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1.
Meiosis was studied in the Siberian fir (Abies sibirica Ledeb.) at the arboretum of the Sukachev Institute of Forest. Specific features of meiosis in planted trees have been described. Both general and specific types of irregularities have been identified. The range of irregularities under the arboretum conditions was much wider than in natural ecosystems. 相似文献
2.
Rosanne A. Healy Hannah Zurier Gregory Bonito Matthew E. Smith Donald H. Pfister 《Mycorrhiza》2016,26(7):781-792
During a study comparing the ectomycorrhizal root communities in a native forest with those at the Arnold Arboretum in Massachusetts (USA), the European species Tuber borchii was detected on the roots of a native red oak in the arboretum over two successive years. Since T. borchii is an economically important edible truffle native to Europe, we conducted a search of other roots in the arboretum to determine the extent of colonization. We also wanted to determine whether other non-native Tuber species had been inadvertently introduced into this 140-year-old Arboretum because many trees were imported into the site with intact soil and roots prior to the 1921 USDA ban on these horticultural practices in the USA. While T. borchii was not found on other trees, seven other native and exotic Tuber species were detected. Among the North American Tuber species detected from ectomycorrhizae, we also collected ascomata of a previously unknown species described here as Tuber arnoldianum. This new species was found colonizing both native and non-native tree roots. Other ectomycorrhizal taxa that were detected included basidiomycetes in the genera Amanita, Russula, Tomentella, and ascomycetes belonging to Pachyphlodes, Helvella, Genea, and Trichophaea. We clarify the phylogenetic relationships of each of the Tuber species detected in this study, and we discuss their distribution on both native and non-native host trees. 相似文献
3.
The cytogenetic study of Abies sibirica seed progenies in declining fir stands of West Sayan High Mountains has been carried out. The increased amount of chromosome
and genome mutations, pathologies of mitotic cycle and cells with micronuclei were found at studying. The revealed irregularities
may be the result of a long-term exposure to extreme environmental factors and probably reflect the high degree of disturbance
of the ecosystem in this region. 相似文献
4.
城市森林结构的量化研究——以沈阳树木园森林群落为例 总被引:36,自引:6,他引:36
采用遥感图像判读和野外调查相结合的方法,定量分析了沈阳树木园植物群落的物种结构及空间格局。结果表明,沈阳树木园植被的生长状况良好;物种丰富,其中黄蘖(Phellodendron amugense)、刺槐(Robinia pseudoacacia)、榆树(Ulmus pumila)在树木株数和相对优势度上均占优势,为群落的主林木;植被在高度和胸径上的分布均表现为具有向上发展的潜力,整个植被群落正处于一个快速的生长期,属于发挥生态效益的最佳时期,沈阳树木园的树种多度与基于叶面积的相对优势度之间无明显关联,数量上占优势的树种,其相对优势度不一定很高,沈阳树木园植被树木株数与不同树高等级间的分布关系表现为上凸的曲线,随着树木高度级的增加,树木株数开始分布比较平稳,当高度超过12m后,树木株数明显减少,曲线急骤下降,树木株数分布与不同胸径等级间的关系也呈现类似的情况。 相似文献
5.
Ivana Tomaskova Vaclav Bazant Roman Bleha Jan Vitamvas Sylvain Delzon Karel Stastny Jiri Vackar 《Contemporary Problems of Ecology》2017,10(2):193-202
Four tree species in the Kostelec n. ?. l. arboretum (Czech Republic) have been repeatedly damaged by Dendrocopos medius. The unique aspect of this otherwise common behavior called girdling consists in regularly visiting the same trees every spring, although there are more than 1.200 tree species within the arboretum. We monitored transpiration, leaf phenology and the chemical composition of the xylem sap of girdled and nongirdled trees. Spectral analysis revealed slightly higher amounts of sugars, especially saccharose, in Cladrastis Raf. as the most regularly girdled tree among other conditions, comparing girdled to non-girdled trees. Higher transpiration rates were not confirmed in connection with girdling—quite the opposite—Cladrastis Raf. as the most highly favored tree for girdling showed the lowest transpiration rates (in average 6 kg water per day within spring months) compared to other non-girdled trees. We presume that the birds do not choose a particular tree on the basis of any visible or chemical traits but they examine many trees within their territory. Afterwards they probably remember the position of trees whose xylem sap starts to flow early in the spring compared to other trees, as their transpiration stream is enriched with sweet organic substances that represent an advantage for the forthcoming nesting period. 相似文献
6.
Centaurium pulchellum is an annual herb native to Europe, but introduced in South America, where it is widely used in the preparation of digestive infusions and bitter drinks. In this species, a wide variation in the aperture pattern of pollen grains was reported and has been attributed to environmental factors or irregularities at meiosis. For this reason, cytological and palynological studies have been undertaken on two different populations. The pollen grain analysis showed that some types are more frequent within each population, but the most common forms were the typical 3-colporate and 4-colporate. The cytological analysis revealed that the analyzed populations of C. pulchellum have chromosome number 2n = 36. The presence of tetravalents at meiosis strongly suggests that these populations are autotetraploid based on x = 9. The meiotic behavior showed a significant percentage of irregularities in different phases: off-plate bivalents, precocious segregation, laggard chromosomes, bridges, and cytomixis. However these irregularities are not related to the variation in the aperture pattern of pollen grains. The heteromorphism in the pollen grains observed in C. pulchellum could be a normal condition to which the species is well adapted. 相似文献
7.
Nalaka Geekiyanage Uromi Manage Goodale Kunfang Cao Kaoru Kitajima 《Ecology and evolution》2018,8(1):286-295
Karst hills, that is, jagged topography created by dissolution of limestone and other soluble rocks, are distributed extensively in tropical forest regions, including southern parts of China. They are characterized by a sharp mosaic of water and nutrient availability, from exposed hilltops with poor soil development to valleys with occasional flooding, to which trees show species‐specific distributions. Here we report the relationship of leaf functional traits to habitat preference of tropical karst trees. We described leaf traits of 19 tropical tree species in a seasonal karst rainforest in Guangxi Province, China, 12 species in situ and 13 ex situ in a non‐karst arboretum, which served as a common garden, with six species sampled in both. We examined how the measured leaf traits differed in relation to species’ habitat affinity and evaluated trait consistency between natural habitats vs. the arboretum. Leaf mass per area (LMA) and optical traits (light absorption and reflectance characteristics between 400 and 1,050 nm) showed significant associations with each other and habitats, with hilltop species showing high values of LMA and low values of photochemical reflectance index (PRI). For the six species sampled in both the karst forest and the arboretum, LMA, leaf dry matter content, stomatal density, and vein length per area showed inconsistent within‐species variations, whereas some traits (stomatal pore index and lamina thickness) were similar between the two sites. In conclusion, trees specialized in exposed karst hilltops with little soils are characterized by thick leaves with high tissue density indicative of conservative resources use, and this trait syndrome could potentially be sensed remotely with PRI. 相似文献
8.
9.
Chromosome numbers of 114 individuals from twelve populations ofSedum aizoon L. var.aizoon (Crassulaceae) are reported. They include 37 different chromosome numbers ranging from 2n=71 to 124. Although the chromosome
number variation has been found in all populations examined, no correlation with geographical distribution could not be found.
Various kinds of meiotic irregularities, i.e., multivalents, univalents, chromosome lagging, and polysporous “tetrad” formation
have been found. These irregularities lead to the formation of gametes with various chromosome numbers. All aneuploid plants
set seeds and seem to reproduce sexually. The extensive aneuploidy in var.aizoon seems to be caused by the unequal chromosome segregation in meiosis and the subsequent fertilization of gametes with various
chromosome numbers. 相似文献
10.
The new technique of interspecific hybridization was created in Gossypium, which could remarkably overcome abortion of interspecific hybridization and hybrid sterility of F1. A large number of germplasm resources were obtained from seventy cross combinations among the cultivated species and between the cultivated and the 14 wild species, respectively. 8 varieties have been developed, of which 4 were from the cross combination of G. hirsutumXG. arboretum and the other are the first breed from the hybrids between G. hirsutum and 4 wild species, respectively. Of them Shiyuan 321 (jimian 24) is a new variety which had the highest increase in the national Yellow River Valley Regional test, with planting area added up to 933333 ha in the recent three years. The breeding system of interspecific hybridization was established. 相似文献
11.
Chang KN 《Plastic and reconstructive surgery》2004,114(5):1292-1297
Intraoperative grid pattern markings have been used in the performance of liposuction. Grid pattern markings include series of longitudinal and transverse lines to delineate various anatomical boundaries and landmarks, including the midline, lateral line, and medial line. The markings are superimposed on the customary preoperative markings and divide broad or circumferential body surfaces into smaller subunits for liposuction. Grid pattern markings are applied to areas such as the anterior thighs, medial thighs, entire abdomen, flanks, back, arms, buttocks, calves, and ankles; they are not applied to smaller, less curved areas. Eighty-two consecutive patients underwent lipoplasty in 562 areas of the body. The revision rate for postliposuction contour irregularities was 4.0 percent (nine of 224 areas) where grid pattern markings were used; one area had an indentation type of contour irregularity and required autologous fat grafting. The revision rate was 1.5 percent (five of 328 areas) where grid pattern markings were not used; two areas in one patient had indentation-type contour irregularities and required autologous fat grafting. All remaining areas requiring revision had protuberant-type contour irregularities and responded to additional liposuction only. The use of grid pattern markings is associated with a low incidence of serious contour-related complications. 相似文献
12.
The new technique of interspecific hybridization was created in Gossypium, which could remarkably overcome abortion of interspecific hybridization and hybrid sterility of F1. A large number of germplasm resources were obtained from seventy cross combinations among the cultivated species and between the cultivated and the 14 wild species, respectively. 8 varieties have been developed, of which 4 were from the cross combination of G . hirsutum×G . arboretum and the other are the first breed from the hybrids between G . hirsutum and 4 wild species, respectively. Of them Shiyuan 321 (jimian 24) is a new variety which had the highest increase in the national Yellow River Valley Regional test, with planting area added up to 933333 ha in the recent three years. The breeding system of interspecific hybridization was established. 相似文献
13.
14.
Meiotic restitution is considered to be a common mechanism of polyploidization in plants and hence is one of the most important
processes in plant speciation. Meiotic behaviour of plant chromosomes is influenced by both genetic and environmental factors.
In this study, the meiotic behaviour of cereal crops was investigated, which includes tetraploid wheat genotypes (with and
without the meiotic restitution trait) and their derivates (synthetic hexaploid wheats and a doubled haploid (DH) line), grown
at two planting dates in the field. In addition, two local landraces of emmer wheat (Triticum turgidum ssp. dicoccum), one wheat cultivar (Chinese spring), one DH triticale cultivar (Eleanor) and one rye accession were included. Immature
spikes of mid-autumn and end-winter sowing plants were collected in April and May 2008, respectively, fixed in Carnoy’s solution
and stained with hematoxylin. Pollen mother cells (PMCs) from anthers at different stages of meiotic process were analysed
for their chromosomal behaviour and irregularities. Meiotic aberrations such as laggards, chromosome bridges, micronuclei,
abnormal cytokines, chromatin pulling and meiotic restitution were observed and the studied genotypes were accordingly ranked
as follows: triticale > synthetic hexaploid wheats > tetraploid wheats possessing meiotic restitution > tetraploid wheats
lacking meiotic restitution > rye. The results indicated that the samples that had been planted in the autumn, thus experiencing
an optimum temperature level at the flowering stage, exhibited less meiotic irregularities than winter planting samples that
encountered heat stress at the flowering period. 相似文献
15.
Khaled Sebei Fawzi Sakouhi Wahid Herchi Mohamed Larbi Khouja Sadok Boukhchina 《Biological research》2015,48(1)
Background
In this paper, we have studied the essential oils chemical composition of the leaves of seven Eucalyptus species developed in Tunisia. Eucalyptus leaves were picked from trees growing in different arboretums in Tunisia. Choucha and Mrifeg arboretums located in Sedjnene, region of Bizerte (Choucha: E. maideni, E. astrengens et E. cinerea; Mrifeg : E. leucoxylon), Korbous arboretums located in the region of Nabeul, North East Tunisia with sub-humid bioclimate, (E. lehmani), Souiniet-Ain Drahem arboretum located in region of Jendouba (E. sideroxylon, E. bicostata). Essential oils were individually tested against a large panel of microorganisms including Staphylococcus aureus (ATCC 6539), Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC29212), Listeria ivanovii (RBL 30), Bacillus cereus (ATCC11778).Results
The yield of essential oils ranged from 1.2% to 3% (w/w) for the different Eucalyptus species. All essential oils contain α-pinene, 1,8-cineol and pinocarveol-trans for all Eucalyptus species studied. The 1,8-cineol was the major compound in all species (49.07 to 83.59%). Diameter of inhibition zone of essential oils of Eucalyptus species varied from 10 to 29 mm. The largest zone of inhibition was obtained for Bacillus cereus (E. astrengens) and the lowest for Staphylococcus aureus (E. cinerea). The essential oils from E. maideni, E. astrengens, E. cinerea (arboretum of Bizerte), E. bicostata (arboretum of Aindraham) showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus.Conclusion
The major constituents of Eucalyptus leaves essential oils are 1,8-cineol (49.07 to 83.59%) and α-pinene (1.27 to 26.35%). The essential oils from E. maideni, E. astrengens, E. cinerea, E. bicostata showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus, they may have potential applications in food and pharmaceutical products. 相似文献16.
Investigating the tolerance of plant reproductive systems to environmental changes has become a research priority under current
climate change scenarios. Successful plant conservation requires knowledge of plant reproductive biology, particularly the
meiotic characteristics of planted species. Meiosis, as part of microsporogenesis, is a critical plant developmental stage
controlling future pollen quality. Meiosis in a Siberian fir (Abies sibirica) plantation, established in the Forest Arboretum of the Sukachev Institute, Russia, was studied from 2002 to 2004. The microsporogenesis
pattern found for the Siberian fir appeared to be largely similar to that exhibited by other conifer species. Meiosis in the
Siberian fir has the following characteristics: asynchrony, rapid progression of telophases I and II, and parallel and linear
spindle arrangements at different meiosis II stages. General and specific meiosis irregularities were recorded at each stage.
Some specific features of meiosis and the specific development of some irregularities were revealed. Pollen development analysis
showed that irregular pollen grains made up less than 1% of all grains. The specific features of meiosis identified in fir
trees growing in the Arboretum indicated low resistance of male reproductive structures to climatic changes and might account
for high fir pollen sterility in this new environment. 相似文献
17.
C Giardina G Serio G Simone A Pennella E Vacca R Ricco D Scordari V Pesce Delfino 《Bollettino della Società italiana di biologia sperimentale》1990,66(2):135-141
In this study ten cases of breast infiltrating ductal carcinoma have been considered. In all of them the content of ER has been evaluated by using monoclonal antibodies. Five of them were ER positive and five were ER negative. For the morphometric study ten nuclei of each case have been considered. By using the S.A.M. (Shape Analytical Morphometry) work-station an analytical study of the nuclear shape was performed. The first step was the extraction of fundamental shape which describes the basic shape of original contour without its irregularities. It was obtained by using two parametric equations. The second step was the evaluation of shape asymmetry by S.A.E. (Shape Asymmetry Evaluator). Finally the contour irregularities were evaluated by Fourier analysis. Along with analytical parameters, dimensions (area, perimeter and maximum diameter) were considered too. All obtained data were submitted to univariate statistical analysis (Student's T test) to compare the two groups (ER positive and ER negative tumors). Area, perimeter and maximum diameter were significatively greater in ER negative cases while analytical parameters were not discriminant between the two groups. 相似文献
18.
19.
A. Hore 《Genetica》1981,56(3):205-211
Cytotypes within the genera Seseli L. and Oenanthe L. show variation in chromosome number in pollen mother cells. A correlation of low chiasma frequency with meiotic irregularities and pollen sterility was noted. In addition to the meiotic irregularities in the two genera occurrence of polyspory and triple pollen formation during meiosis have been observed in Seseli diffusum (Roxb.) Sant. Wagh. The presence of different chromosome numbers in different populations of the same species and karyological investigation in 4 species of Oenanthe L. suggests that structural changes of chromosomes associated with numerical differences have possibly played a role in their evolution. Diminution in chromosome size and complete absence of metacentric chromosomes in Oenanthe lachenalli Gmel. suggest that probably this species is more evolved than 3 species of Oenanthe (i.e., O. benghalensis Benth., O. pimpinelloides L. and O. thomsoni Clarke). The interrelationships of the two genera are discussed. 相似文献
20.
M. V. Lebedeva E. A. Levkoev V. A. Volkov A. A. Fetisova S. V. Navalikhin D. A. Shabunin Yu. I. Danilov A. V. Zhigunov E. K. Potokin 《Russian Journal of Genetics》2016,52(10):1046-1055
The genotyping of 75 trees from poplar plantations in St. Petersburg and Leningrad oblast was conducted with microsatellite markers to identify the elite clonal varieties developed by P.L. Bogdanov in the period of 1938–1965. The information about the varieties was lost. The authentic herbarium specimens of poplar clonal varieties preserved at the St. Petersburg State Forest Technical University were used as reference genotypes. According to the results of DNA fingerprinting, we identified the clonal plantations of Populus × newesis Bogd. and Populus × leningradensis Bogd. from the Kartashevskii forest district and the arboretum of the St. Petersburg State Forest Technical University. The identified elite poplar hybrids have a higher frost resistant and a higher growth rate. They are recommended for plantation cultivation in the northwest of Russia. 相似文献