How Do Environmental Conditions Modulate the Ecophysiological and Biochemical Responses of C3, C4, and CAM Plants in Different Cropping Systems?

Climate change has intensified abiotic stresses, including water deficit, high temperatures, excessive radiation, and their interactions, compromising plant growth, photosynthesis, and agricultural productivity, particularly in arid and semi-arid regions. Understanding the adaptive mechanisms associated with different photosynthetic pathways is therefore essential for developing resilient agricultural systems. This review discusses the ecophysiological fundamentals of C3, C4, and crassulacean acid metabolism (CAM) plants, focusing on their physiological, photochemical, and biochemical responses to abiotic stresses and management strategies for mitigating environmental impacts. C3 plants are more sensitive to stomatal limitation and increased photorespiration under stress, whereas C4 species benefit from carbon-concentrating mechanisms that enhance photosynthetic efficiency under high temperatures. CAM plants exhibit high water-use efficiency through temporal separation of carbon assimilation but may be vulnerable to extreme heat because of limited evaporative cooling. Across pathways, reduced carbon assimilation can cause photochemical imbalance and reactive oxygen species accumulation, activating antioxidant and osmotic responses. Management practices, including intercropping, rational irrigation, soil cover, balanced fertilization, plant density, and spatial arrangement, can modify the microenvironment and physiological responses. Integrating species with contrasting photosynthetic pathways may improve water, light, and nutrient use through complementarity, although competition can limit these benefits. Further research should address combined stresses and interactions among management strategies to improve crop resilience under climate change.