| 释义 |
microspore|ˈmaɪkrəʊspɔə(r)|
[f. micro- + spore.]
1. Bot. and Path. A parasitic fungus which has small spores, characteristic of ringworm. = microsporon.
1856Mayne Expos. Lex., Microsporum..term for the cryptogamious plant in Porrigo decalvans,..a microspore. 1899Allbutt's Syst. Med. VIII. 855 The microspores and trichophytes all belong to the same family.
2. Bot. The smaller of the two kinds of spores in heterosporous cryptogams; also, the homologous structure in seed plants (i.e. the immature pollen grain).
1858Carpenter Veg. Phys. §734 One containing a mass of fine powdery granules (microspores); the other including only three or four roundish fleshy bodies (megaspores). 1875Bennett & Dyer Sachs' Bot. 336 The Marsiliaceæ and Selaginelleæ produce their antherozoids within the microspore itself. 1877Le Conte Elem. Geol. (1879) 355 [There are in Lepidodendrids] two kinds of spores—microspores and macrospores—corresponding to stamens and pistils. 1964E. J. H. Corner Life of Plants x. 177 The male spores [in Selaginella, etc.], called microspores because of their small size, are produced in large numbers in microsporangia. 1965K. Esau Plant Anat. (ed. 2) xviii. 540 A microspore develops into the male gametophyte, the pollen grain.
3. Zool. A spore-like form in Protozoa. Also used for microgamete.
1882Kent Man. Infusoria II. 870 Microspores. The spore-like elements, of exceedingly minute size but very numerous, produced through the encystment and subsequent subdivision of many monads. 1905McCabe tr. Haeckel's Evol. Man I. 140 The smaller microspores have the same shape as the larger macrospores.
Hence microˈsporic a. Bot., of or pertaining to a microspore; ˈmicroˌsporous a. Bot., having small seeds or grains; resembling or derived from a microspore; ˌmicrosporoˈgenesis, the development of microspores; ˌmicrosporogeˈnetic a.
1856Mayne Expos. Lex., Microsporous. 1890Cent. Dict., Microsporous. 1897Webster, Microsporic. 1946Nature 12 Oct. 520/1 In the microsporogenesis of buckwheat autotetraploids during the first metaphase of meiosis only very rarely were exclusively quadrivalents observed. 1961Developmental Biol. III. 241 Microsporogenesis in the higher plants offers an opportunity for analyzing various stages of differentiation within the essentially closed system afforded by the microsporocyte. 1973Nature 6 July 35/2 The cold treatment slowed down the microsporogenesis considerably, enabling the microsporogenetic stages to be clearly recognized.
Add: microˈsporocyte n. Bot., a mother cell that divides to form four microspores.
1916B. D. Jackson Gloss. Bot. Terms (ed. 3) 234/2 Microsporocyte, the mother-cell of a microspore or pollen-grain. 1936J. B. Hill et al. Botany xviii. 583 The reduction division in the microsporocytes is followed by an equation division in each of the two nuclei. 1977K. Esau Anat. Seed Plants (ed. 2) xxi. 405/2 The continuity of the microsporocytes is thought to account for the closely synchronous meiosis within a microsporangium frequently observed in angiosperms. |