If the xylem vessels of a plant are plugged:

1. The leaves will turn yellow
2. No food will be made
3. The plant will wilt (shrivel)
4. The plant will continue to grow

The plant will wilt (shrivel)

Reason — The xylem vessels of the plant are responsible for the conduction of water and mineral salts in the plant body. So, if the xylem vessels of the plant are plugged, the transport of water will stop and the plant will wilt.
Yellowing of leaves (chlorosis) usually happens due to lack of nutrients like nitrogen or magnesium, not directly due to blockage of xylem. Food (glucose) is made in leaves by photosynthesis. While water is needed, xylem blockage does not immediately stop food production completely—it mainly affects water supply first. Without water transport, essential processes stop, so the plant cannot grow properly.