Abstract:In this work, Soils with 1.25 g/cm3 (loose soil, CK) and 1.55 g/cm3 (compacted soil) bulk density were experimented on growing cucumber (Cucumis sativus L.) plants in pots. Effects of soil compaction stress on carbohydrate metabolism of leaves and roots of cucumber cultivar, Jinchun 4, at different growth and development stages were studied for discussing influence mechanism of soil compaction stress on cucumber growth. The results show that under the soil compaction stress, the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of cucumber leaves are decreased significantly, while the intercellular CO2 concentration (Ci) is increased markedly at different growth and development stages. Thereby, photosynthesis is hampered. The activity of sucrose phosphate synthase (SPS) of cucumber leaves is decreased significantly, while the sucrose synthase (SS), acid invertase (AI) and alkaline invertase (NI) activities are promoted remarkably in the compacted soil treatment. Furthermore, the contents of sucrose, glucose, fructose and starch are also increased markedly, and the synthesis and export of sucrose in leaves are restrained. In roots, the activities of SPS, AI and NI are decreased significantly, while the SS activity is obviously promoted. Moreover, the contents of sucrose, glucose and fructose are also increased strikingly, while the starch content is almost constant. These results indicate that under the soil compaction stress, the synthesis and export of photosynthate of source leaves are remarkably constrained, meanwhile, the import and utilization of carbohydrate of roots are reduced. As a result, the inhibition for plant growth and yield formation occur.