Final answer:
The fertilizer should target the meristematic tissues, which are responsible for plant growth through rapid cell division. These tissues are found at the tips of roots and shoots as well as in the cambium layer of plants.
Step-by-step explanation:
You are measuring the effect of a new fertilizer on the growth of lawns, and the tissue that should be the target of the fertilizer is the meristematic tissue. Meristematic tissues are regions in plants where rapid cell division occurs, leading to growth. They are responsible for both primary and secondary growth in plants, with primary growth occurring at the tips of roots and shoots (increasing the length) and secondary growth related to an increase in girth (seen in woody plants).
Meristematic tissue differentiates into three main types: dermal, vascular, and ground tissues. However, since you're interested in enhancing growth, the meristematic tissues at the tips of roots and shoots (apical meristems) and in the cambium layer (lateral meristems) are the most relevant for promoting growth in response to fertilizer.