| 单词 | companion cell |
| 释义 | > as lemmascompanion cell companion cell n. [in later use (in quot. 1880 and later) after German Geleitzelle (1872 or earlier)] Botany (in the phloem of flowering plants) a specialized elongated cell, one or more of which is typically connected to, and regulates the movement of substances into and out of, each sieve cell; (in early use also) †a cell that has recently divided from another (obsolete). ΘΚΠ the world > plants > part of plant > cell or aggregate tissue > [noun] > cell > types of > other types bast cell1842 basal cell1846 pollen cell1857 companion cell1859 segment1862 pollen mother cell?1870 sextant1875 transfusion cell1875 idioblast1882 trichoblast1882 symplast1894 megasporocyte1924 oat cell1940 heterokaryon1945 1859 Proc. Dublin Univ. Zool. & Bot. Assoc. 1 127 A flattened or depressed circular portion..possibly representing the somewhat flattened surface of contact with the companion cell. 1880 Nature 28 Oct. 602/2 Two unequal cells: the larger forms one member of the sieve-tube; the other, which is smaller and shorter, develops into the companion-cell (Geleitzelle). 1902 Encycl. Brit. XXV. 417/1 The proteid cells of the phloem are here always sister-cells of the leptoids and are known as companion-cells. 2007 S. Lalonde in K. Roberts Handbk. Plant Sci. II. 191/2 In gymnosperms, the functional equivalents to angiosperm companion cells are Strassburger cells. < as lemmas |
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