. Outlines of plant life : with special reference to form and function . Botany. GROWTH. 155 development, the stage of enlargement. This stage is marked by the rapid increase of the cells in size and a much less marked increase in amount of protoplasm present. The in- crease in size, therefore, is mainly due to a great increase in the volume of water, which accumulates in one or more large spaces (C, fig. 117). If the organ in question has an elon-. FiG 117-—Cells from young and mature fruit of snowberry {Spimfihorfcar^us), seen in section A, three young cells, veiy small, walls thin, nuclei r
. Outlines of plant life : with special reference to form and function . Botany. GROWTH. 155 development, the stage of enlargement. This stage is marked by the rapid increase of the cells in size and a much less marked increase in amount of protoplasm present. The in- crease in size, therefore, is mainly due to a great increase in the volume of water, which accumulates in one or more large spaces (C, fig. 117). If the organ in question has an elon-. FiG 117-—Cells from young and mature fruit of snowberry {Spimfihorfcar^us), seen in section A, three young cells, veiy small, walls thin, nuclei relatively large, vacuoles very minute: By two, somewhat older, larger, walls thicker, nuclei smaller, vacuoles several. A and B magnified 300 diam. C, a single cell, mature, magnified 100 one third as much as A and ti; vacuole single, very large. The volume of C is more than 1500 times one of the cells in A. ^, cell-wall;/, protoplasm; k, nucleus-. kkf nucleolus ; s, vacuole.—After Prantl. gated form, such as the stem or the root, growth of the cells takes place chiefly in the direction of its long axis. During this phase the cells may attain a hundred or even a thousand times their former volume. EXERCISE XXXVir. To measure the rate of growth in length. Construct an auxanometer as follows : Take a board 30 cm. square, a common spool, a wheat or oat straw 35 cm. long, and a piece of glass tubing 5 cm. long, which will just allow spool to revolve easily on it. Close one end of the glass tube by holding it in the flame of a Bunsen burner; when hot spread it enough to stop spool from passing over end, by pressing it endwise against a piece of iron. With a fine saw cut a section 5 mm. thick from middle of spool, thus making a wheel. File a groove in edge of this wheel, deep enough to carry a thread. Slip wheel on glass tube and fasten it in board near lower left corner so deep that'. Please note that these images are extracted from scanned page images that may have been
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