Degradation of seed mucilage by soil microflora promotes early seedling growth of a desert sand dune plant

Authors

  • XUEJUN YANG,

    1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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  • CAROL C. BASKIN,

    1. Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA
    2. Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA
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  • JERRY M. BASKIN,

    1. Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA
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  • WENHAO ZHANG,

    1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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  • ZHENYING HUANG

    Corresponding author
    1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Z. Huang. Fax: +86 10 82595899; e-mail: zhenying@ibcas.ac.cn

ABSTRACT

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High-performance anion-exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO2 and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)-labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well-adapted.

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