Comparative Reproductive Biology of a Rare Endemic Orchid and its Sympatric Congeners in Southwestern China

This is the first report on chromosome numbers and the reproductive behaviour in Stenodrepanum Harms, a rare endemic and monotypic legume genus from the arid and salty areas of central–western Argentina. Sixty individuals belonging to two populations from two salty areas (“salinas”) were surveyed and included mostly triploid (2n = 3x = 36) and only two diploid (2n = 2x = 24) plants. Meiosis in diploids is regular, with bivalent pairing and uniform and viable pollen. In contrast, meiosis in triploids is characterized by high trivalent pairing, with irregularly shaped pollen and variation in cytoplasm content and stainability, which is in agreement with an unbalanced segregation occurring in anaphases I and II. However, different triploid plants/individuals showed various degrees of pollen fertility, which may be attributed to particular genotypes. Research on reproductive biology events indicates sexual cross-pollinated reproduction enhanced by protogyny in both cytotypes. All plants produced seeds, but seedlings were only recovered from diploid plants pollinated with triploids, and even those eventually perished. Chromosome counts in these seedlings revealed aneuploid chromosome numbers owing to the combination of unbalanced gametes.

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Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157887 ◽

1990 ◽

Vol 48 (3) ◽

pp. 68-69

Author(s):

Alan N. Hodgson

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Fine Structure ◽

Seminal Vesicle ◽

Reproductive Biology ◽

Light Microscope ◽

Light Microscope Level ◽

Transmission Electron ◽

Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

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SGI: A quarter century devoted to excellence in research in reproductive biology

Journal of the Society for Gynecologic Investigation ◽

10.1016/s1071-5576(97)00017-8 ◽

1997 ◽

Vol 4 (2) ◽

pp. 110-110

Author(s):

R LOBO

Keyword(s):

Reproductive Biology ◽

Quarter Century

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Morphology, classification, and reproductive biology ofVigna unguiculata (L.) Walpers (Papilionaceae) in Nigeria

Feddes Repertorium ◽

10.1002/fedr.4911000308 ◽

1989 ◽

Vol 100 (3-4) ◽

pp. 137-145

Author(s):

R. E. Ugborogho ◽

C. O. Agomo

Keyword(s):

Reproductive Biology

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Reconstruction of maximum temperature on Zhegu Mountain, western Sichuan Plateau (China)

Climate Research ◽

10.3354/cr01606 ◽

2020 ◽

Vol 81 ◽

pp. 1-14

Author(s):

M Keyimu ◽

Z Li ◽

Y Zhao ◽

Y Dong ◽

B Fu ◽

...

Keyword(s):

Tree Growth ◽

Ring Width ◽

Volcanic Eruptions ◽

Southwestern China ◽

Maximum Temperature ◽

Driving Mechanism ◽

Western Sichuan ◽

Relationship Analysis ◽

Decadal Scale ◽

Thermal Variability

Historical temperature reconstructions at high altitudes are still insufficient in southwestern China, which is considered one of the most sensitive areas to climate change in the world. Here we developed a tree ring-width chronology of Faxon fir Abies fargesii var. faxoniana at the upper timber line on Zhegu Mountain, Miyaluo Scenic Area, western Sichuan, China. The climate-tree growth relationship analysis indicated temperature as the dominant regulator on radial tree growth in this region. The reconstruction of aggregated maximum temperature (TMX) of autumn and winter for the period 1856-2016 was achieved with a linear regression model that accounted for 43.6% of the actual variability in the common time series (1954-2016). The reconstruction identified 4 warm periods and 3 cold periods. Similarities of warm and cold periods with previously published reconstructions from nearby sites indicated the reliability of our reconstruction. The significant positive correlation between TMX reconstruction and the Asian-Pacific Oscillation index and the Atlantic Multi-decadal Oscillation index suggested a linkage between large-scale climate circulations and the thermal variability at a multi-decadal scale on the western Sichuan Plateau. We also found that solar activity exerted a strong influence on decadal temperature variability in this region. The cold periods were matched well with historical large volcanic eruptions. Our results strengthen the historical climatic information in southwestern China and contribute to further understanding the regional thermal variability as well as its driving mechanism.

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