Journal of agricultural research . the method described by Crabill andReed (4). Within a week a clear halo around the edge of the bacterialcolony is formed on this substratum, thus making a striking oculardemonstration of dissolution of starch by the canker organism. Ifdiastase, secreted by this organism, is readily diffusible through the cellwalls, and it is reasonable to suppose that it is, it can convert the rela-tively insoluble starch into more soluble carbohydrates and thus increasethe osmotic pressure of the cell sap. It is not impossible that these several causes of increased osmoticpr
Journal of agricultural research . the method described by Crabill andReed (4). Within a week a clear halo around the edge of the bacterialcolony is formed on this substratum, thus making a striking oculardemonstration of dissolution of starch by the canker organism. Ifdiastase, secreted by this organism, is readily diffusible through the cellwalls, and it is reasonable to suppose that it is, it can convert the rela-tively insoluble starch into more soluble carbohydrates and thus increasethe osmotic pressure of the cell sap. It is not impossible that these several causes of increased osmoticpressure operating conjointly or separately may so profoundly modify theimbibitory properties of certain col-loidal substances within the cells thattheir affinity for water is in conse-quence greatly increased. No attempt has been made to de-termine the isotonic coefficient of thecell contents of the enlarged cells, butfor the reasons just mentioned it isbelieved to be greater than that ofnormal cells. DISINTEGRATION OF THE TISSUES. Fig. 7.—Cross section in outline of a spongy cankeron the rind of a fruit of Citrus decumana, show-ing ruptured epidermis and hypertrophy of therind tissues, the cells of which are loosely at-tached. An attempt has been made to gaincertain information relative to theorganisms involved in the disintegra-tion of cankerous tissues, together with the nature of their activity on thistissue. It was previously pointed out that a species of Phoma is com-monly associated with Citrus canker. Two other species of fungi belong-ing to the genera Gloeosporium and Fusarium are also sometimespresent. Since certain bacteria and fungi are known to possess the powerof hydrolyzing cellulose (13, 15), of which complex substance cell wallsare largely constituted, an effort has been made to study the action ofthe organisms associated with canker upon pure cellulose. For thispurpose cellulose agar was prepared according to the following reagent was first
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagricul, bookyear1913
