The Journal of the Department of Agriculture, Victoria . 9. TRANSVERSE SECTION OF A YOUNG WHEATROOT SHOWING ROOT HAIRS (/•//.), VASCULARBUNDLE (), EPIDERMIS ((), AND GROUNDTISSUE. lo March, 1912.] WJieat and its Cultivation. starch, is insoluble in water, is acted on by a ferment present in the grain,and is broken down into diffusible proteids called peptones. Jhese solublepeptones, as well as other nitrogenous compounds of lesser importance(amides and amido-acids) diffuse from cell to cell and nourish the growingtissues of the young embryo. It is not long before the reserves of foodin the
The Journal of the Department of Agriculture, Victoria . 9. TRANSVERSE SECTION OF A YOUNG WHEATROOT SHOWING ROOT HAIRS (/•//.), VASCULARBUNDLE (), EPIDERMIS ((), AND GROUNDTISSUE. lo March, 1912.] WJieat and its Cultivation. starch, is insoluble in water, is acted on by a ferment present in the grain,and is broken down into diffusible proteids called peptones. Jhese solublepeptones, as well as other nitrogenous compounds of lesser importance(amides and amido-acids) diffuse from cell to cell and nourish the growingtissues of the young embryo. It is not long before the reserves of foodin the .seed are exhausted, and henceforth the young plant must lead anindependent existence. At this stage an examination of the root systemwill reveal several interesting Along the greater portions of the roots, minute delicate fibrils will beobserved. These are the tender root hairs which push their way throughthe minute interstices between the soil particles and apply themselves. ro. TRANSVERSE SECTION OF WHEAT ROOT (x 270). closely to the uneven edges of the soil grains. Microscopical examinationproves them to be long tubular appendages—mere delicate prolongations ofthe epidermis. The epidermis forms the external Jayer of the root. may be seen in Fig. lo, it is composed of cells packed togetherwith no interstitial spaces or openings of any kind. In this respect,as will be shown later, it differs markedly from the epidermis of the this absence of openings it will be clearly apparent that the plant,so far as the root system is concerned, is quite incapable of appropriatingfood of a .solid character from the soil. Whatever nutrients are obtainedfrom the soil, therefore, must be liquid or gaseous in character. Now theparticles that compose a normal soil in good condition are very irregular i84 Journal of Agriculture, Victoria. [lo March, 1912. in shape, and are invested with a film of water. This film of moisturesurrounding each soil p
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectagricul, bookyear1902
