Leaf thickness of Salix spp. (Salicaceae) from the Athabasca sand dunes of northern Saskatchewan, Canada

2004 ◽  
Vol 82 (11) ◽  
pp. 1682-1686 ◽  
Author(s):  
R L Cooper ◽  
J V Ware ◽  
D D Cass

Leaf thicknesses of Salix taxa (Salix brachycarpa Nutt. var. psammophila Raup, Salix planifolia Pursh subsp. tyrrellii (Raup) Argus, Salix silicicola Raup, and Salix turnorii Raup) from the Athabasca sand dunes in northern Saskatchewan, Canada, were evaluated and compared with those of their respective widespread progenitors (S. brachycarpa Nutt. var. brachycarpa, S. planifolia Pursh subsp. planifolia, Salix alaxensis (Anders.), and Salix eriocephala Michx. var. famelica (C. R. Ball) Dorn). Leaf thickness was measured using standard light microscopy, and results were compared with the occurrence of amphistomaty in these Salix species. Leaf thickness values varied among the species and differed significantly within each derivative–progenitor Salix pair. The two amphistomatic taxa from Yakow Lake dunes, S. turnorii and S. planifolia subsp. tyrrellii, had significantly thicker leaves (337.65 ± 5.99 µm and 226.00 ± 5.22 µm, respectively) than their widespread progenitors, as well as the thickest leaves overall. The data comparison indicates a relationship between amphistomaty and leaf thickness among the Salix taxa, as thicker leaves tend to be amphistomatic.Key words: amphistomaty, Athabasca sand dunes, leaf thickness, Salix, willow.

2003 ◽  
Vol 81 (7) ◽  
pp. 749-754 ◽  
Author(s):  
Ranessa L Cooper ◽  
David D Cass

The Athabasca sand dunes are located on the south shore of Lake Athabasca in northern Alberta and Saskatchewan, Canada. Four willow shrubs (Salix; Salicaceae) occur on the open sands, two of which are endemic to the Athabasca sand dunes. Light and scanning electron microscopy were used to quantify stomatal frequency, stomatal index, trichome density, and cuticle thickness, for the Athabasca sand dune willows and their associated putative progenitors. The Athabasca sand dune taxa (Salix brachycarpa var. psammophila, Salix planifolia subsp. tyrrellii, Salix silicicola, and Salix turnorii) occur primarily on the inner dunes, and each has certain leaf epidermal features that appear to be adaptive to the exposed nature of the open sand habitat and the high light intensity. Salix brachycarpa var. psammophila and S. silicicola have tomentose leaves, with trichome densities that are significantly greater than those of their respective widespread progenitors. Salix planifolia subsp. tyrrellii and S. turnorii have amphistomatic leaves and substantially thicker cuticles than their associated progenitors. This investigation is the first to compare adaptive leaf epidermis features within the derivative–progenitor Salix pairs. Considerations for the significance of amphistomaty in the Athabasca sand dune Salix taxa are discussed.Key words: Athabasca sand dunes, cuticle, Salix, stomata, trichomes, willow.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.


Author(s):  
Bruce Mackay

The broadest application of transmission electron microscopy (EM) in diagnostic medicine is the identification of tumors that cannot be classified by routine light microscopy. EM is useful in the evaluation of approximately 10% of human neoplasms, but the extent of its contribution varies considerably. It may provide a specific diagnosis that can not be reached by other means, but in contrast, the information obtained from ultrastructural study of some 10% of tumors does not significantly add to that available from light microscopy. Most cases fall somewhere between these two extremes: EM may correct a light microscopic diagnosis, or serve to narrow a differential diagnosis by excluding some of the possibilities considered by light microscopy. It is particularly important to correlate the EM findings with data from light microscopy, clinical examination, and other diagnostic procedures.


Author(s):  
Gladys Harrison

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.


Author(s):  
Joseph E. Mazurkiewicz

Immunocytochemistry is a powerful investigative approach in which one of the most exacting examples of specificity, that of the reaction of an antibody with its antigen, isused to localize tissue and cell specific molecules in situ. Following the introduction of fluorescent labeled antibodies in T950, a large number of molecules of biological interest had been studied with light microscopy, especially antigens involved in the pathogenesis of some diseases. However, with advances in electron microscopy, newer methods were needed which could reveal these reactions at the ultrastructural level. An electron dense label that could be coupled to an antibody without the loss of immunologic activity was desired.


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