Article ID Journal Published Year Pages File Type
4750881 Review of Palaeobotany and Palynology 2009 8 Pages PDF
Abstract

Direct evidence for the origin and evolution of land plant/cyanobacterial symbioses is virtually absent from the fossil record. Here we report on rare occurrences of prostrate mycorrhizal axes of the Early Devonian land plant Aglaophyton major that host a filamentous cyanobacterium, which enters the plant through the stomata and colonizes the substomatal chambers and intercellular spaces in the outer cortex. In dead ends of the intercellular system, the filaments form loops and continue growth in reverse direction. Some filaments penetrate parenchyma cells close to and within the mycorrhizal arbuscule-zone and form intracellular coils. This discovery represents the earliest direct evidence for cyanobacteria growing inside land plants, and offers a model for the types of associations that may have preceded the evolution of mutualistic land plant/cyanobacterial symbioses.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Palaeontology
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