Spermatogenisis in the Bryophyta

1911 Annals of Botany  
A LTHOUGH the structure and development of the spermatozoids in ±\. the Bryophyta have been the subject of numerous investigations, comparatively little information is available upon the earlier history of the spermatogenic cells. The majority of investigators have confined themselves to descriptions of the formation of the spermatozoid from the spermatid. Several papers have recently appeared on the spermatogenesis of the Hepaticae, but those dealing with the Musci are very few in number. J.
more » ... few in number. J. and W. Docters van 41, 42) have recently published several on this latter group, and, as pointed out by Strasburger (66), the conclusions arrived at by these observers have emphasized the necessity for further investigation. The first reference to spermatozoids in plants was made by Schmiedel(55) in 1747. In his 'Icones plantarum et analyses partium ', he described the movement of the spermatozoids in Fossombroiiia pusilla. Other scattered observations followed" but the earliest comparative investigations in this subject were made by Hofmeister (28) and described in his' Vergleichende Untersuchungen' in 1850. In several of the Hepaticae he found that the small rectangular cells of the nearly ripe antheridium each gave rise to one spermatozoid. The latter in Pellia epiphylla^ consists of a spirally coiled body with two cilia attached to the thicker end, and, on its escape from the antheridium, it is still enclosed in the wall of the mothercell. This subsequently ruptures, and the spermatid is set free, provided at the thin end with a vesicle. In the Musci the development is similar. In Sphagnum acutifolium the developing antheridia are figured, and the mature spermatozoid is shown, provided with two cilia at the anterior end. In P/iascum cttspidatum spermatozoids are figured still enclosed within the walls of the polygonal mother-cells. The account given by Schimper (54) in 1858 of the spermatozoid of Sphagnum is very similar. With the exception of Pellia, Hofmeister was unable to find cilia in the spermatozoids of the Hepaticae, but in the following year they were described and figured by Thuret (68) in Pellia, 1 By making certain assumptions the number of cells which should be found across the antheridium when cnt in the median longitudinal plane can be calculated. After each successive division the number is increased in the proportion 1 : f/i. If eight cells are found before the penultimate division 8(^7) = 10-08 should be present after its completion and 8 (\Zi)* -ia-7 after the close of the final division. How closely these numbers approximate to those obtained by actual observations may be seen by a comparison of those given above. I am greatly indebted to Mr. Odell, •A.R.C.S., for information as to the factor (v 3 ) involved.
doi:10.1093/oxfordjournals.aob.a089335 fatcat:xotjylyft5b33k7yj3z27leoqu