The reproductive characteristics of core germplasm in a native <i>Metasequoia glyptostroboides </i>population

To obtain further perspective on reproduction and particularly gamete function among so-called primitive mammals presently grouped in the Order Insectivora, we have examined the African hedgehog, Atelerix albiventris, in light of unusual features reported in shrews and moles. Atelerix proves to share many but not all of the characteristics seen in these other insectivores. The penis of Atelerix has a 'snail-like' form, but lacks the surface spines common in insectivores and a number of other mammals. Hedgehog spermatozoa display an eccentric insertion of the tail on the sperm head, and they manifest the barbs on the perforatorium that, in shrews, probably effect the initial binding of the sperm head to the zona pellucida. As a possible correlate, the structural matrix of the hedgehog acrosome comprises only two main components, as judged by immunoblotting, rather than the complex of peptides seen in the matrix of some higher mammals. The Fallopian tube of Atelerix is relatively simple; it displays only minor differences in width and in the arborized epithelium between the isthmus and ampulla, and shows no evidence of the unusual sperm crypts that characterize the isthmus or ampulla, depending on the species, in shrews and moles. In common with other insectivores, Atelerix appears to be an induced ovulator, as judged by the ovulation of some 6-8 eggs by about 23 h after injection of hCG. The dense cumulus oophorus appeared to have little matrix, in keeping with the modest dimensions of the tubal ampulla and, while it was not quite as discrete as that of soricids, it did show the same insensitivity to 0.5% (w/v) ovine or bovine hyaluronidase.

Download Full-text

Identification and fungi toxicity of volatiles in Metasequoia glyptostroboides seeds

CHINESE JOURNAL OF ECO-AGRICULTURE ◽

10.3724/sp.j.1011.2010.01018 ◽

2010 ◽

Vol 18 (5) ◽

pp. 1018-1021

Author(s):

Jun-Jie YANG ◽

Li-Jun CHEN ◽

Hai-Xia YANG ◽

Qing-Feng SHI

Keyword(s):

Metasequoia Glyptostroboides

Download Full-text

Reproductive Characteristics of Winter Wheat Cultivars Subjected to Postanthesis Shading

Crop Science ◽

10.2135/cropsci1990.0011183x003000040002x ◽

1990 ◽

Vol 30 (4) ◽

pp. 771-774 ◽

Cited By ~ 10

Author(s):

L. J. Grabau ◽

D. A. Van Sanford ◽

Q. W. Meng

Keyword(s):

Winter Wheat ◽

Wheat Cultivars ◽

Reproductive Characteristics ◽

Winter Wheat Cultivars

Download Full-text

Analysis of the reproduction mode in Psidium spp. using the pollen:ovule ratio

Acta Scientiarum Agronomy ◽

10.4025/actasciagron.v43i1.44062 ◽

2020 ◽

Vol 43 ◽

pp. e44062

Author(s):

Maria Lorraine Fonseca Oliveira ◽

Telma Nair Santana Pereira ◽

Rodrigo Miranda Barbosa ◽

Alexandre Pio Viana

Keyword(s):

Pollen Grains ◽

Flower Bud ◽

Reproduction Mode ◽

Reproductive Characteristics ◽

Reproduction Strategy ◽

Pollen:Ovule Ratio ◽

Floral Bud

This research aimed to explore the reproductive characteristics of three species of Psidium (P. guajava L., P. cattleyanum Sabine, and P. guineense Sw.) and estimate a probable reproduction strategy based on the pollen:ovule (P:O) methodology. The number of pollen grains per floral bud (NGPB), number of pollen grains per anther (NGPA), number of anthers per flower bud (NAB), number of ovules per flower bud (NOB), and the P:O ratio of each species were estimated. All species had a P:O ratio over 2,000 and were classified as xenogamous. P.guajava presented the highest values for all characteristics evaluated, with the NGPB at 3,777,519, the NOB at 584.50 and a P:O ratio of 6,462.82. Similarly, P. cattleyanum had a P:O ratio of 5,649.89 (NGPB 762,736 and NOB 135). However, P. guineense was considered facultative xenogamous, with P:O of 2,085.75, the NGPB at 741,484 and the NOB at 355.50. Thus, it was concluded that the studied species have a preference for allogamy and require many pollen grains to fertilize each ovule, demonstrating that the transfer of pollen to the stigma is not very specialized.

Download Full-text