. Botany, with agricultural applications. Botany. CELL MULTIPLICATION 125 the distribution of the chromosomes. At this stage it becomes apparent that each chromosome consists of two pieces or halves, each apparently having spUt longitudinaUy. The halves of each chromosome now separate, pass to opposite ends of the ceU where the new nuclei are formed. Thus each new nucleus gets as many halves, which soon grow to full size chromosomes, as there were chromosomes in the parent cell. As the new nuclei are forming <WI'^'---"A-l 'V ^'^"â ^J^. s? ^ :V,;(j a\Mr,^ â « y h ^iW^"' »%?
. Botany, with agricultural applications. Botany. CELL MULTIPLICATION 125 the distribution of the chromosomes. At this stage it becomes apparent that each chromosome consists of two pieces or halves, each apparently having spUt longitudinaUy. The halves of each chromosome now separate, pass to opposite ends of the ceU where the new nuclei are formed. Thus each new nucleus gets as many halves, which soon grow to full size chromosomes, as there were chromosomes in the parent cell. As the new nuclei are forming <WI'^'---"A-l 'V ^'^"â ^J^. s? ^ :V,;(j a\Mr,^ â « y h ^iW^"' »%? im^~' ' -, -- â â .â â "*'*ip-'-"x.,.\ / Fig. 110. â Cell division, a, cell in resting stage. 6, chromatin formed into a thread, c, the thread of chromatin broken into segments called chromo- somes, d, chromosomes arranged across the cell for division. Notice the threads called spiadle fibers running through the cell and that the nuclear membrane has disappeared, e, chromosomes have spht and the halves are passing to opposite ends of the cell. /, chromosomes have reached the points where they are to form new nuclei, g and h, new nuclei and cross wall be- tween them forming. a cross wall is formed, which divides the cytoplasm, and cell divi- sion is now complete. Instead of one cell there are now two, each of which after growing to full size will divide in the same manner as the parent cell. Except in certain regions where cell multiplication is the spe- cial function, most cells of the plant sooner or later lose their ability to grow and divide as a result of their modifications which adapt them to their special functions. Thus after cells are. 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 the original Martin, John N. (John Nathan), b. 1875. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1920
