Cytological aspects of seasonal changes in the mesophyll chlorenchyma cells of Pinus Contorta dougl. ex loud ssp Latifolia (Engelm, ex wats) in relation to frost hardiness
Bibliographic record
Abstract
The needle chlorenchyma of Pinus contorta Dougl. ex Loud spp. Lat? - folia (Engelm. ex Wats) was fixed on site in the sub-alpine forests of the southern interior plateau of British Columbia, in order to conduct comparative observations by light and electron microscopy on the chloren-chymal cytology in summer and winter. Material fixed in the growing season (summer) demonstrated a chlorenchymal ultrastructure similar to that of other mature higher plant chlorenchymal tissues. Material fixed in mid winter (usually at below freezing tempertures) revealed extensive changes in the structural and positional aspects of most cytoplasmic components. Some of the most dramatic changes in the chlorenchyma cytoplasm in the winter state are as follows: chloroplasts became irregularly shaped and clumped together usually in certain specific areas of the cell; close associations form between the outer membranes of adjacent chloroplasts, these areas may lead to the apparent fusion of some chloroplasts. The cytoplasm became massively vacuolated, particularly in areas removed from the nucleus or the chloroplast clumps. The extent of this vacuolation can be deduced from the use of the adjective "foamy" to describe the extent and degree of these vacuolated cytoplasmic areas. Associated with the cytoplasmic winter vacuoles were highly osmiophilic bodies. A distinct seasonal cycle of cytoplasmic oil reserves was also noted. The reaction of the winter chlorenchymal cytoplasm to extentive manipulation in fixative osmotic potential was remarkably conservative. This observation allows inferences to be made about the permeability characteristics of winter cytoplasmic membranes. In order to verify the observed winter changes, chemical fixation studies were supplemented by observations on material collected, transported, stored, sectioned and observed by light microscopy in the frozen and unthawed, stained or fixed state. This work was conducted with specially designed transport devices and a cryomicrotome and cryomicros-cope. Observations were also conducted in summer and winter on the chlorenchyma of Pinus albicaulis Engelm and Tsuga mertensiana (Bong.) Corr. collected near timberline at the Whistler mountain ski resort ninety miles north of Vancouver. Observations from the cryomicroscopy of Pinus contorta needles indicate that the seasonal changes are not artifacts of chemical fixation procedures. Observations on the needles of the two conifer species collected at Whistler mountain indicate that the detailed seasonal observations on Pinus contorta may also apply to the needle chlorenchyma of other conifer species. A possible spring transitional stage between the winter and summer ultrastructural appearance of Pinus contorta chlorenchyma is discussed. Related experiments were conducted to indicate what effects the needle age of field trees had on winter-summer comparisons, and what effect drought stress and artificial hardening and freezing had on chlorenchymal ultrastructure. The drought and hardening-freezing experiments were conducted on laboratory grown trees in controlled environment chambers. No clear relationship between frost hardiness and drought stress was established. Experiments on the artificial inducement of frost hardiness in seedling trees were not considered successful.
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How this classification was reachedexpand
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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".