Pecan rosette : its histology, cytology, and relation to other chlorotic diseases . Vertical Sections of Healthy and Diseased Pecan Leaflets,Frotscher Variety. Collected on August ; and 26, 1919, at Thomasville, Ga. All figures at the same 540. A.—Healthy pecan leaflet collected at sundown, killed in Carnoys fluid, and stainedwith iodin to show the presence of starch in the palisade and spongy cells. B.—Healthypecan leaflet collected in the morning, killed in Carnoys fluid, and stained with iodin to showthe absence of starch. C and D.—Pecan leaflets aborted with rosette, c
Pecan rosette : its histology, cytology, and relation to other chlorotic diseases . Vertical Sections of Healthy and Diseased Pecan Leaflets,Frotscher Variety. Collected on August ; and 26, 1919, at Thomasville, Ga. All figures at the same 540. A.—Healthy pecan leaflet collected at sundown, killed in Carnoys fluid, and stainedwith iodin to show the presence of starch in the palisade and spongy cells. B.—Healthypecan leaflet collected in the morning, killed in Carnoys fluid, and stained with iodin to showthe absence of starch. C and D.—Pecan leaflets aborted with rosette, collected and treatedin the same way, respectively, as in the preceding two normal leaflets. Chloroplasts in bothnight (C) and morning (D) specimens were gorged with starch, and apparently no trans-location had taken place during the night. Note also the enlargement of the cells in the dis-eased material. Photomicrographs by the writer. Bui. 1038, U. S. Dept. of Agriculture Plate XI. Fresh Living Cells of Pecan Leaves. Camera-lucida drawings of freehand vertical sections, mounted in water. All at the same mag-nification (X about 1,200) and oriented the same as in the leaf. A.—Healthy palisade cell,showing well-defined nucleus and plump livid-green chloroplasts. B.—A disorganization stageof a palisade cell in a leaf affected with rosette; chloroplasts disintegrated and nuclear outlinevague. C—Healthy cell of the spongy parenchyma. D.—Slightly diseased cell of the spongyparenchyma in which the chloroplasts have lost a part of their green color. E.—Spongy paren-chyma cell at the margin of a yellow area. The protoplasmic structures on the side toward thespot (right) are disorganized and the nucleus is fragmenting. Chloroplasts next to the greenperiphery of the spot (.left) are still green and unfragmented, though a part of them are smallerthan normal. F and G.—Spongy ceUs at further stages in disorganization. H.—Spongy cellshowing entire disorganization
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherwashi, bookyear1922
