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Terrestrial and Aquatic Ecology

1999

Tundra

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Full-Text Articles in Life Sciences

Soil Amino Acid Utilization Among Species Of The Cyperaceae: Plant And Soil Processes, Ted K. Raab, David A. Lipson, Steven K. Scmidt, Russ K. Monson Jan 1999

Soil Amino Acid Utilization Among Species Of The Cyperaceae: Plant And Soil Processes, Ted K. Raab, David A. Lipson, Steven K. Scmidt, Russ K. Monson

Ted K. Raab

Amino acids are released during the decomposition of soil organic matter and have been shown to be utilized as a nitrogen source by some non-mycorrhizal species in the family Cyperaceae (the sedge family). Twelve out of 13 Cyperaceae species examined in the current study were capable of absorbing soil amino acids in the non-mycorrhizal state. With two exceptions (two species in the genus Kobresia), species from subalpine or alpine habitats exhibited lower rates of total nitrogen uptake compared to species from more temperate habitats, which is possibly explained by lower growth rates in the alpine and subalpine species and a …


Variation In Competitive Abilities Of Plants And Microbes For Specific Amino Acids, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson Jan 1999

Variation In Competitive Abilities Of Plants And Microbes For Specific Amino Acids, David A. Lipson, Ted K. Raab, Steven K. Schmidt, Russ K. Monson

Ted K. Raab

Microbes are assumed to possess strong competitive advantages over plants for uptake of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a significant fraction of their N requirement from soil amino acids contradicts this assumption. The amino acid glycine (Gly) has been used as a model amino acid in many recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial growth compared to other amino acids. We tested the hypothesis that the alpine sedge Kobresia myosuroides competes better for Gly than for other amino acids because of decreased microbial demand for this compound. …