The effects of biodiversity gradient on plant mass and metabolism of individual submerged macrophytes

Abstract Background The effects of biodiversity on community function and services are frequently studied in the history of ecology, while the response of individual species to biodiversity remains great elusive. In this study, we determined the biodiversity effects on community productivity as well as species level plant mass and carbon (C) and nitrogen (N) metabolism of eight submerged plants. These macrophytes in Lake Erhai were selected and planted in a water depth of one meter along a diversity gradient of 1, 2, 4 or 8 species. Then, the community productivity or species level plant mass, soluble protein, free amino acid and soluble carbohydrate were correlated to species richness to determine the biodiversity effects on community and single species. Results The results showed that the community level biomass was positively correlated to plant species richness although the species level plant mass of individual species responded differently to the overall plant species richness. Namely, only one plant mass positively correlated to species richness and the others decreased or showed no significant correlation with the increase of species richness. The soluble proteins of most macrophytes were positively correlated to species richness; however, both the free amino acid and soluble carbohydrate of the plants were negatively or not significantly correlated to species richness. Conclusions These results indicated that the selection effects might dominate in our aquatic communities and the negative impacts of biodiversity on C and N metabolism of the macrophytes increased with the increase of species richness, which might result from the strong competition among the studied species. The biodiversity effects on the plant mass, and C and N metabolism of individual submerged species were first reported in this study, while more such field and control experiments deserve further research.

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Amino acid fingerprint of a grassland soil reflects changes in plant species richness

Plant and Soil ◽

10.1007/s11104-010-0387-1 ◽

2010 ◽

Vol 334 (1-2) ◽

pp. 353-363 ◽

Cited By ~ 19

Author(s):

Leopold Sauheitl ◽

Bruno Glaser ◽

Michaela Dippold ◽

Katharina Leiber ◽

Alexandra Weigelt

Keyword(s):

Species Richness ◽

Amino Acid ◽

Plant Species ◽

Plant Species Richness ◽

Grassland Soil

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Hepatic detoxification of ammonia in the ovine liver: possible consequences for amino acid catabolism

British Journal Of Nutrition ◽

10.1079/bjn19950072 ◽

1995 ◽

Vol 73 (5) ◽

pp. 667-685 ◽

Cited By ~ 140

Author(s):

G. E. Lobley ◽

A. Connell ◽

M. A. Lomax ◽

D. S. Brown ◽

E. Milne ◽

...

Keyword(s):

Amino Acid ◽

Kinetic Data ◽

Free Amino ◽

Liver Blood Flow ◽

Whole Body ◽

Acid Oxidation ◽

Urea Synthesis ◽

Amino Acid Oxidation ◽

N Metabolism ◽

Glutamate Synthesis

The effects of either low (25 μmol/min) or high (235 μmol/min) infusion of NH4Cl into the mesenteric vein for 5 d were determined on O2consumption plus urea and amino acid transfers across the portal-drained viscera (PDV) and liver of young sheep. Kinetic transfers were followed by use of15NH4Cl for 10 h on the fifth day with simultaneous infusion of [1-13C]lleucine to monitor amino acid oxidation. Neither PDV nor liver blood flow were affected by the additional NH3loading, although at the higher rate there was a trend for increased liver O2consumption. NH3-N extraction by the liver accounted for 64–70% of urea-N synthesis and at the lower infusion rate the additional N required could be more than accounted for by hepatic removal of free amino acids. At the higher rate of NH3administration additional sources of N were apparently required to account fully for urea synthesis. Protein synthesis rates in the PDV and liver were unaffected by NH3infusion but both whole-body (P< 0·05) and splanchnic tissue leucine oxidation were elevated at the higher rate of administration. Substantial synthesis of [15N]glutamine occurred across the liver, particularly with the greater NH3supply, and enrichments exceeded considerably those of glutamate. The [15N]urea synthesized was predominantly as the single labelled, i.e. [14N15N], species. These various kinetic data are compatible with the action of ovine hepatic glutamate dehydrogenase (EC1.4.1.2) in periportal hepatocytes in the direction favouring glutamate deamination. Glutamate synthesis and uptake is probably confined to the perivenous cells which do not synthesize urea. The implications of NH3detoxification to the energy and N metabolism of the ruminant are discussed.

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Arginine and the shade tolerance of white spruce saplings entering winter dormancy

Journal of Forest Science ◽

10.17221/57/2009-jfs ◽

2010 ◽

Vol 56 (No. 2) ◽

pp. 77-83 ◽

Cited By ~ 5

Author(s):

J. Durzan D

Keyword(s):

Amino Acid ◽

Free Amino ◽

Shade Tolerance ◽

Growth Habit ◽

White Spruce ◽

Carbon Gain ◽

Natural Light ◽

Winter Dormancy ◽

Guanidino Compounds ◽

N Metabolism

Shade-tolerant white spruce saplings grown at 100, 45, 25, and 13% natural light for four years, and entering winter dormancy, modified their growth habit and redistributed the total soluble N among needles, roots, and stems with buds mainly to arginine N. Most free amino acid N was found in roots in saplings at full light, and the least at 13% light. Glutamate, glutamine, and aspartate N contributed to the accumulation of soluble arginine N. Arginine-derived γ-guanidinobutyric acid, agmatine and an unidentified guanidino compound accumulated mainly in stems with buds at 25 and 13% light. The profiling N metabolism and arginine-derived guanidino compounds extend models for shade tolerance based mainly on photosynthesis, respiration and carbon gain.

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