@article{0fb3d4099e1a4cc69a40376a4149656b,
title = "Zooidogamy in the late permian genus Glossopteris",
abstract = "We describe details of anatomically preserved fossil glossopterid ovules from the Late Permian of Queensland, Australia, that contain several pollen tubes at various stages of releasing flagellated sperm. Each sperm is approximately 12.7 μm long and 13.9 μm wide, with a conspicuous spiral structure comprised of a series of dots that resemble the position of basal bodies of flagella aligned along the multilayered structure (MLS). This configuration is similar to the helically arranged flagella in the sperm of cycads, Ginkgo, and many pteridophytes. However, the motile gametes of Glossopteris are considerably smaller than those of Ginkgo and cycads, and more similar in size, number of basal bodies, and number of gyres in their helix to pteridophyte forms. Glossopteris thus shares the intermediate stage of motile male gamete formation and apparently that of haustorial pollen tubes with cycads and Ginkgo.",
keywords = "Glossopteris, Gondwana, Gymnosperm, Seed plant, Sperm, Zooidogamy",
author = "Harufumi Nishida and Kathleen Pigg and Kensuke Kudo and Rigby, {John F.}",
note = "Funding Information: Fig. 2. 8–21 Zooidogamy of Glossopteris homevalensis. Specimen H397018. 8–11 Pollen residues in pollen chamber (at arrows), and a young pollen tube (blue arrowhead in 9). 10 is an enlargement of 9. Note micropyle (white arrowhead), and a residue with reticulate pattern on saccus (blue arrow) in 8. 2 Pollen tube in 11 has one large spermatogenous cell. i Integument, n nucellus. Slides E2lAtop#32, E2lat#3, and E2lAtop#2, respectively. Scale bar 50 mm. 12–15 Serial sections of a pollen chamber of the ovule indicated by arrow in 2, showing five pollen tubes each numbered in red. Arrow in 12 shows possible residues of either or both prothallial and/or sterile cells. Two arrows in 14 indicate released sperm enlarged in 18–20. Slides E2lAtop#34, 33, 31, and 30. Scale bar 100 mm. 16 1 Pollen tube enlarged, showing its haustorial nature. Arrow shows possible branching. Slide E2lAtop#36. Scale bar 50 mm. 17 3 Pollen tube enlarged, showing two young sperm. E2lAtop#31. Scale bar 50 mm. 18–20 Released sperm in 14 enlarged. Scale bars 10 mm. 18 Pair of sperm in the same focal plane. Arrowhead points toward bottom side of each sperm. 19 Pair of sperm each optimized at best focal plane, showing basal body alignment by arrows. 20 Negative color image of 19. Red arrowheads point to some basal bodies of an entire sperm. 21 Suggested reconstruction of an entire sperm with spiral MLS. Dark dots show observed basal body positions. Pale dots show possible positions. Red arrowheads correspond to those in 20 Acknowledgments We thank Mr. Hiromichi Yano for preparing the microscopic slides. The field collection at Homevale was supported by Grants for Overseas Survey from the Ministry of Education, Culture, Sports, Science and Technology No. 04041034 to Prof. Masahiro Kato, University of Tokyo, and No. 08041135 to Dr. Motomi Ito, University of Tokyo, to whom we are deeply grateful. The work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology No. 07640933 to H.N., and NSF grant BSR-9006625 and an Arizona State University Faculty Grant-in-Aid to K.B.P.",
year = "2004",
month = aug,
doi = "10.1007/s10265-004-0164-4",
language = "English (US)",
volume = "117",
pages = "323--328",
journal = "Journal of Plant Research",
issn = "0918-9440",
publisher = "Springer Japan",
number = "4",
}