Abstract Detail

Green Land: Multiple Perspectives on Green Algal Evolution and the Earliest Land Plants

Delwiche, Charles [1].

Assembling the Embryophyte Form: the Evolution of Streptophytes.

Knowledge of the earliest land plants and the environment they lived in remains incomplete, but exciting new insights are emerging. Plant spores are known from about 470 Ma (million years ago), while the earliest body fossils are substantially later, about 430 Ma. The Rhynie and Windyfield Cherts from Scotland are about 410 Ma, and spectacularly preserve complex plants with multiple tissue types, upright stems, apparently symbiotic associations with fungi, and diplohaplontic life cycles. There is every reason to think that in the preceding 60+ million years there was a developing terrestrial flora, but evidence of it is literally and figuratively fragmentary. One explanation for this appears to be the paucity of satisfactory environments for preservation. Remarkably, even mud in lacustrine environments appears to have been in large part an innovation stemming from the stabilization of soils produced by the growth of land plants. Complementing the fossil record are comparative molecular studies of living plants and their relatives (Streptophyte algae). Recent genomic studies have confirmed earlier ultrastructural and phylogenetic analyses, and have revealed that many processes previously assumed to be unique to embryophytes have much deeper roots in the Streptophyta. Fundamental aspects of metabolism, cell wall biochemistry, and hormone and signal transduction systems are all distinctly streptophyte in character. This has led to new interpretations of the distinction between ‘aquatic’ and ‘terrestrial’ in this lineage, but also illustrates the profound importance of the suite of characters that came together in the embryophytes and resulted in the modern terrestrial flora.

1 - University Of Maryland, CELL BIOLOGY AND MOLECULAR GENETICS, Biosciences Research Building, 4066 Campus Drive, College Park, MD, 20742, United States

Streptophyte algae

Presentation Type: Symposium Presentation
Number: 0003
Abstract ID:874
Candidate for Awards:None

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