`The effects of light on plant growth and development

       Light provides plants with the energy required for photosynthesis, allowing them to produce organic matter and convert energy during growth and development. Light provides plants with the necessary energy and is the basis for cell division and differentiation, chlorophyll synthesis, tissue growth and stomatal movement. Light intensity, photoperiod and light quality play an important role in these processes. Sugar metabolism in plants involves many regulatory mechanisms. Light, as one of the regulatory factors, affects the composition of the cell wall, starch granules, sucrose synthesis and the formation of vascular bundles. Similarly, in the context of light-regulated sugar metabolism, sugar types and genes are also affected. We examined the existing databases and found few relevant reviews. Therefore, this article summarizes the effects of light on plant growth and development as well as sugar metabolism and discusses the mechanisms of light effects on plants in more detail, providing new insights into the regulatory mechanisms of plant growth under different light conditions.

       Light provides energy for plant photosynthesis and acts as an environmental signal regulating multiple aspects of plant physiology. Plants can sense changes in external light conditions through various photoreceptors such as phytochromes and phototropins and establish appropriate signaling pathways to regulate their growth and development. Under low light conditions, total plant dry matter content decreases, as does photosynthesis rate, transpiration rate, stomatal conductance, and stem diameter . In addition, light intensity is a critical variable regulating processes such as plant germination, leaf proliferation and expansion, stomatal development, photosynthesis, and cell division. Light quality transmitted through photoreceptors regulates the entire life cycle of plants, with different light quality having different effects on plant morphology, photosynthesis, growth and organ development . Plants can regulate their growth and development in response to photoperiod, which promotes processes such as seed germination, flowering and fruit ripening. It is also involved in plant responses to adverse factors, adapting to various seasonal changes (Bao et al., 2024; Chen et al., 2024; Shibaeva et al., 2024).
       Sugar, a fundamental substance for plant growth and development, undergoes a complex transport and accumulation process that is influenced and regulated by multiple factors. Sugar metabolism in plants covers the synthesis, catabolism, utilization, and transformation of sugars in plants, including sucrose transport, signal transduction, and the synthesis of starch and cellulose (Kudo et al., 2023; Li et al., 2023b; Lo Piccolo et al., 2024). Sugar metabolism efficiently utilizes and regulates sugars, participates in plant adaptation to environmental changes, and provides energy for plant growth and development. Light influences sugar metabolism in plants through photosynthesis, sugar signaling, and photoperiod regulation, with changes in light conditions causing changes in plant metabolites (Lopes et al., 2024; Zhang et al., 2024). This review focuses on the effects of light on plant photosynthetic performance, growth and development, and sugar metabolism. The article also discusses the progress in research on the effects of light on plant physiological characteristics, with the aim of providing a theoretical basis for using light to regulate plant growth and improve yield and quality. The relationship between light and plant growth remains unclear and suggests potential research directions.
       Light has many properties, but its intensity and quality have the greatest impact on plants. Light intensity is commonly used to measure the brightness of a light source or the strength of a beam. Based on wavelength, light can be divided into ultraviolet, visible, and infrared. Visible light is further divided into red, orange, yellow, green, blue, indigo, and violet. Plants primarily absorb red and blue light as the primary energy for photosynthesis (Liang et al., 2021).
       However, the application of different light quality in the field, the control of photoperiod, and the effects of light intensity changes on plants are complex problems that need to be solved. Therefore, we believe that the rational use of light conditions can effectively promote the development of plant modeling ecology and the cascade use of materials and energy, thereby improving plant growth efficiency and environmental benefits. Using the ecological optimization theory, the adaptability of plant photosynthesis to medium- and long-term light is incorporated into the Earth system model to reduce the uncertainty of photosynthesis modeling and improve the accuracy of the model (Luo and Keenan, 2020). Plants tend to adapt to medium- and long-term light, and their photosynthetic capacity and light energy use efficiency in the medium- and long-term can be improved, thereby more effectively achieving ecological modeling of field cultivation. In addition, when applying field planting, the light intensity is adjusted according to the plant species and growth characteristics to promote healthy plant growth. At the same time, by adjusting the ratio of light quality and simulating the natural light cycle, it is possible to accelerate or slow down the flowering and fruiting of plants, thereby achieving more precise ecological regulation of field modeling.
       Light-regulated sugar metabolism in plants contributes to the improvement of plant growth and development, adaptation and resistance to environmental stress factors. Sugars, as signaling molecules, regulate plant growth and development by interacting with other signaling molecules (e.g., phytohormones), thereby influencing plant physiological processes (Mukarram et al., 2023). We believe that studying the regulatory mechanisms linking the light environment to plant growth and sugar metabolism will be an effective economic strategy to guide breeding and production practices. With the development of technology, future research on the selection of light sources, such as artificial lighting technologies and the use of LEDs, can be carried out to improve lighting efficiency and plant yield, providing more regulatory tools for plant growth and development research (Ngcobo and Bertling, 2024). However, red and blue light wavelengths are the most widely used in current research on the effects of light quality on plants. Thus, by investigating the effects of more diverse light qualities such as orange, yellow and green on plant growth and development, we can develop the mechanisms of action of multiple light sources on plants, thereby more effectively using different qualities of light in practical applications. This requires further study and improvement. Many processes of plant growth and development are regulated by phytochromes and phytohormones. Therefore, the influence of the interaction of spectral energy and endogenous substances on plant growth will be a key direction of future research. Moreover, in-depth study of the molecular mechanisms by which different light conditions affect plant growth and development, sugar metabolism, as well as the synergistic effects of multiple environmental factors on plants, will contribute to the further development and use of the potential of various plants, which will allow their application in such areas as agriculture and biomedicine.