[Effects of soil compactness stress on root activity and leaf photosynthesis of cucumber]

Responses of root activity and leaf photosynthesis to soil compactness stress were studied in cucumber plants grown in pots. Soil compaction was expressed by soil bulk density. There were three compactness treatments with soil bulk densities, 1.2, 1.4 and 1.6 g/cm(3). The results showed that when the soil compactness increased, the dry weight and activity of roots reduced (Fig. 1); the relative electrical conductivity and malondialdehyde (MDA) content of cucumber leaf (Fig. 2) increased; the soluble protein content decreased (Fig. 3); the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased (Fig. 4); net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E) and specific leaf weight (SLW) decreased, but intercellular CO(2) concentration (Ci) increased (Fig. 5). These results mean that high soil compaction brings stress to cucumber plants.