Use of Vital Dyes in Conjunction with the Semivitro Technic for the Detection of Pollen Tube Sperm Nuclei

A study of fertilization in Taxus baccata in the electron microscope has revealed novel features. Insemination of the archegonium is facilitated by local perforation of the wall of the young pollen tube. Digestion of the wall begins before the pollen tube pierces the megaspore membrane but is not completed until its tip makes contact with the neck cells of the archegonium. As soon as a pore is formed a single sperm nucleus and some cytoplasm of the male gametophyte enter the archegonium. Which of the paired sperm nuclei move from the pollen tube into the archegonium appears to be a matter of chance. Close apposition of sperm nucleus and egg nucleus is followed by the formation of numerous points of contact between the two. The membranes fuse at these points and pores are rapidly formed. The progressive enlargement of these pores ultimately eliminates any partitions and yields the zygotic nucleus. There is a possibility that, as in some other gymnosperms, the plastids and mitochondria of the zygote come in part from the male gametophyte, but whether from the remains of the spermatogenous cell cytoplasm or from the. pollen tube lumen is not clear.

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Autoradiographs of Pollen Tube Nuclei with Calcium-45

The Journal of Cell Biology ◽

10.1083/jcb.6.3.339 ◽

1959 ◽

Vol 6 (3) ◽

pp. 339-342 ◽

Cited By ~ 20

Author(s):

Dale Steffensen ◽

John A. Bergeron

Keyword(s):

Pollen Tube ◽

Growth And Development ◽

Lilium Longiflorum ◽

Pollen Tubes ◽

Mitotic Division ◽

Generative Nucleus ◽

Tube Nucleus ◽

Easter Lily ◽

Nuclear Component ◽

Sperm Nuclei

Autoradiography with Ca45 has been used to obtain information about the relation between calcium and chromosomes. Labelled pollen from the Easter lily, Lilium longiflorum, was allowed to develop into pollen tubes between 5 and 6 cm. long in the styles of non-radioactive flowers. All of the nuclei, namely the tube nucleus and the two sperm nuclei, retain Ca45 after this period of growth and development. Since the two sperm nuclei have formed during this interval by the mitotic division of the generative nucleus and growth of the tube has occurred under the influence of the tube nucleus, it is inferred that the calcium was bound in a stable nuclear component, the chromosomes.

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Double fertilization in Helianthus

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1973.025 ◽

2015 ◽

Vol 42 (2) ◽

pp. 323-343 ◽

Cited By ~ 3

Author(s):

J. Telżyńska ◽

H. Telżyński

Keyword(s):

Cell Cycle ◽

Pollen Tube ◽

Helianthus Annuus ◽

Morphological Changes ◽

Sperm Nucleus ◽

Double Fertilization ◽

Average Cell ◽

Controlled Pollination ◽

Sperm Nuclei ◽

Ribosome Formation

After controlled pollination of <i>Helianthus annuus</i> L. florets, the whole course of fertilization is described and documented on 24 microphotos. The timing of events is evaluated. The average cell cycle in the proembryo is 2 hours and the nuclear cycle in endosperm - 60 minutes.Plasmoptysis is suggested as the mechanism of pollen tube opening in the synergid. The structure of the thread-like sperm nucleus is interpreted as an end to end union of chromosomes, and the morphological changes of the sperm nuclei are explained as folding and coiling, based on a spiralization mechanism of chromosomes. Cytochemical observations indicating ribosome formation in the course of the nuclear cycles in the endosperm are described. The mechanisms accelerating nuclear cycles in the endosperm are discussed.

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A High Resolution Cytochemical Study of Nuclear ATPase in Human Spermatozoa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116590 ◽

1975 ◽

Vol 33 ◽

pp. 594-595

Author(s):

A. Sosa ◽

L. Calzada

Keyword(s):

High Resolution ◽

Atpase Activity ◽

Nuclear Membrane ◽

Human Sperm ◽

Sperm Nucleus ◽

Human Spermatozoa ◽

Cytochemical Study ◽

Membrane Bound ◽

Sperm Nuclei ◽

Interchromatin Space

The dependence of nuclear metabolism on the function of the nuclear membrane is not well understood. Whether or not the function of the nuclear membrane is partial or totally responsible of the repressed template activity of human sperm nucleus has not at present been elucidated. One of the membrane-bound enzymatic activities which is concerned with the mechanisms whereby substances are thought to cross cell membranes is adenosintriphosphatase (ATPase). This prompted its characterization and distribution by high resolution photogrammetry on isolated human sperm nuclei. Isolated human spermatozoa nuclei were obtained as previously described. ATPase activity was demonstrated by the method of Wachstein and Meisel modified by Marchesi and Palade. ATPase activity was identified as dense and irregularly distributed granules confined to the internal leaflet of the nuclear membrane. Within the nucleus the appearance of the reaction product occurs as homogenous and dense precipitates in the interchromatin space.

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