5 research outputs found
Dormancy breakage in Cercis chinensis seeds
No full textThe seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Seed Coat Anatomy of Cercis chinensis and its Relationship to Water Uptake
No full textThe hard seed coat of Cercis chinensis Bunge is an important cause of its dormancy. A study of the characteristics of water absorption is vital for understanding seed dormancy and germination. This investigation found that soaking in water at an initial temperature of 80 C for 5 min was optimum in breaking the hardness of C. chinensis seeds. Scanning electron microscopy (SEM), dye-tracking and blocking experiments were used to examine the major water entry sites and the relationship between water uptake and seed coat structure during C. chinensis seed imbibition. The SEM images showed that the seed coat consisted of three layers: epidermis, palisade and sclereid. Special light line, vascular bundle and counter-palisade layer structures were found in the side of the hilum. The blocking experiments showed that the hilar region was the important water absorption site because, if the region was not blocked, it showed the highest water absorption when imbibed for 3–12 h. However, all parts of the seed coat can absorb water if enough time is allowed after the seed coat hardness has been broken. The dye-tracking test showed that, after 3 h, water entered the seed only via the hilum fissure. Therefore, the hilum fissure acts as the initial site of water absorption. When more time was allowed, water moved more rapidly on the side having vascular bundles than on the opposite side.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
THE OEDIPUS COMPLEX IN THE FROG BY JOHN HAWKES
No full textThe Frog is one of the well-known novels written by John Hawkes in 1996 which is narrated by the main character Pascal. The novels by John Hawkes which are the results of conscious rejection of the traditional realistic are accepted unusual and avant-garde by great numbers of literary critics. John Hawkes focuses on certain themes such as love, morality, unsatistaction, and erotism via adopting peculiar methods to show how a writer can exceed the limits. In The Frog the author demonstrates how a young boy who feels an overwhelming obsessive desire to his mother develops a behaviour characterized by love, hatred, satisfaction, dissatisfaction, trust, and obsession towards the people around him in some manner. That obsession which is called Oedipus Complex was introduced by an Austrian neurologist Sigmund Freud in 1899. Despite the fact that the first chapter of the novel is devoted to indicate Pascal has a wonderful childhood and acquaint the reader with the peaceful home in which he lives, he, still, encounters some difficulties which are resulted by his obsession of his mother. One of the main reasons of these difficulties he encounters is the reality of Pascal is exposed to some short stories were read aloud by his mother and he was influenced by these stories profoundly. The stories he listens about the frogs on a daily basis make Pascal to have a great interest in frogs which are going to alter his life dramatically in the long term. When he thinks he swallowed a frog which lives in his abdomen in times to come, his attitudes considerably change, his obsession with his mother gets bigger unlike he starts to loathe his father more. For that matter Pascal’s life comes under the influence of his obsessions. In this article we will discuss Pascal’s behaviours and how they are shaped by his excessive love of his mother to reach a deeper understanding about the Freudian Oedipus Complex syndrome in the novel
First record of the seed beetle Bruchidius siliquastri (Coleoptera, Chrysomelidae, Bruchinae) from Greece
No full textBruchidius siliquastri Delobel, 2007, a chrysomelid species presumably of East Asian origin, is recorded for the first time in Greece. It is regarded as an invasive species in Europe that feeds on the seeds of Cercis siliquastrum L. (Fabaceae). The species distribution and ecology are briefly discussed. An additional record of Bruchidius terrenus (Sharp 1886) in Greece is also provided. Copyright Gastouniotis, Boulas & Gastouniotis. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Long-term CO2 enrichment of a forest ecosystem : implications for forest regeneration and succession
No full textAuthor Posting. © Ecological Society of America, 2007. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 17 (2007): 1198–1212, doi:10.1890/05-1690.The composition and successional status of a forest affect carbon storage and net ecosystem productivity, yet it remains unclear whether elevated atmospheric carbon dioxide (CO2) will impact rates and trajectories of forest succession. We examined how CO2 enrichment (+200 μL CO2/L air differential) affects forest succession through growth and survivorship of tree seedlings, as part of the Duke Forest free-air CO2 enrichment (FACE) experiment in North Carolina, USA. We planted 2352 seedlings of 14 species in the low light forest understory and determined effects of elevated CO2 on individual plant growth, survival, and total sample biomass accumulation, an integrator of plant growth and survivorship over time, for six years. We used a hierarchical Bayes framework to accommodate the uncertainty associated with the availability of light and the variability in growth among individual plants.
We found that most species did not exhibit strong responses to CO2. Ulmus alata (+21%), Quercus alba (+9.5%), and nitrogen-fixing Robinia pseudoacacia (+230%) exhibited greater mean annual relative growth rates under elevated CO2 than under ambient conditions. The effects of CO2 were small relative to variability within populations; however, some species grew better under low light conditions when exposed to elevated CO2 than they did under ambient conditions. These species include shade-intolerant Liriodendron tulipifera and Liquidambar styraciflua, intermediate-tolerant Quercus velutina, and shade-tolerant Acer barbatum, A. rubrum, Prunus serotina,Ulmus alata, and Cercis canadensis. Contrary to our expectation, shade-intolerant trees did not survive better with CO2 enrichment, and population-scale responses to CO2 were influenced by survival probabilities in low light. CO2 enrichment did not increase rates of sample biomass accumulation for most species, but it did stimulate biomass growth of shade-tolerant taxa, particularly Acer barbatum and Ulmus alata. Our data suggest a small CO2 fertilization effect on tree productivity, and the possibility of reduced carbon accumulation rates relative to today's forests due to changes in species composition.This research was supported by the
Office of Science (BER), U.S. Department of Energy, Grant
No. DE-FG02-95ER62083, and by Terrestrial Ecosystems and
Global Change (TECO) Grant No. DE-F602-97ER62463
