Explain: The relationship between source and sink is variable.

(N/A) The $source$ is defined as the part of the plant that synthesizes food,such as leaves.
The $sink$ is the part of the plant that needs or stores food.
However,the relationship between $source$ and $sink$ is not fixed and can change depending on the season or the plant's needs.
For example,sugars stored in roots during winter act as a $source$ at the beginning of spring.
- At this time,the developing buds of the plant act as the $sink$.
- Energy is required for the growth and development of new photosynthetic parts.
- Thus,the relationship between $source$ and $sink$ is variable.