Abstract: To further study the effect of exogenous hydrogen sulfide (H₂S) on the physiological character of the radicle and its border cells of Pisum sativum, we investigated the variation in root tip and root border cells and other indexes after H₂S treatment at different concentrations. We measured root lengths, content of soluble protein in root tip tissues, antioxidant enzyme activities (APX, CAT, POD and SOD), survival rate of root border cells, and relative area of the mucilage layer. A low concentration of H₂S (0–40 μmol·L^–1) could increase the embryo root length of P. sativum; content of root tip soluble protein; activity of SOD, APX and POD; and survival rate of root border cells. This concentration decreased the activity of CAT and the relative area of the mucilage layer. When the concentration of H₂S was increased from 60 to 80 μmol·L^–1, embryo root length was reduced; content of soluble protein of root tips and survival rate of border cells were rapidly reduced; and activity of APX and POD was gradually reduced; but CAT activity was significantly increased, with no effect on SOD activity. Moreover, with improvement in relative area of the mucilage layer, the chromosomes of the root border cells were gradually condensed, marginalized and degraded; furthermore, the plasma membrane was condensed. Therefore, H₂S might have an important role in the physiological process of plants.

Key words: exogenous hydrogen sulfide, Pisum sativum, root border cells