Water hyacinth leaves in Nanjing show different patterns of photosynthesis throughout the day in summer. The highest photosynthetic rate occurs in June, with a single peak, while July and August have two peaks. Photosynthesis is inhibited at noon during summer. Stomatal conductance follows a similar pattern to photosynthesis. The 6th leaf has lower photosynthetic capacity than the 1st and 3rd leaves due to different developmental stages. Environmental factors like air temperature and light intensity affect the photosynthetic performance of water hyacinth.