Identifier: pecanrosetteitsh1038rand (find matches)
Title: Pecan rosette : its histology, cytology, and relation to other chlorotic diseases
Year: 1922 (1920s)
Authors: Rand, Frederick Vernon, 1883-1961
Subjects: Pecan rosette Pecan
Publisher: Washington, D.C. : U.S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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ber of cell divisions and partly to the shortened verticalaxis of the palisade cells. The elongated shape of the leaves, how-ever, is not due to variations in cell shape but rather to a decreasein the number of cell divisions in which the central spindles areperpendicular to the midrib. This would tend to keep the cells closerto the main water supply of the leaf. Amelung (9) working with plants and Conklin (25) workingwith animals have shown that normal tissue cells of correspondingorgans or parts of organs within a species or variety are in generalof the same size and that the size of organs is primarily due todifferences in the number rather than in the size of cells. Mrs.Tenopyr (77). as a result of investigations in several species ofplants, found that difference in the shape of leaves of the sameplant or related species is not correlated with difference in the shapeof their cells. Linear leaves are not composed of longer, narrower Bui. 1038, U. S. Dept. of Agriculture. PLATE VI 0
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Vertical Sections of Pecan Leaves Killed with Carnovs Fluid. Flemings triple stain used. A, C, and E toH, Van Deman variety. Collected in July, 1913, atBelleview, Fla. A.—Section of healthy leaflet at the margin, showing well-defined palisadeand spongy parenchyma and large intercellular spaces. B.—Section of a yellow, thin area ina large rosetted leaflet, showing a differentiated palisade, but close packing of the cells. C.—Section through the yellow area of a much-aborted leaflet where the tissues have partially col-lapsed. There is no well-defined palisade tissue. D.—Section of a much-aborted leaflet at themargin, showing the close packing of the cells. E and F— Sections through the yellow, thinportions of a badly mottled but nearly full-sized leaflet, showing the lack of differentiationinto palisade and spongy parenchyma, almost complete obliteration of intercellular spaces, anddifference in the leaf diameters in the center (F) and toward the margin (E) of a yellow spot.G

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