Editorial: Enhancement of Photosynthesis through Light Utilization in Plants and Crops

Jose R Peralta-Videa^1*Sina Fallah²Meijian Yang³

• ¹The University of Texas at El Paso, El Paso, United States
• ²Shahrekord University, Shahrekord, Iran
• ³Columbia Climate School, Columbia University, New York City, New York, United States

The University of Texas at El Paso, Department of Chemistry and Biochemistry, Chemistry and Computer Science Building, 500 West University Ave., El Paso, TX 79968, USAThe essential role of light in photosynthesis was discovered almost two and a half centuries ago by the Dutch physician Jan Ingen-Housz, who demonstrated that plants exposed to light restored oxygen (Stirbet et al., 2020). In 1872, Jean Senebier et al. demonstrated that CO 2 was needed to restore O 2 in light-exposed plants (Shevela et al., 2019). Since then, thousands of articles have been written describing the role of light in photosynthesis.Crop production is reduced due to changes in photosynthesis, which is affected by environmental conditions, such as CO 2 excess/lack or water shortage. He and Matthews (2023) mentioned that the elevated CO 2 concentration impacted photosynthesis and reduced yield in soybeans. Water and fertilizer supply also affect photosynthesis and yield. Chastain et al. (2014) evaluated the effects of water deficit on net photosynthesis and lint production in a field experiment with three cotton (Gossypium hirsutum) cultivars for two years. The cultivars were ground in a dryland with rainfall only or well-watered during the growing season. They found that under water deficit, there was a decrease in stomatal conductance and an increase in photorespiration, ending in a reduction of net photosynthesis and lint yield (in one of the seasons only).Cultivation under a controlled environment may help combat climate uncertainties and maintain the food supply in regions with limited arable land. However, this requires a specific structure to improve and sustain photosynthesis. This Special Issue includes 10 articles discussing key factors impacting photosynthesis and crop production under controlled conditions. Six of these articles discuss different effects of the light spectrum, mainly red and far-red light effects. One presents the impact of cell size on photosynthesis. Another one explores the interaction of CO 2 with light, and the others discuss different aspects of photosynthesis and plant growth, such as light intensity. The light intensity affects photosynthesis in different manners depending on the type of plant. There has been an inconsistency regarding the number of days plants can tolerate days with low daily light integral (DLI) after exposure to a day with high DLI from natural light. Previous reports referred to a single day, which practically eliminates the use of supplemental light. Mayorga-Gomez et al. (https://doi.org/10.3389/fpls.2024.1467443) experimented with lettuce (Lactuca sativa) exposed to a day with a high DLI (22.5 mol/m 2 *day) followed by a varying number of days with low DLI. They report that lettuce plants exposed for one day to high DLI can endure multiple days on low DLI, which can end in reduced energy consumption. CO 2 concentration and light intensity affect photosynthesis, stomatal conductance, and leaf transpiration. Lv et al. (https://doi.org/10.3389/fpls.2024.1397948) report that increased photosynthetically active radiation in rice rapidly increases stomatal conductance, transpiration, and net photosynthesis. Conversely, increasing the CO 2 concentration gradually decreases stomatal conductance and transpiration, but photosynthesis linearly and slowly increases as leaf development increases until stabilization. However, the CO 2 absorption by leaves depends on several factors, including light and CO 2 volume variations. Ogolla et al. (https://doi.org/10.3389/fpls.2024.1422814) report that cell size is another factor influencing the photosynthetic rate. They studied Mesoamerican and Andean common beans and found that the first has smaller epidermal cells with higher stomatal density, which allows higher water and CO 2 conductance. This helps the plants to increase chlorophyll and protein content.Another light parameter to consider is the spectrum. Changes in red and far-red spectra have been shown to affect plant development differently. Bi et al. (https://doi.org/10.3389/fpls.2024.1430241) evaluated the effects of changes in the red and far-red light ratio on biochemical parameters and the nutritional quality of lettuce. They compared the effects of 450 nm blue light + 650 nm red light (control) with 650 nm red light + 730 nm far-red light in a ratio of 3:2 (F3). They found that plants exposed to F3 had significantly more net photosynthesis rate, stomatal conductance, leaf area, aboveground fresh weight, vitamin C, and total soluble sugar. The duration of far-red light, which affects phytochrome, impacts plant development. Igarashi et al. (https://doi.org/10.3389/fpls.2025.1496790) illuminated 120-300 sec leaves of arugula with LED light of 735 nm (far-red) and 635 nm (red) plus a laser light of 852 nm to produce biospeckles for rapid evaluation of far-red influence. They found that short exposure to farred light increased internal activity compared with prolonged exposure. They also found that the response of one-month-old leaves was better than that of three-month-old leaves. Chen et al. (https://doi.org/10.3389/fpls.2024.1465004) reported that reducing red light in full-spectrum LEDs causes a significant impact on the growth of the propagation remains of strawberries. White LEDs increased by 83% of the total dry mass of runner plants compared to red and blue LEDs. On the other hand, Ke et al.(https://doi.org/10.3389/fpls.2024.1393918) cultivated Micro-Tom and Rejina tomatoes exposed to monochromatic red light, red/blue light ratio = 3, and white light at 300 µmol/m 2 *s. The monochromatic red light photosynthetic rate resulted in the lowest radiation use efficiency. The highest blue light proportion (up to 25%) resulted in the highest photosynthetic rate and radiation use efficiency. The blue light produced the best effects on fruits. Similar results were reported by Almeida Lima et al. (https://doi.org/10.3389/fpls.2023.1261174) on microtomato plants exposed for 12 h to blue light at 300 µmol/m 2 *s and 3.7 W/m 2 UV-B for 1 h daily. These plants had the highest photosynthetic rates and fruits with the highest rutin content compared to red and white lights. Li et al. (https://doi.org/10.3389/fpls.2024.1397948) stated that crop production may increase under suboptimal conditions by improving far-red utilization. This is because only a tiny portion of far-red light is used in photosynthesis. On the other hand, Caddell et al. (https://doi.org/10.3389/fpls.2023.1050483) mentioned that antenna assembly component genes CpSRP43, CpSRP54a, and their paralog, CpSRP54b, have a high photosynthetic contribution to chlorophyll content. This impacts plants that grow in mixed communities.Articles included in this Special Issue contribute to further understanding of the many facets played by light to enhance photosynthesis and improve plant growth under controlled conditions. There are still several aspects to be studied, such as the varietal response and the effects of light on plants exposed to nanoagrochemicals.