Ion homeostasis and salinity tolerance in Arabidopsis thaliana: roles for the vacuolar Na+/H+ antiporter, AtNHX1
Bibliographic record
Abstract
Na+/H+ antiporters play a major role in pH and ion homeostasis of cells throughout the biological kingdom. At the plant vacuolar membrane, these antiports use the energy available in the electrochemical gradient of protons to regulate the steady-state ion distribution between the cytosol and the endomembranal compartments. This ion distribution and the concomitant ion homeostasis are essential for the regulation of key physiological processes such as cell expansion and the regulation of cytosolic pH. This thesis describes the cloning and initial characterization of a family of Na +/H+ antiporters in Arabidopsis thaliana. Experiments using overexpression and T-DNA insertional mutants of one of the members of this family, AtNHX1, confirmed the paramount role of vacuolar Na+ compartmentation in the tolerance of plants to salinity and enabled the in planta characterization of AtNHX1 activity. For example, the accumulation of Na+ in plants overexpressing vacuolar Na+/H+ antiporters was greater than that in wild-type plants, which was in turn, greater than that shown in nhx1 plants. The severe reduction of AtNHX1 function appears to have an effect on leaf development, which is also related to cell expansion, the maintenance of turgor, and K+ homeostasis. Moreover, the dramatic reduction in K+-dependent H+ efflux in vacuoles isolated from nhx1 leaves confirmed the role of AtNHX1 as the dominant cation/H+ antiport in leaves.
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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".