| 释义 |
prothallial, a. Bot.|prəʊˈθælɪəl|
[f. next + -al1.]
Pertaining to or of the nature of a prothallium; spec. applied to a small cell formed at an early stage in the development of the male gametophyte of certain gymnosperms, or a similar structure in certain pteridophytes. So proˈthallic, proˈthalline adjs.
1876J. H. Balfour in Encycl. Brit. IV. 160/1 In Ferns the alternation consists of two dissimilar generations,—a sexual or prothallial generation, and an asexual generation. 1882J. M. Crombie ibid. XIV. 555/2 Their fecundating influence is rather exercised on the prothalline elements of the growing thallus. 1890Cent. Dict., Prothallic. 1892Ann. Bot. VI. 214 Judging from the obvious continuity of the dividing wall with the lateral walls of the prothallial chambers..there can hardly exist a doubt that the two cavities result from a primary transverse division of the cell. 1910Coulter & Chamberlain Morphol. Gymnosperms vi. 277 The appearance of two evanescent vegetative (prothallial) cells is a feature only of the Abietineae. 1929Robbins & Rickett Botany xxii. 326 Two are very small cells (prothallial cells) which die and disintegrate almost as soon as formed. 1965Bell & Coombe tr. Strasburger's Textbk. Bot. 593 In the originally unicellular microspore (pollen grain) [of Pinus] one or two (or sometimes more) small cells are formed at a particular spot just inside the wall; these prothallial cells often degenerate after a time. 1969F. E. Round Introd. Lower Plants xi. 132 The microspore divides within the spore wall to form a single ‘prothallial’ cell and an antheridial initial cell. 1973A. Cronquist Basic Bot. xvi. 262 The prothallial cell [of Selaginella] is considered to be an evolutionary vestige of the body of the gametophyte. |