. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 2l8 ZOOSPORES cut off by separating walls to form so-called zoosporangia (Fig. ii8, B). Within each the contents round off and the numerous nuclei take up a position outside the chloroplasts. A pair of cilia arise opposite each nucleus, so that a large multi- ciliate oval zoo- spore (Fig. ii8, C) is formed, which escapes into the water by the breaking down of the tip of the sporan- gium. Its move- ments are slow and usually cease after a short time with the withdrawal of the cilia ; a thin wall is formed and
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. 2l8 ZOOSPORES cut off by separating walls to form so-called zoosporangia (Fig. ii8, B). Within each the contents round off and the numerous nuclei take up a position outside the chloroplasts. A pair of cilia arise opposite each nucleus, so that a large multi- ciliate oval zoo- spore (Fig. ii8, C) is formed, which escapes into the water by the breaking down of the tip of the sporan- gium. Its move- ments are slow and usually cease after a short time with the withdrawal of the cilia ; a thin wall is formed and the two ends lengthen into tubes, of which one frequently penetrates the soil or mud and becomes a colour- less attaching organ (Fig. Ii8, E, r.). Zoospores are also encountered in some of the Brown Algre, in Eciocarpiis and Laminaria. In the former they develop in considerable numbers in oval sporangia, each borne laterally on a branch of the filament (Fig. iiq, f), and liberating its contents by rupture of the apex. The pear-shaped zoospores have two. Fig. ii8. Vaucheria. A, Portion of a plant show- ing the branched non-septate thallus and tlic colourless rhizoid-like attaching organ ()-.). B, Zoosporangium. C, Zoospore. T>, Small part of thallus, showing the numerous chloro- plasts (c), and nuclei («â ). E, Germinated zoospore. (C after Oltmanns ; rest original.). 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
