. Botany for high schools and colleges. Botany. CELL FORMATION BY DIVISION, 39 ia) The foregoing must suffice as examples of Fission. It occurs throughout the vegetable kingdom and may be regarded as the great means by which cells are multiplied. (&) The cambium zone of Dicotyledons may be examined very profit- ably by the student. If a thin cross-section of a stem be soaked for a short time in a carmine solution, the protoplasm of the cambium zone will be colored, and the newly formed partitions made thus more distinct. (c) The ends of young roots are valuable for study ; longitudinal sec
. Botany for high schools and colleges. Botany. CELL FORMATION BY DIVISION, 39 ia) The foregoing must suffice as examples of Fission. It occurs throughout the vegetable kingdom and may be regarded as the great means by which cells are multiplied. (&) The cambium zone of Dicotyledons may be examined very profit- ably by the student. If a thin cross-section of a stem be soaked for a short time in a carmine solution, the protoplasm of the cambium zone will be colored, and the newly formed partitions made thus more distinct. (c) The ends of young roots are valuable for study ; longitudinal sec- tions of these should be made, and treated as in the previous case. {d) Another interesting study of a special kind of fission may be taken up in an examination of the development of stomata. (See p. 99.) (e) That slight variation of fission, which has sometimes been called budding, may be very easily studied in the Yeast Plant {Saccliai'omyces cerevisice).* The conidia, stylospores, and basidiospores of many fungi, which are more difficult to study, are very instructive examples of this va- riety of fission. Conidia may be studied in Cystopus; stylospores in the Red Rust of the grasses (the so- called uredo-stage of Puccinia gram- inis) ; and basidiospores in young toadstools (Agaricus). 1^1 Tba VoQQf Plcmf /'<^/^,/. Fig. 29.—TheYeasfPlant, Sacckaro- ox. xiit; _Lt;ci&u i iciuu ykjuo- myces cerevzsice. a, rounded cells charomyces cerevisim) inrmshes i'o':XgTZlZ% f, ^oToft'^ a yery simple example of Inter- J^st S !!^hn f'p?eTo" nal Cell-Formation. Under carrot four cells forming in the inte- rior of the parent cell; d, the four certain conditions tlie cells 2T0W danghter-cells ; a and & x 400, c and d , • ; 1 n X 750,—After Reets. to a larger size than usual; their protoplasmic contents divide into, generally, four parts (two to four, according to Sachs), each of which rounds itself up and secretes a wall of cellulose on its sur- face (Fig. 29, c, d).
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