Photosynthesis in rice plants responds to drought and high temperatures by oxidizing the chlorophyll in the photosystem I (PSI). This process is linked to a decrease in the efficiency of photosystems II and I, as well as a reduction in the primary electron acceptor of PSI. These responses are more pronounced at higher temperatures. While the oxidation of chlorophyll in PSI helps reduce harmful reactive oxygen species, severe stress conditions can still lead to damage in PSI.