The roles of suberin biopolymer and associated waxes in protecting plants against abiotic stresses
Bibliographic record
Abstract
Plants have various hydrophobic barriers that protect against environmental stresses.Suberin is one such extracellular lipid-based barrier that is deposited in various tissues in terrestrial plants.It is a complex aliphatic and aromatic heteropolymer that plays important roles in controlling water and ion movement.The precise roles of suberin in defending against abiotic stresses (e.g.drought, salinity and heavy metals) and the defensive mechanisms are currently unknown.A better understanding of these protective functions could provide information on novel genetic approaches to manipulate suberin for the development of stress tolerant crops.In this thesis, I explore some of the specific roles of root suberin and seed coat suberin in the model plant Arabidopsis thaliana in relation to abiotic stress tolerance.Physio-chemical responses and stress tolerance as a result of alterations in suberin were investigated using several suberin-altered mutants of Arabidopsis thaliana.Drought-induced suberin reduced water loss through the root periderm.The amount of water loss in roots was inversely correlated to the amount of total suberin.Suberin lamellae structure was important in reducing water loss under drought stress.Salt stress responses in suberin-altered mutants indicate suberin composition or lamellae structure are essential in barrier function of root suberin against uncontrolled transport of Na into the shoot.Mutants of Arabidopsis defective in various seed coat polymeric substances (suberin, cutin, mucilage, or proanthocyanidins) were tested for changes in germination and viability after stratification and imbibition in a range of mining environment-relevant chromium Cr(III) concentrations.Seeds reduced in total seed coat suberin were strongly affected by increasing Cr 3+ concentrations, affecting both germination and embryo viability.This provides evidence for ii the effective barrier function of seed coat suberin on the imposition of impermeability to Cr 3+ .Although proanthocyanidin mutants displayed reduced germination in the presence of chromium, their embryo viability was only partially affected by higher levels of Cr 3+ .Also, it was observed that decreases in germination (%) and embryo viability was not always associated with increased seed coat permeability to tetrazolium salt.Overall, these results reveal the risks associated with Cr 3+ toxicity on the existence of plants with reduced seed coat suberin content in environments contaminated with high levels of chromium.The findings presented in this thesis helps to clarify how suberin content, composition, and lamellae structure relate to tolerance against drought, salinity, and chromium (Cr 3+ ) toxicity.Further, these findings shed light on future directions in manipulating suberin genes for the development of stress-tolerant high-value crops.
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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) | 0.002 | 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 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".