Answer
Other factors affecting transport through tracheids would include the availability of water, the ability of the root to take up water (for example, are root hairs present on the root), the presence of mycorrhizal associations, the efficiency of water uptake into the vascular tissue.
Work Step by Step
Here, the key is to look at what affects water uptake other than the diameter of xylem cells. This includes the ability of the plant to absorb water and get it to the xylem and the overall amount of water available in the soil.