Adaptations to nitrogen form: comparing inorganic nitrogen and amino acid availability and uptake by four temperate forest plants
Bibliographic record
Abstract
There are few examinations of the relative availability and plant uptake of inorganic N and amino acid N in temperate forest regions. We determined the availability of amino acid N and inorganic N in soils under two shrub species ( Vaccinium ovalifolium Sm. versus Rubus spectabilis Pursh) on three sites near Jordan River, British Columbia, over a growing season. We compared biomass production of the two shrubs and two conifers ( Picea sitchensis (Bong.) Carr. and Pseudotsuga menziesii (Mirb.) Franco var. menziesii) when given inorganic N (20:80 or 80:20 NH4+–NO3–) or organic N (glycine and glutamic acid) and assessed short-term uptake (24 h) of 15N-labelled NH4+, NO3–, glycine, or glutamic acid by the four species. Water-extracted soil concentrations of NH4+ were up to 1.5 times greater than NO3– averaged across sites. Concentrations of amino acid N and inorganic N were similar on soils under Rubus , but the amino acid N to inorganic N ratio was up to 2.4:1 in soils under Vaccinium . Soils dominated by Rubus had up to twice the NO3–-N and two thirds the amino acid N concentrations of soils dominated by Vaccinium, averaged across sites and Rubus had relatively high short-term 15NO3– uptake. The dry biomass of conifers was approximately four times greater when supplied mainly with NH4+ compared with NO3–, but biomass of the two shrub species was similar in both inorganic N treatments. All plants had comparable rates of short-term 15N uptake from amino acids and inorganic N, suggesting that amino acids could contribute to the N nutrition of these temperate species; however, dry biomass of all four species grown with amino acids was less than one half that of plants grown with inorganic N.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".