Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which component of the plant is involved in increasing transpiration rates?

1. Photosynthesis

2. Xylem

3. Chloroplast

4. Ovary

The correct answer is: Xylem

The xylem plays a critical role in increasing transpiration rates within plants. It is the tissue responsible for transporting water and dissolved minerals from the roots to the rest of the plant. As water is taken up from the soil and moved through the xylem, it provides the moisture necessary for the process of transpiration, where water evaporates from the surface of leaves through tiny openings called stomata. This evaporation creates a negative pressure in the xylem, which facilitates the upward movement of more water from the roots. Additionally, the xylem structure, which consists of hollow tubes, allows for this efficient movement of water under tension, supporting the overall transpiration process. Therefore, the xylem directly influences the rate of transpiration by ensuring a constant supply of water to replace what is lost, thereby enhancing the plant's ability to cool itself and maintain nutrient uptake. Other components mentioned, like photosynthesis and chloroplasts, are related to energy production and gas exchange, while the ovary is involved in reproduction, and none directly increase transpiration rates.