Final answer:
The specific leaf area (SLA) is the component of relative growth rate that represents the leaf area per unit of plant weight, indicating the efficiency of resource use by plants.
Step-by-step explanation:
The component of relative growth rate that represents the leaf area per unit of plant weight is called the specific leaf area (SLA).
Specific leaf area is calculated by dividing the leaf area by the plant weight. It is a measure of the efficiency with which plants use resources, as a higher SLA indicates that a plant can produce more leaf area per unit of weight, allowing for greater photosynthesis and growth.
For example, plants with a high SLA, such as some fast-growing annuals, have thinner leaves and are able to capture more light energy for photosynthesis, resulting in a higher growth rate.