What is the main organ of photosynthesis and transpiration in higher plants?

The leaf is the main organ of photosynthesis and transpiration in higher plants due to its specialized structure and functions. Within the leaf, chloroplasts are abundant, which contain chlorophyll, the pigment essential for capturing sunlight. This absorption of light energy drives the photosynthetic process, where carbon dioxide from the air and water from the soil are converted into glucose and oxygen.

Additionally, leaves have a large surface area and are typically thin, optimizing light absorption and gas exchange through small openings called stomata. These stomata facilitate transpiration, the process by which water vapor is released from the plant into the atmosphere. This not only helps in nutrient transport but also affects temperature regulation within the plant.

In contrast, while stems can provide support and transport nutrients, roots primarily absorb water and minerals from the soil, and flowers are involved in reproduction rather than photosynthesis and transpiration. Thus, the leaf's unique adaptations make it the primary organ for both processes in higher plants.