Net carbon dioxide exchange rates in Pisum sativum L as influenced by phosphorus and nitrogen nutrition
Bibliographic record
Abstract
Two varieties of Pisum sativum, L, Jade and Olympic, were grown for a period of four weeks from seeding, under constant light intensity and diurnally fluctuating temperatures, while being subjected to varying-artificially induced-degrees of nutrient stress. Net carbon dioxide exchange rates were measured in order to determine the influence of excess or deficient nitrogen and phosphorus concentrations within the nutrient medium. Carbon dioxide assimilation rates, under various degrees of nutrient stress were highly variable, both within the same variety and between varieties tested. Microchemical determinations of chlorophylls a and b, and of inorganic phosphate, nitrate and nitrite were carried out in order to determine the relationship of some physiological aspects of mineral deficiency to carbon dioxide assimilation. Investigations as to changes in stomatal index (I) as a result of nutrient stress also showed a large amount of variation. Results obtained indicated that variety Jade was very sensitive to nitrogen deficiency within the rooting medium, as evidenced by a large increase in stomatal index values with nitrogen deficiency. Olympic showed a greater sensitivity to phosphorus deficiency than did Jade. Neither total chlorophyll content, nor chlorophyll a/b ratio appeared to exert any deciding influence upon net carbon dioxide assimilation. A relationship appeared to exist between CO₂ assimilation and quantities of nitrate and/or nitrite present within the photosynthetic tissues of plants tested. This experiment was unable to fully explain the reason(s) for the great degree of variability of net CO₂ exchange rates extant even between plant specimens growing in the same nutrient medium. Some technical improvements applicable to the present experiments as well as some alternative experimental procedures are discussed.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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".