How does sugar collect in ripening tomatoes?

Sugars are transported to ripening tomato fruit from the leaves where they are synthesized. This transport occurs through the phloem, which is a specialized tissue that transports sugars and other nutrients throughout the plant.

1. Phloem transport: The phloem is a network of specialized cells that transports sugars and other nutrients throughout the plant. These sugars are produced in the leaves of the plant through the process of photosynthesis, where sunlight converts carbon dioxide and water into sugar and oxygen. The sugars produced by photosynthesis are then transported through the phloem to different parts of the plant, including the fruit.

2. Accumulation in the fruit: As the tomato fruit ripens, it begins to accumulate sugars transported from the leaves. The ripening process is triggered by the production of ethylene, a plant hormone that plays a role in fruit ripening and senescence. Ethylene stimulates the breakdown of starch and other complex carbohydrates into simple sugars, such as glucose and fructose, which are then transported to the fruit.

3. Storage in the vacuoles: Inside the tomato fruit, the sugars are stored in the vacuoles of the fruit cells. Vacuoles are small organelles that serve as storage compartments within the cells. The accumulation of sugars in the vacuoles contributes to the sweetness and flavor of the ripe tomato.

The accumulation of sugars in ripening tomatoes is a critical process that results from the transport of sugars from the leaves and their storage in the fruit vacuoles. This process is essential for the development of the characteristic sweet flavor and overall quality of the ripe tomatoes.