Response of barley, field pea, canola and tree seedlings to ethylene exposure : Alberta's ethylene/crop research project : report III /
Bibliographic record
Abstract
The Alberta Ethylene Crop Research Project was a multi-stakeholder initiative to investigate the response of selected cultivars of agricultural crops of interest to Alberta producers to ethylene exposure.The goals of the project were to:• Provide scientific information to Alberta Environment for further development of ambient air quality guidelines for ethylene, and to ,• Provide the petrochemical industry and communities adjacent to petrochemical facilities with scientific information for site-specific risk assessment. ApproachThis research project was conducted in three phases.The results of the first two phases, development of a growth chamber system for ethylene exposures and the evaluation of crop and cultivar sensitivity to ethylene, have been presented in earlier reports.The results presented in this report describe the responses of barley cv.Harrington, canola cv.Quantimi and field pea cv.Carrera to a range of ethylene exposure regimes and concentrations.An examination of the effects of short-term ethylene exposure on white spruce and lodgepole pine seedlings was also conducted.On the basis of the results of these experiments, an examination of mathematical evaluations of responses to ethylene exposures was conducted to assist in the interpretation and application of the results in guideline development and risk assessment.For the purpose of this study, effects of ethylene on yield were deemed more important than effects on vegetative characteristics.This is the third and final phase of the project. Summary of Conclusions1.No significant effects of short-term exposure to ethylene, up to 1200 ppb for 12 hours, were observed on vegetative and reproductive characteristics in barley, field pea and canola.Similarly, no effects of short-term exposures to ethylene, up to 1200 ppb for 12 hours, were observed on seed germination, seedling vigour, growth in the rapid growth phase, and seedling marketability in lodgepole pine and white spruce.2. Several vegetative and reproductive symptoms of ethylene exposure were observed in the three crop species studied in long-term exposure.Ethylene symptoms appeared earliest in field pea and symptoms were most noticeable.Photographs of these symptoms are contained within this report.3. Barley cv.Harrington is more sensitive to ethylene exposure than field pea cv.Carrera and canola cv.Quantum.For this reason, the majority of the experiments were conducted using barley.4. The response of plants to long-term ethylene exposure depends on both concentration and length of exposure.Minimum ethylene concentrations and length of exposure that are required to cause an effect are species-specific.Barley yields were reduced significantly when plants were exposed to 50 ppb ethylene for 3 days, while no significant decrease in seed yield of field pea was observed when plants were exposed to 50 ppb ethylene for up to 26 days.5. The ability to recover from the effects of long-term ethylene exposure is speciesspecific.Significant reductions in yield of field pea were observed in plants exposed to ethylene at concentrations above 100 ppb for 16 days, however, given sufficient time following treatment, complete recovery of yield in field pea was observed.Barley and canola did not appear to have the recovery abilities of field pea.6.The sensitivity of barley varies with the time of day of ethylene exposure.Barley was most sensitive to ethylene during the middle of the day [between 10:00 a.m. and 4:00 p.m.]. 7. Exposure of barley plants to an ethylene pattern derived from ambient air monitoring data from the worst month of exposure seen at a petrochemical facility in Alberta over a three year period had no significant effect on yield.Exposure was at the most sensitive stages of barley growth and reproductive development.\ , iv 8. Intermittent exposure experiments indicated that exposure of barley to five intermittent exposures of 250 ppb ethylene caused a reduction in yield.Significant experimental difficulties were encountered in this part of the work.Intervals as long as 5 days between exposures were not sufficient to allow for complete recovery.9.The application of mathematical expressions of dose to the data indicate that the interim 6-hour Alberta Air Quality Ethylene Guideline (120 |j.g m ^ or 104 ppb) appears to be conservatively protective of barley, canola and field pea from yield reductions due to short-term ethylene exposure.The interim 30-day Alberta Air Quality Ethylene Guideline (50 \ig m-3 or 44 ppb) appears to be protective of yield effects in canola and field pea; however, yield effects may occur in barley at levels below the 30-day interim Alberta Air Quality Ethylene guideline (50 \xg m-^ or 44 ppb).
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".