Contact: Richard Hund
American Journal of Botany
Caption: This is reproductive Sphagnum peat moss, showing dark brown sporophytes that explosively discharge spores, perched on green gametophytes. Diverse species of this moss genus occur worldwide and dominate large areas of northern America, Europe, and boreal Asia where they generate vast peat accumulations, representing one of Earth's largest stores of organic carbon. Sphagnum growth is thus relevant to global carbon cycling and climate, and in turn is influenced by climate change. The pictured S. capillifolium was collected from a shaded location in Columbia County, Wisconsin. The research paper discussed in the press release demonstrates that laboratory cultures of S. compactum exhibit mixotrophic growth, that is, use exogenous sugars as a carbon source in addition to photosynthetic products, as do ecologically associated species of charophycean green algae. Mixotrophy is thus proposed to be an early-evolved trait in streptophytes and is suggested to aid survival under stressful conditions and subsidize the production of degradation-resistant cell walls that foster carbon sequestration. Composite of 18 focus-stacked images photographed with a Nikon D200 camera equipped with an AF Micro Nikkor 60 mm F2.8D lens (f8 at 1/5 sec). The images were stacked using Helicon Focus 4 software.
Credit: Image credit: Lee Wilcox, University of Wisconsin, Madison, Wisconsin.
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