Distribution of soil seed reserve and its association with aboveground vegetation in salinized soils of arid regions in northwest China

摘要

The seed bank of salinized soil is a valuable germplasm resource for plant salt tolerance research. The study collected 468 soil samples from plant communities of 5 subtypes and 13 soil genera in saline-sodic badland of northwest China in spring, summer, and autumn, 2015, respectively. The seed from the soil samples was germinated in lab and species were identified. There were 34 species from 14 families and 31 genera that mainly belong to Chenopodiaceae, Gramineae, and Compositae. However, identification of the aboveground vegetations found that there were 21 species from 9 families and 19 genera that mainly belong to Chenopodiaceae and Poaceae. The difference in species between the aboveground vegetation and the soil seed bank was mainly in herbaceous plants, which had strong adaptability to salinity and alkalinity. The soil seed reserves were small and simple in species composition, with most species being indicator halophytes of desert. In spring, summer, and autumn, soil seed densities in the 5 subtypes of saline soil decreased in the order of meadow solonchaks orthic solonchaks dry solonchaks bog solonchaks alkalized solonchak. However, there was no significant difference in soil seed density between spring, summer and autumn. Soil seed bank showed a significant vertical hierarchy. The correlation between soil seed bank and aboveground vegetation is small in salinized and arid regions.