| 释义 |
massula Bot.|ˈmæsjʊlə|
[mod.L., dim. of L. massa: see mass n.2]
(a) In heterosporous ferns of the genera Azolla and Salvinia, the tissue surrounding the maturing microspores; (b) in certain orchids, a cluster of pollen grains developed from a single cell.
1856J. S. Henslow Dict. Bot. Terms (ed. 2) 105 Massula (a little lump). One of the smaller fragments which..compose the pollen mass in Orchidaceæ. 1882S. H. Vines tr. F. G. J. von Sachs's Text-bk. Bot. ii. 454 In the microsporangia [of Azolla] the mucilage looks like a large-celled tissue, and forms from two to eight separate clumps (Massulæ), each of which encloses a number of microspores. In some species..these massulæ have their surfaces covered with hair-like appendages. 1894S. H. Vines Students' Text-bk. Bot. I. iii. 410 In Azolla the microspores are likewise embedded in this substance, but in more than one group or massula according to the species. 1895― Ibid. II. iii. 564 The pollinium may consist..of larger groups of cells, termed massulæ (e.g. Orchis). 1938G. M. Smith Cryptogamic Bot. II. ix. 358 The functional macrospore lies in the large massula at the base of a sporangium. Ibid. 360 A microspore remains embedded within a massula during the entire course of its development into a gametophyte. 1959Wirth & Withner in C. L. Withner Orchids v. 157 In some genera, such as Peristylus, there is a variation on the normal mode of development. All the cells resulting from the divisions of an archesporial cell remain attached to each other, eventually forming a small cluster of tetrads known as a massula. 1965Bell & Coombe tr. Strasburger's Textbk. Bot. 582 Azolla is of interest for the arrangements which ensure fertilization. After liberation from the microsporangium the sixty-four microspores are aggregated into 5–8 roundish floating balls (massulae) formed of the frothy periplasmodium. Arising from the surface of each massula are a number of stalked, barbed hooks. |