| 释义 |
proembryo Bot.|prəʊˈɛmbrɪəʊ|
[a. G. (M. J. Schleiden Grundzüge der Wissenschaftlichen Botanik (1843) II. iii. 52), f. pro-2 1 + embryo; so F. proembryon.]
A term which has been applied to various structures of plants: e.g. to the prothallus of the Pteridophyta (Ferns, etc.); but more especially to embryonic structures, such as the protonema of Bryophyta (Mosses, etc.), and the embryos of certain Algae (e.g. Chara, Batrachospermum). In seed plants, the group of cells formed by the early divisions of the zygote after fertilization; also, a young embryo. Also attrib.
1849Lankester tr. Schleiden's Princ. Sci. Bot. 174 (Mosses) The spore-cell expands, emerges from its torn outer coat, and, new cells being developed at the free end, forms for itself a filamentous tissue, composed of linear cylindrical cells ranged end to end (the proembryo). Ibid. 198. 1862 F. Currey tr. Hofmeister's On Germination of Higher Cryptogamia & Fructification of Coniferæ xvi. 441 The breaking up of the pro-embryo of the Coniferæ into a number of independent suspensors is a phenomenon of the most peculiar kind. 1863M. J. Berkeley Brit. Mosses Gloss. 312 Proembryo, the same with cotyledonoids. (Cotylenoid = a term applied to the germinating threads of mosses.) 1875Bennett & Dyer Sachs's Bot. 311 Mosses. The spore produces a conferva⁓like thallus, the Pro-embryo or Protonema. Ibid. 312. 1882 Vines Sachs's Bot. 292 Characeæ. As a consequence of fertilisation the large cell of the carpogonium becomes a resting spore, producing, by its germination, a pro-embryo from which the sexual plant springs as a lateral shoot. 1919F. O. Bower Bot. Living Plant xvii. 274 The very first division of the zygote stamps the polarity of the pro-embryo. 1950D. A. Johansen Plant Embryol. xii. 76 The young pro⁓embryo completely fills the archegonium in Torreya taxifolia. 1964H. J. Dittmer Phylogeny & Form in Plant Kingdom xxiv. 587 Embryonic development in this plant [sc. tansy mustard] begins with a series of transverse divisions of the zygote forming a chain of proembryo cells. 1978Nature 2 Feb. 441/1 Frequently only two seedlings germinate from a single seed and this suggests that only a small proportion of proembryos reach maturity.
Hence proembryˈonic a., of, pertaining to, or having the character of a proembryo.
1875Bennett & Dyer Sachs's Bot. 282 (Characeæ) The Pro-embryonic Branches..have a similar structure to the pro-embryos which proceed from the spores... They have only been observed in Chara fragilis. 1888Henslow Orig. Floral Str. 281 Even after fertilization the embryo cannot grow to maturity, but remains in the arrested proembryonic condition. 1957H. C. Bold Morphol. Plants xxvii. 522 All of the proembryonic cells descended from the zygote may begin to develop into embryos. |