. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. THE CHLOEOPLASTS 141 t& Fig. 71.—Starch grains from the palisade cells of a Euphorbia leaf, magnified about 1800 diameters. The first visible food made by the chloroplasts is starch in the form of very minute grains (Fig. 71). There is reason to believe that sugar is formed before the starch appears, and presumably in the chloroplasts also, but it is soluble in the cell- sap and probably does not long remain where it is first formed, but passes by diffusion fro
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. THE CHLOEOPLASTS 141 t& Fig. 71.—Starch grains from the palisade cells of a Euphorbia leaf, magnified about 1800 diameters. The first visible food made by the chloroplasts is starch in the form of very minute grains (Fig. 71). There is reason to believe that sugar is formed before the starch appears, and presumably in the chloroplasts also, but it is soluble in the cell- sap and probably does not long remain where it is first formed, but passes by diffusion from the chloro- plasts into the cell-sap that fills the cell cavity, and thence into the tissues de- voted to food-conduction, as told in the next chapter. The minute size of the chloroplasts affords them large surface in proportion to their volume, and this gives a great advantage in the absorption of raw materials and energy, and in the elimination of the finished product. The chloroplasts are always em- bedded in the cytoplasm close against the cell-wall, and this peripheral posi- tion is apparently an advantage to every phase of their work; for, as Fig. 72 will show, on one side water is presented to the chloroplasts from the cell-sap, and on another carbon dioxide from the intercellular spaces, and the vacuole affords an unob- structed way for the removal of the manufactured product. Also by this arrangement the light entering the leaf from all parts of the sky has a clearer path to every chloroplast throughout the leaf than would otherwise be the case (Fig. 73).. Fig. 72.—Diagram to show the intake of carbon dioxide by the palisade cells from the inter- cellular spaces, the absorption by the chloroplasts of water from the cell-sap, and the passage of food from the chloroplasts into the cell-sap. The palisade cells are shown in cross section, as they would be if the leaf were cut parallel with the surface, namely, Please note that these images are extracte
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplantanatomy, bookyea
