Cytosolic alkalization-mediated H<sub>2</sub>O<sub>2</sub> and NO production are involved in darkness-induced stomatal closure in <i>Vicia faba</i>
Bibliographic record
Abstract
Ma, Y., She, X. and Yang, S. 2013. Cytosolic alkalization-mediated H 2 O 2 and NO production are involved in darkness-induced stomatal closure in Vicia faba. Can. J. Plant Sci. 93: 119–130. Darkness raised cytosolic pH, hydrogen peroxide (H2O2) and nitric oxide (NO) levels in guard cells while inducing Vicia faba stomatal closure. These darkness effects were prevented by weak acid butyric acid, H2O2 modulators ascorbic acid (ASA), catalase (CAT), diphenyleneiodonium (DPI) and NO modulators 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), NG-nitro-L-arg-methyl ester (L-NAME) respectively. The data suggest that cytosolic alkalization, H2O2 and NO all participate in darkness-induced stomatal closure. During darkness treatment, pH rise became noticeable at 10 min and peaked at 25 min, while H2O2 and NO production increased significantly at 20 min and reached their maximums at 40 min. The H2O2 and NO levels were increased by methylamine in light and decreased by butyric acid in darkness. The results show that cytosolic alkalization induces H2O2 and NO production. ASA, CAT and DPI suppressed NO production by methylamine, c-PTIO and L-NAME prevented H2O2 generation by methylamine. Calcium chelator 1,2-bis (2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM) and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) restricted darkness-induced alkalization, H2O2 and NO production and stomatal closure. We suggest that cytosolic alkalization is necessary for H2O2 and NO production during darkness-induced stomatal closure. H2O2 mediates NO synthesis by alkalization, and vice versa. Calcium may act upstream of cytosolic alkalization, H2O2 and NO production, besides its known action downstream of H2O2 and NO.
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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) | 0.001 | 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 | 0.001 |
| 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".