression levels of PsaA and PsbA and the parallel protein expression levels. This in turn could lead to better functioning of the photosynthetic apparatus of tomato seedlings and then to faster production of photoassimilate ready to be translocated to various tissues and organs, including those most in need, i.e., involved in the formation of the graft union.