. Carnegie Institution of Washington publication. B FIG. 64.—Three cells from layer of prothallial cells immediately surrounding upper part of central cell of archegonium of Cycas, showing protoplasmic connections between these cells ; in B the beak of nucleus extends into plasmic bridge.—(After Ikeno.) geneous and diffusely staining bodies. This phenomenon is not confined solely to the cells forming the wall of the archegonium, but it may extend to adjacent cells of the prothallium. This nuclear change takes place only in cells near the upper part of the central cell. Goroschankin has sh
. Carnegie Institution of Washington publication. B FIG. 64.—Three cells from layer of prothallial cells immediately surrounding upper part of central cell of archegonium of Cycas, showing protoplasmic connections between these cells ; in B the beak of nucleus extends into plasmic bridge.—(After Ikeno.) geneous and diffusely staining bodies. This phenomenon is not confined solely to the cells forming the wall of the archegonium, but it may extend to adjacent cells of the prothallium. This nuclear change takes place only in cells near the upper part of the central cell. Goroschankin has shown that in the Cycadacece fine cytoplasmic connections exist between the central cell of the archegonium and the surrounding cells. From Ikeno's figures it seems that the cytoplasmic strands in Cycas are relatively large, and that large granular plasmic masses pass over bodily into the central cell (Fig. 64, A, B). Fre- quently the nucleus itself will send out a beak or protuberance toward the nearest plasmic connection. Arnold! (1900) finds that in several species of Pinus and in Abies the nuclei from the surrounding cells pass into the egg-cell. The prevalence of condensed nuclei in cells surrounding the upper part of the central cell is explained by Ikeno as. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carnegie Institution of Washington. Washington, Carnegie Institution of Washington
Size: 1510px × 1654px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1900, bookyear1904
