Variation in the kcat of Rubisco in C3 and C4 plants and some implications for photosynthetic performance at high and low temperature
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The capacity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) to consume RuBP is a major limitation on the rate of net CO(2) assimilation (A) in C(3) and C(4) plants. The pattern of Rubisco limitation differs between the two photosynthetic types, as shown by comparisons of temperature and CO(2) responses of A and Rubisco activity from C(3) and C(4) species. In C(3) species, Rubisco capacity is the primary limitation on A at light saturation and CO(2) concentrations below the current atmospheric value of 37 Pa, particularly near the temperature optimum. Below 20 degrees C, C(3) photosynthesis at 37 and 68 Pa is often limited by the capacity to regenerate phosphate for photophosphorylation. In C(4) plants, the Rubisco capacity is equivalent to A below 18 degrees C, but exceeds the photosynthetic capacity above 25 degrees C, indicating that Rubisco is an important limitation at cool but not warm temperatures. A comparison of the catalytic efficiency of Rubisco (k(cat) in mol CO(2) mol(-1) Rubisco active sites s(-1)) from 17 C(3) and C(4) plants showed that Rubisco from C(4) species, and C(3) species originating in cool environments, had higher k(cat) than Rubisco from C(3) species originating in warm environments. This indicates that Rubisco evolved to improve performance in the environment that plants normally experience. In C(4) plants, and C(3) species from cool environments, Rubisco often operates near CO(2) saturation, so that increases in k(cat) would enhance A. In warm-habitat C(4) species, Rubisco often operates at CO(2) concentrations below the K(m) for CO(2). Because k(cat) and K(m) vary proportionally, the low k(cat) indicates that Rubisco has been modified in a manner that reduces K(m) and thus increases the affinity for CO(2) in C(3) species from warm climates.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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) | 0.000 | 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 it