photosynthesisdecaying

Photosynthesis decaying refers to the progressive decline in a plant's or photosynthetic system's capacity to convert light energy into chemical energy. This phenomenon can arise from natural aging of leaves, pigment degradation, or damage to the photosynthetic apparatus, leading to a reduction in net photosynthetic rates over time or under environmental stress.

Causes include leaf senescence, nutrient limitations (particularly nitrogen and magnesium), drought and salinity, high light intensity that causes photoinhibition, heat stress, and biotic factors such as pathogens or ozone. Mechanistically, decaying photosynthesis involves loss of chlorophyll and carotenoids, reduced Rubisco content or activity, damage to photosystem II components (notably the D1 protein), and increased nonphotochemical quenching that limits photochemistry. Stomatal closure under drought further lowers CO2 availability.

Researchers assess decay with measurements such as net CO2 assimilation rate, stomatal conductance, and chlorophyll fluorescence parameters (e.g., Fv/Fm, ΦPSII). Pigment analysis tracks chlorophyll and carotenoid concentrations, while time-course experiments reveal decay kinetics and recovery potential after stress relief.

Implications include lower plant growth and yields, altered carbon balance in ecosystems, and changes in seasonal productivity. In engineered or artificial photosynthesis systems, decaying performance can reflect catalyst degradation, electrode corrosion, or pigment or semiconductor deterioration, highlighting the need for protective materials, efficient heat management, and robust design. Mitigation focuses on adequate nutrition, water management, shading or temperature control, and breeding or engineering for stress-resistant photosynthetic machinery.