Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 126-136).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1928. / Author's name is Pieh ; appears as Piehl on t.p. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, 1922. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." Contributions from the Hull botanical laboratory 293 and 295. "Reprinted from the Botanical gazette, vol. LXXIII, nos. 4 and 6, April and June, 1922." "Literature cited": p. 323-324, 446. Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, 1912. / Plate 13-14 each preceded by leaf with descriptive letter press. [Reprinted from Publication 193 of the Carnegie institution of Washington]. Also available on the Internet. Also issued online.

No description available.

Aging of ray parenchyma cells from the young sap-wood to recently formed heartwood was studied in single stems of Pinus banksiana Lamb., Picea mariana (Mill.) B.S.P., Abies balsamea (L.) Mill, and Populus tremuloides Michx. Season, radial location of cell within sapwood, and cell location vertically within a ray at a given radius were considered as factors which might influence the aging process. A 12 mm increment core was extracted at breast height, from the north aspect of a tree of each species in May and July for moisture content determination. Another set of cores from the south aspect of the same trees was collected in May, June, July, August, October, and November or December. These cores were used to investigate the physiological and cytological properties of living sapwood ray parenchyma cells. Qualitative and quantitative observations were made of the status of ray cells both with light and transmission electron microscopy in order to draw inferences concerning the sapwood/heartwood transformation from the aging of sapwood ray parenchyma cells. The sapwood moisture content of the three conifers studied was higher than that of heartwood, whereas in Populus tremuloides it was lower than that of heartwood. The sapwood moisture content in May was consistently greater than in July. Vitality of the sapwood ray parenchyma cells expressed by a new nuclear elongation index decreased from the outer sapwood towards the heartwood. The survival rate of the cells decreased curvilinearly from the middle sapwood towards the heartwood. At a given sapwood increment, a greater percentage of dead ray parenchyma cells was found among the marginal cells than among the central cells of a ray. No statistically significant difference was found between the vitality of the marginal and central cells, nor between any two contiguous sampling periods with exceptions in Pinus banksiana and Picea mariana between two contiguous sampling periods from July to December. No typical pattern for the distribution of lipid content was found. The pattern of starch distribution displayed significant species, radial, vertical and seasonal variation and showed two general patterns across the sapwood. Pattern A described a decreasing trend from the outer sapwood towards the inner sapwood. Pattern B was characterized by a relatively low starch content both in the outer as well as the inner sapwood. The starch content in Populus tremuloides and the lipid content in Pinus banksiana and Picea mariana displayed no statistically significant difference between marginal and central ray cells. The majority of ray parenchyma cells showed a statistically significant difference between two contiguous sampling periods in starch and lipid contents. There was no inverse relationship between the starch and lipid content over the growing season studied. Young ray parenchyma cells were rich in chromatin and cytoplasm which contained numerous cell organelles. These cells were characterized by amyloplasts which possessed one or more elongated starch granules with thylakoids and osmiophilic globuli, numerous small lipid droplets and mostly rod-like mitochondria. In contrast, aged ray parenchyma cells featured an aggregated, dense nucleus and cytoplasm which contained few cell organelles. These aged cells possessed enlarged swollen starch granules, large lipid droplets or lumps with two staining densities, round shaped mitochondria with inconspicuous cristae and a rough/broken plasmalemma. Some heartwood substances originated from the lipid lumps which appeared frequently in dying ray cells. Based on microscopic observations and measurements of the loss of vitality of ray parenchyma cells, a declining survival rate, the disintegration of cell organelles and the origin of heartwood substances from lipid lumps, it can be concluded that heartwood formation is largely associated with the death of sapwood ray parenchyma cells. The death of these cells is due to the passage of time. / Forestry, Faculty of / Graduate

The time dependent molecular motions of wood components at straining parallel to fibre direction were observed by infrared polarization technique. A two-stage molecular motion involving three wood components, cellulose, hemicellulose and lignin is suggested as the course of wood molecular relaxation. The first stage begins at equilibrium, when the specimen is not stressed, and extends immediately to a minimum dichroic ratio (formula omitted) of carbo-hydrate components represented by 1160 cm⁻¹ and 1730 cm⁻¹ bands, and the maximum dichroism of lignin (1500 cm⁻¹). The second stage starts at the end of the first stage and extends to equilibrium recovery. Regardless of the form of external excitation (creep or stress relaxation), and the time of excitation (ramp- or step-loading), the basic pattern of the two-stage molecular motion was followed, while damping of the molecules accompanied the whole rheological process. Thus, the wood macromolecular structure maintains an "internal state" of equilibrium on receiving external excitation. This equilibrium state is achieved by moving the carbohydrate and lignin components in opposite directions. The described pattern of molecular motion for a component in wood is a compensatory result from the interference of other components. Removing one or more components from wood changes the motion patterns of the remaining components. The conformation of cellulose in the specimen without the presence of lignin and hemicellulose is comparable to that of other synthetic linear polymers. Energy transfer system of wood was postulated as being due to the directional movement of molecular components which results in association and high steric interference between carbohydrates and lignin, similar to cross-linked chains of lignin and carbohydrates. This energy transfer system of wood is further facilitated by the existence of a systematic structure of wood microfibrils which permits a zone of gradual transition from high crystallinity to a diffuse state. The lignin network of the system may do more than transfer energy, it may act also as an "energy sink" and thereby function to maintain the memory of the excitation. / Forestry, Faculty of / Graduate

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. / Science, Faculty of / Botany, Department of / Graduate

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No description available.