RESUMEN
Arbuscular mycorrhizal (AM) symbiosis can play a role in improving seedling establishment in deserts, and it has been suggested that achene mucilage facilitates seedling establishment in sandy deserts and that mucilage biodegradation products may improve seedling growth. We aimed to determine if AM symbiosis interacts with achene mucilage in regulating seedling growth in sand dunes. Up to 20 A M fungal taxa colonized Artemisia sphaerocephala roots in the field, and mycorrhizal frequency and colonization intensity exhibited seasonal dynamics. In the greenhouse, total biomass of AM fungal-colonized plants decreased, whereas the root/shoot ratio increased. AM symbiosis resulted in increased concentrations of nutrients and chlorophyll and decreased concentrations of salicylic acid (SA) and abscisic acid (ABA). Achene mucilage had a weaker effect on biomass and on nutrient, chlorophyll, and phytohormone concentration than did AM symbiosis. We suggest that AM symbiosis and achene mucilage act independently in enhancing seedling establishment in sandy deserts.
Asunto(s)
Artemisia/crecimiento & desarrollo , Frutas/fisiología , Micorrizas/fisiología , Mucílago de Planta/fisiología , Simbiosis/fisiología , Artemisia/genética , Artemisia/microbiología , Artemisia/fisiología , Aspergillus niger/genética , Aspergillus niger/fisiología , Clorofila/metabolismo , ADN de Hongos/genética , ADN de Plantas/genética , Clima Desértico , Frutas/metabolismo , Micorrizas/genética , Filogenia , Reguladores del Crecimiento de las Plantas/fisiología , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Reacción en Cadena de la Polimerasa , Ácido Salicílico/metabolismo , Plantones/crecimiento & desarrollo , Plantones/microbiología , Análisis de Secuencia de ADNRESUMEN
Seedling emergence is a critical stage in the establishment of desert plants. Soil microbes participate in plant growth and development, but information is lacking with regard to the role of microbes on seedling emergence. We applied the biocides (captan and streptomycin) to assess how seed mucilage interacts with soil microbial community and physiochemical processes to affect seedling emergence of Artemisia sphaerocephala on the desert sand dune. Fungal and bacterial community composition and diversity and fungal-bacterial interactions were changed by both captan and streptomycin. Mucilage increased soil enzyme activities and fungal-bacterial interactions. Highest seedling emergence occurred under streptomycin and mucilage treatment. Members of the phyla Firmicutes and Glomeromycota were the keystone species that improved A. sphaerocephala seedling emergence, by increasing resistance of young seedlings to drought and pathogen. Seed mucilage directly improved seedling emergence and indirectly interacted with the soil microbial community through strengthening fungal-bacterial interactions and providing favourable environment for soil enzymes to affect seedling emergence. Our study provides a comprehensive understanding of the regulatory mechanisms by which soil microbial community and seed mucilage interactively promote successful establishment of populations of desert plants on the barren and stressful sand dune.