. Bulletin. Agriculture; Agriculture -- Arizona. 34 CAUSE AND NATURE OF CKOWN-GALL or on a seedling in water culture, so that the light has access to it, after a time it changes to light green from the development of chlorophyl in some of its outer cells. Its growth is sur- prisingly rapid. When kept in a water culture for purposes of observation the increase in size can be readily recognized from day to day. In a mouth's time a rapidly developing specimen may grow from a scarcely discernible speck on the side of the root to a body more than a quarter of an inch in diameter. At first the gall
. Bulletin. Agriculture; Agriculture -- Arizona. 34 CAUSE AND NATURE OF CKOWN-GALL or on a seedling in water culture, so that the light has access to it, after a time it changes to light green from the development of chlorophyl in some of its outer cells. Its growth is sur- prisingly rapid. When kept in a water culture for purposes of observation the increase in size can be readily recognized from day to day. In a mouth's time a rapidly developing specimen may grow from a scarcely discernible speck on the side of the root to a body more than a quarter of an inch in diameter. At first the gall has a uniforn outer surface, but after a time it becomes somewhat warty from unequal growth. Under ad- verse conditions the growth may be checked for a time, but if this continues the outer portion begins to assume a reddish brown color, which gradually darkens and extends over and through the entire gall. Decay soon sets in and the whole of the hypertrophied tissue falls away or can be readily broken from the root. Early in its life the surface of the gall loses its white appearance and darkens to a reddish brown, probably from the disorganization of the contents of the outer cells and the action of various species of saprophytic fungi upon them. After any portion of a gall has changed color that portion has lost the power for further growth. Specimens are occasionally observed where a new growth begins as clear transparent globu- lar pustules in hundreds of places on the surface of a large gall (Fig. 11). In such instances the places immediately under the new growths retain their normal whiteness, while the remainder of the surface is discolored to a considerable PIG. 12.—The root and stem of an almond seedling, cut longitudinally so as to show the gall Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble th
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Keywords: ., bookauth, bookcentury1800, bookdecade1890, booksubjectagriculture
