Abstract: To study the changes in tissue structures and resistance mechanisms that occur due to the interaction between peach roots and root knot nematodes，seedlings of the resistant Baigen Gansu Tao 1 （Prunus kansuensis）and the susceptible Bailey（P. persica）were inoculated with Meloidogyne incognita using artificial indoor inoculation. Root tips were observed by staining at 6，12，18，24，30，36，42 and 48 h after inoculation，and the tissue structure of the root tips was observed by paraffin section at 0，6，12，36，60 and 84 h after inoculation. Staining results showed that the infection law of Baigen Gansu Tao 1 and Bailey were roughly similar：Root knot nematodes began invading at 12 h after inoculation，and the number of root knot nematodes increased gradually during the period between 12 h to 30 h after inoculation. The number of root knot nematodes present in the roots subsequently decreased as theorganisms began their upward movement along the plants’ vascular bundles. Compared to Bailey，at 30 h after inoculation Baigen Gansu Tao 1 were infected with root knot nematodes at a significantly lower rate：Only 28% of that of Bailey. Paraffin section results showed that the structural damage to inoculated Baigen Gansu Tao 1 was much less severe than in inoculated Bailey. Nematodes gathered in certain areas，which led to cells necrosis at the gathering sites at 84 h after inoculation.

Key words: peach, Meloidogyne incognita, root, anatomical structure, resistance mechanism