What is the green substance in plants that is crucial for photosynthesis?

The green substance in plants that is crucial for photosynthesis is chlorophyll. This pigment is vital because it absorbs light energy from the sun, primarily in the blue and red wavelengths, and converts it into chemical energy during the photosynthesis process. Chlorophyll is predominantly found in the chloroplasts of plant cells, which are the specific organelles where photosynthesis occurs.

The presence of chlorophyll is what gives plants their green color and is fundamental to the ability of plants to make their own food by converting carbon dioxide and water into glucose and oxygen using solar energy. This process not only sustains the plant itself but also provides oxygen and serves as the basis for food chains in ecosystems. Other substances mentioned, like xanthophyll and carotene, are accessory pigments that can also play roles in light absorption but are not the main pigment responsible for photosynthesis. Stomata are pores in the leaves that facilitate gas exchange but are not responsible for photosynthesis directly.