Water transport through tomato roots infected with Meloidogyne incognita

The effect of Meloidogyne incognita on water flow in tomato roots was investigated in rooted split-stem cuttings. Total water flow through infected root parts was significantly lower than through comparable uninfected parts. Total water uptake was correlated with total length of the root system. In a root system severed from its stem and placed under a partial vacuum applied at the stem stump, the infected half transported significantly less water than its corresponding uninfected half. In perfusion chambers, infected apical, but not basal, root segments transported less water than adjacent uninfected segments. Axial resistance to water movement in galls at the root apex, but not at the base, increased. Cross sections of galls at the root base showed little effect on vascular continuity, but in terminal galls the number and diameter of xylem vessels were reduced.