In situ reproductive organs of Early Cretaceous ferns from Northeast China

1997 ◽  
Vol 42 (23) ◽  
pp. 1977-1980 ◽  
Author(s):  
Deng Shenghui ◽  
Chen Fen
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Reproductive Organs

scholarly journals Distribution of Potato spindle tuber viroid in Reproductive Organs of Petunia During Its Developmental Stages

2014 ◽  
Vol 104 (9) ◽  
pp. 964-969 ◽  
Author(s):  
Yosuke Matsushita ◽  
Shinya Tsuda
Keyword(s):  
Developmental Stages ◽  
Cell Movement ◽  
Seed Transmission ◽  
Potato Spindle Tuber Viroid ◽  
Reproductive Organs ◽  
Infected Male ◽  
Infected Female ◽  
Reproductive Tissues ◽  
Healthy Female

Embryo infection is important for efficient seed transmission of viroids. To identify the major pattern of seed transmission of viroids, we used in situ hybridization to histochemically analyze the distribution of Potato spindle tuber viroid (PSTVd) in each developmental stage of petunia (flowering to mature seed stages). In floral organs, PSTVd was present in the reproductive tissues of infected female × infected male and infected female × healthy male but not of healthy female × infected male before embryogenesis. After pollination, PSTVd was detected in the developed embryo and endosperm in all three crosses. These findings indicate that PSTVd is indirectly delivered to the embryo through ovule or pollen during the development of reproductive tissues before embryogenesis but not directly through maternal tissues as cell-to-cell movement during embryogenesis.

scholarly journals Male spike strobiles withGnetumaffinity from the Early Cretaceous in western Liaoning, Northeast China

2009 ◽  
Vol 47 (2) ◽  
pp. 93-102 ◽  
Author(s):  
Shuang-Xing GUO ◽  
Jin-Geng SHA ◽  
Li-Zeng BIAN ◽  
Yin-Long QIU
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Western Liaoning

scholarly journals Micropaleontology and palaeoclimate during the early Cretaceous in the Lishu depression, Songliao basin, Northeast China

2017 ◽  
Vol 8 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Wei Yan ◽  
Tailiang Fan ◽  
Hongyu Wang ◽  
Chen Zhu ◽  
Zhiqian Gao ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Songliao Basin

Reproduction in the Female White-Striped Mastiff Bat, Tadarida australis (Gray) (Molossidae)

1982 ◽  
Vol 30 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Kitchener ◽  
CJ Hudson
Keyword(s):  
Reproductive Tract ◽  
Reproductive Organs ◽  
Uterine Horn ◽  
Museum Specimens ◽  
Histological Techniques ◽  
Lactating Females ◽  
Young Of The Year ◽  
The Right ◽  
Reproductive Phases

The reproductive cycle of female T, australis is outlined from examination of reproductive organs in situ and from histological techniques on museum specimens collected in Australia, south of latitude 22�S., over the last 88 years. Features of the reproductive tract and ovaries during important repro- ductive phases are described. There is a marked asymmetry of the reproductive organs, only the right ovary and uterine horn being functional. T. australis is monoestrous; there is no indication of marked differences in the timing of reproductive phases between regional populations. A single, deeply embed- ded corpus luteum occupies up to 60% of the ovary and degenerates at about the time of parturition. Apparently, most females, including young of the year, become pregnant each year, and give birth to a single young, usually between mid-December and late January, although occasionally as late as the end of February. Most young are weaned by early May. There is a short anoestrus, which is probably restricted to early lactating females, followed by a relatively long pro-oestrus. Copulation, ovulation and fertilization occur around late August. There is no evidence of hibernation.

scholarly journals Vertical transmission of Prunus necrotic ringspot virus: hitch-hiking from gametes to seedling

2009 ◽  
Vol 90 (7) ◽  
pp. 1767-1774 ◽  
Author(s):  
Khalid Amari ◽  
Lorenzo Burgos ◽  
Vicente Pallás ◽  
Maria Amelia Sánchez-Pina
Keyword(s):  
Vertical Transmission ◽  
Developmental Stages ◽  
Embryo Sac ◽  
Reproductive Organs ◽  
Ringspot Virus ◽  
Reproductive Tissues ◽  
Hand Pollination ◽  
Prunus Necrotic Ringspot Virus ◽  
High Concentrations

The aim of this work was to follow Prunus necrotic ringspot virus (PNRSV) infection in apricot reproductive tissues and transmission of the virus to the next generation. For this, an analysis of viral distribution in apricot reproductive organs was carried out at different developmental stages. PNRSV was detected in reproductive tissues during gametogenesis. The virus was always present in the nucellus and, in some cases, in the embryo sac. Studies within infected seeds at the embryo globular stage revealed that PNRSV infects all parts of the seed, including embryo, endosperm and testa. In the torpedo and bent cotyledon developmental stages, high concentrations of the virus were detected in the testa and endosperm. At seed maturity, PNRSV accumulated slightly more in the embryo than in the cotyledons. In situ hybridization showed the presence of PNRSV RNA in embryos obtained following hand-pollination of virus-free pistils with infected pollen. Interestingly, tissue-printing from fruits obtained from these pistils showed viral RNA in the periphery of the fruits, whereas crosses between infected pistils and infected pollen resulted in a total invasion of the fruits. Taken together, these results shed light on the vertical transmission of PNRSV from gametes to seedlings.

Dates and rates in ancient lakes: 40Ar–39Ar evidence for an Early Cretaceous age for the Jehol Group, northeast China

1995 ◽  
Vol 32 (9) ◽  
pp. 1426-1431 ◽  
Author(s):  
Patrick E. Smith ◽  
Norman M. Evensen ◽  
Derek York ◽  
Mee-Mann Chang ◽  
Fan Jin ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Northeast China ◽  
Late Jurassic ◽  
Lacustrine Sediments ◽  
Yixian Formation ◽  
Liaoning Province ◽  
Absolute Calibration ◽  
Small Fault ◽  
Absolute Age ◽  
Good Agreement

The correlation of freshwater sediments in small, fault-bound basins in Liaoning Province, northeast China, known as the Jehol (or Rehe) Group, has been a subject of debate for many years, with biochronological estimates ranging from Late Jurassic to the Cretaceous periods. We have applied the laser 40Ar–39Ar technique to volcanic intercalations and lacustrine sediments from the Yixian Formation at the base of the Jehol Group. Minerals and whole-rock chips from the upper parts of the Yixian Formation give concordant ages with a mean of 121.1 ± 0.2 Ma (1σ). Ages for samples near the base of the Yixian Formation give 121.4 ± 0.6 and 122.9 ± 0.3 Ma, and appear to be synchronous or only slightly older than the top of the formation. Integrated ages of 122 Ma for glaucony from the lacustrine sediments lying stratigraphically between the upper and lower parts of the Yixian are in very good agreement with the absolute age framework provided by the volcanic units. Such disseminated facies of this clay show promise for directly dating lacustrine sediments. All of the above 40Ar–39Ar dates provide an absolute calibration of the Yixian Formation, and show that the whole formation was deposited entirely within Early Cretaceous time over an interval of no more than 2–3 Ma.

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