Possible causes of slow growth of nitrate-supplied<i>Pinus pinaster</i>
Bibliographic record
Abstract
We investigated possible causes of slower growth of Pinus pinaster Ait. supplied with nitrate, as compared with ammonium or with ammonium nitrate mixtures. Six-month-old mycorrhizal seedlings of P. pinaster were grown in sand culture for 4 months at four concentrations of N (0.125, 0.5, 2.0, or 8.0 mM) as nitrate or ammonium or with an ammoniumnitrate mixture at 0.125 or 2.0 mM. After 4 months of nutrient addition, we measured light-saturated rates of photosynthesis (A max ), rates of ammonium and nitrate uptake, growth, macro- and micro-elements, and patterns of N allocation in needles. Dry mass was unaffected by N form at 0.125 or 0.5 mM N. In contrast, dry mass of seedlings supplied with ammonium or ammonium nitrate at 2.0 and 8.0 mM N, was approximately threefold greater than seedlings supplied with nitrate alone. Concentrations of N in foliage and A max were unaffected by the form or concentration of N supplied. Furthermore, concentrations of amino acid N were greater in seedlings supplied with nitrate, suggesting rates of uptake were not limiting growth. Foliage concentrations of zinc were low with nitrate supplied at a concentration of 0.5 mM or greater, and seedlings displayed symptoms typical of zinc deficiency when nitrate was supplied at 2.0 or 8.0 mM. Slower growth with nitrate could not be explained solely by either slower root uptake of nitrate N or lesser A max . Instead, aspects of N metabolism postuptake coupled with other factors such as nutrient deficiencies may limit growth with nitrate as the sole N source.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".