It can also be seen from Table 3 that the cat content of all groups increased with the prolongation of zinc treatment time and the increase of zinc concentration. But the increase of cat in zinc treatment group was significantly higher than that in control group. The results showed that with the increase of zinc concentration and zinc treatment time, the cat content of Dendrobium nobile increased significantly, which may be due to the large amount of hydrogen peroxide produced byDendrobium nobile under the stimulation of zinc.