What is the Difference Between Source and Sink in Plants?

The difference between source and sink in plants lies in their roles in the production and utilization of sugars. Here are the main distinctions between the two:

• Source: The source in a plant is responsible for synthesizing sugars required for plant growth. It typically refers to the photosynthetically active parts of the plant, such as the leaves and stems. In this context, the leaves act as a source when photosynthesizing and produce sugars for the plant.
• Sink: Sinks are the regions of the plant that are engaged in growth or serve as storage areas. They include plant parts like roots, stems, flowers, tubers, and bulbs. The sugars produced in the source are transported to the sinks for immediate use or storage for future metabolic needs.

In essence, the source is responsible for producing sugars through photosynthesis, while the sink utilizes these sugars for growth and storage. The phloem elements, which are responsible for transporting sugars in plants, are loaded at the source and unloaded at the sink.

It is important to note that a source is not always a source, and a sink is not always a sink. For example, leaves can act as sinks when the plant is young and in the growth phase, and stems and branches can act as sources when they are young and green, carrying out photosynthesis.

Comparative Table: Source vs Sink in Plants

The difference between source and sink in plants lies in their roles in phloem translocation, the process of transporting produced food (sucrose) in plants. Here is a table summarizing the key differences between source and sink in plants:

Sources and sinks in plants play crucial roles in the phloem translocation process. While sources are responsible for synthesizing sugars, sinks store the produced sugars. The transportation between source and sink depends on the osmotic pressure and takes place by mass flow.