Question

In plant, cell that transport water against the force of gravity are found to contain many more mitochondria than do some other plant cells. What is the reason for this

Answer 1

For this question I'm not too sure what you're asking because cells that transport water are basically xylem cells and these cells are hollow with nothing in them, and they transport water against gravity because of transpiration pull, capillary action and root pressure.
The cells that I know of with many mitochondria for transport would be the phloem so that the mitochondria can carry out cellular respiration to release energy for the translocation of sucrose.