Genomics and Applied Biology 2024, Vol.15, No.6, 285-295 http://bioscipublisher.com/index.php/gab 291 6 Environmental and Physiological Influences on Photosynthesis in Sweet Potato 6.1 Effects of light intensity and quality Light intensity and quality significantly influence the photosynthetic efficiency and overall growth of sweet potato. Shading experiments have shown that reduced light conditions can decrease the net photosynthetic rate, soluble sugar, starch, and sucrose content in sweet potato leaves. However, moderate shading (30%-50%) can increase chlorophyll concentrations and enhance the efficiency of light interception and absorption, which may help the plant adapt to low light environments (Jing et al., 2023). Additionally, the expression of genes related to photosynthesis and chlorophyll synthesis is upregulated under shading, indicating a complex regulatory mechanism to optimize light utilization. 6.2 Impact of temperature and water availability Temperature and water availability are critical factors affecting photosynthesis in sweet potato. High temperatures can cause photo-oxidative damage to the photosynthetic machinery, but the Orange gene (IbOr) in sweet potato helps maintain carotenoid homeostasis and stabilizes photosystem II, thereby enhancing tolerance to heat stress (Kim et al., 2018). Water availability also plays a crucial role; drought conditions can reduce photosynthetic rates and water use efficiency. However, overexpression of certain genes, such as BBX21, can improve photosynthesis and water use efficiency under moderate drought by enhancing mesophyll conductance and electron transport capacity (Ocampo et al., 2021). Additionally, the StCDF1-StFLORE locus in potato, which regulates water loss and stomatal conductance, highlights the importance of genetic factors in managing water use under drought conditions (Gonzales et al., 2020). 6.3 Interaction of genetic regulation with environmental factors Epigenetic regulation plays a significant role in the adaptation of photosynthesis to environmental changes. Epigenetic mechanisms, such as histone acetylation and DNA demethylation, mediate the expression of key photosynthetic genes like RuBisCO and PEPC in response to light, temperature, and drought conditions. For instance, euchromatin configuration can enhance drought tolerance by optimizing stomatal conductance and gas exchange, suggesting that epigenetic modifications are crucial for photosynthetic plasticity and stress adaptation (Duarte-Aké et al., 2019). Additionally, the overexpression of epigenetic modifiers like StMSI1 and StE[z]2 in potato has been shown to induce tuber formation and improve plant architecture under varying photoperiods, further emphasizing the role of epigenetics in environmental adaptation (Kondhare et al., 2021). The interaction between genetic regulation and environmental factors significantly impacts the yield of sweet potato. Overexpression of the H+-pyrophosphatase gene (IbVP1) in sweet potato enhances photosynthesis and sucrose content in leaves, leading to increased starch content and total yield in storage roots (Fan et al., 2021). Similarly, the BBX21 gene improves photosynthetic rates and water use efficiency under drought conditions, resulting in higher tuber yield (Ocampo et al., 2021). However, not all genetic modifications lead to positive outcomes; for example, the overexpression of VPZ genes in potato, which accelerates non-photochemical quenching, did not improve photosynthetic rates or yield under fluctuating light conditions, highlighting the complexity of genetic-environmental interactions (Lehretz et al., 2022). These findings underscore the importance of understanding and optimizing genetic regulation to enhance crop yield under diverse environmental conditions. 7 Prospects and Future Directions 7.1 Emerging technologies in photosynthesis research Recent advancements in photosynthesis research have opened new avenues for enhancing the efficiency of this critical process in sweet potatoes. One promising approach involves the use of kinetic modeling to identify and optimize key photosynthetic enzymes. For instance, a study on potato demonstrated that manipulating the expression of enzymes such as Rubisco, FBP aldolase, and SBPase could significantly increase photosynthetic rates, suggesting similar strategies could be applied to sweet potatoes (Vijayakumar et al., 2023). Additionally, the heterologous expression of transcription factors like AtBBX21 has shown potential in improving photosynthetic efficiency and reducing photoinhibition under high-irradiance conditions, which could be beneficial for sweet
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