Soil microbes and seed mucilage promote growth of the desert ephemeral plant Nepeta micrantha under different water conditions

Abstract

Ephemeral plants, which can complete their life cycle in two to three months, play an important role in stabilizing sand dune surfaces from wind erosion in spring in the Gurbantunggut Desert, northwestern China. Soil microbes and seed mucilage could promote seedling growth of desert species via independent effects and / or interactions. However, it is uncertain whether both factors affect growth of adult ephemeral plants when exposed to different water regimes. Intact or demucilaged seeds of Nepeta micrantha were sown in sterile and non-sterile soil and exposed to three water regimes. The results indicated that plants under middle water treatment had higher dry mass accumulation as compared to that under low and high water treatments. Soil microbes and seed mucilage could significantly increase plant growth in all three water regimes. Their interactions showed positive effect on growth only under low water treatment. Nepeta micrantha plants had the highest biomass in the treatment of intact seeds in non-sterile soil and exposed to middle water regimes. Our study provides a better understanding of the growth regulation mechanism by which water, soil microbes and seed mucilage interactively promote growth of ephemeral plants in arid desert.