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1.
略论棕榈科与新分出的省藤科的系统分类、演化、区系地理及主要的经济用途 总被引:6,自引:0,他引:6
棕榈科原省藤亚科因其子房壁及外果皮被倒生、螺旋状排列的鳞片所覆盖,而区别于其他亚科,因而独立分出成一新科--省藤科。作者讨论了棕榈科的祖先种可能在石炭纪时,自原始裸子植物开以顿目在分化、衍生出苏铁目祖先种的进化干上,于白垩纪时分化出的一个分支。在棕榈科的祖先种出现不久后,在其进化的分支上,于白垩纪后期又分化出一旁支,成为棕榈科的姊妹科--省藤科的祖先种。从两祖先种分别再分化、衍生出现今分布地球上该二科的属与种。两科、尤其前者是被子植物、尤其是单子叶植物中最原始的类群之一。作者还提出棕榈科象牙椰亚科与贝叶棕亚科是该科最原始或较原始的两类群;槟榔亚科和腊材榈亚科是较进化的两类群;而水椰亚科祖先种可能源于象牙椰亚科的祖先种,但又演化为该科最进化与特化的类群。省藤科省藤亚科略比鳞果榈亚科原始。作者讨论了两科为泛热带分布的科,指出两科的"现代分布区"在南北两半球热带地区,少数种还延伸分布到两半球暖亚热带、甚至达中亚热带地区,分布区边缘最北达日本中部、中国长江流域及黄河下游的南部,美国加利佛尼亚州与佛罗里达州和地中海北部;最南达智利中部和新西兰南部;而"现代分布中心"在热带与暖亚热带的亚洲,中、南美洲,大洋洲及非洲的东、南、西部;但分布区的"密集中心"则在热带亚洲、热带中及南美洲、南太平洋群岛及非洲东南部。作者还介绍了近50年我国南方引种驯化成功的两科植物近400种(见*图谱),其中少数为耐寒的种类,有的种已引种到长江流域或更北的地区。引种的大部分种都有其重要的经济用途,包括:1. 食用,如淀粉和树液可制"西米"或制糖,酿酒、醋或作饮料;果或种子榨油,供食用或工业用;某些种的嫩芽作蔬菜,甚至种子代咖啡饮用;2. 药用,有消炎、止血、活血、驱虫、抗癌等用;3. 建筑、工艺与日用品,包括不少种的树干供建普通房子、桥梁、小船;少数种可提制工业用蜡;许多种的纤维制高级缆绳和编织品;还制工艺品与日用品等;4. 代表热带景观的园林工程、绿化及美化环境的观赏树和人行道树及建造园林景观生态类型的树种等。 相似文献
2.
Background and Aims A significant number of species assigned to the Neotropical orchid sub-tribe Oncidiinae reward insect pollinators with oil produced in floral glands termed elaiophores. The latter may be glabrous (epithelial elaiophores) or hirsute (trichomal elaiophores). Although the detailed anatomy and ultrastructure of epithelial elaiophores have been studied for a number of genera, such as Oncidium Sw., Gomesa R. Br. and Trichocentrum Poepp. & Endl., hitherto, trichomal elaiophores have been investigated only for a single species of Oncidiinae, Ornithocephalus ciliatus Lindl. Furthermore, this is the only representative of the Ornithocephalus clade to be investigated to date. Here, an examination is made of the elaiophore anatomy and ultrastructure of a further four species currently assigned to this clade (Ornithocephalus gladiatus Hook., Phymatidium falcifolium Lindl., Zygostates grandiflora (Lindl.) Mansf. and Zygostates lunata Lindl.) and the results compared with those obtained for other Oncidiinae. Methods Elaiophore structure was examined for all species at three stages of flower development: closed bud, first day of anthesis and final stage of anthesis, using light microscopy, fluorescence microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. Key Results Elaiophores of O. gladiatus occur upon the lateral lobes of the labellum and display characters intermediate between those of typical epithelial and trichomal elaiophores, in that they are largely glabrous, consisting mainly of cuboidal epidermal cells, but bear short, unicellular hairs proximally. By contrast, the elaiophores of all the other species investigated occur on the callus and are of the trichomal type. In P. falcifolium, these unicellular hairs are capitate. In all species, oil secretion commenced at the closed floral bud stage. Ultrastructurally, the mainly trichomal elaiophores of the four representatives of the Ornithocephalus clade closely resembled the epithelial elaiophores of other Oncidiinae, in that their cells displayed an organelle complement typical of lipid-secreting cells. However, in some taxa, a number of noteworthy characters were present. For example, the elaiophore cuticle of O. gladiatus and P. falcifolium was bi-layered, the outer layer being lamellate, the inner reticulate. The cuticle of Z. grandiflora and Z. lunata was also lamellate, but here, a reticulate layer was absent. Accumulation of secreted oil resulted in the localized distension of the cuticle. Cuticular cracks and pores, however, were absent from all species. The walls of the secretory cells of Z. grandiflora were also atypical in that they had short protuberances or ingrowths, and contained cavities which are thought to be involved in the secretory process. Conclusions Of the species investigated, most displayed similar anatomical organization, their trichomal elaiophores occurring on the labellar callus. They, thus, differ from many other members of the Oncidiinae, where epithelial elaiophores are found either on the callus, or on the lateral lobes of the labellum. However, ultrastructurally, all elaiophores, whether those of representatives of the Ornithocephalus clade, or those of other oil-secreting Oncidiinae, possessed a similar complement of organelles, regardless of whether the elaiophores were trichomal or epithelial. In view of the latter, and the similar chemical composition of oils derived from all Oncidiinae investigated to date, it is probable that position and type of elaiophore, and possibly the structure of the overlying cuticle, play an important role in pollinator selection in these oil-secreting orchids. 相似文献
3.
山东山旺Palaeomeryx化石的初步研究 总被引:2,自引:1,他引:1
Palaeomeryx 在含义、性质和分类位置上,一直是一个争论较多的属.最近在山旺发现的 Palaeomeryx 完整骨架,为解决上述问题提供了有价值的资料和证据. Palaeomeryx 雄性具有一对眶上"皮骨角"和单一的"枕顶角".根据共近裔性状的分析,本文作者认为 Palaeomeryx 应该归入长颈鹿,作为这一支中最早分出的一个旁支.长颈鹿和鹿科有较近的亲缘关系,而和牛科的关系较远. Palaeomeryx 大概位于 Blastomeryx 和 Leptomeryx 之间,从反刍类主干中分出.山旺的材料,代表本属中一个较原始的新种: Palaeomeryx tricornis. 它的时代,可能相当于欧洲的 MN4 或 MN5. 相似文献
4.
The reference ranges of the trace elements Al, As, Be, B, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Li, Rb, Se, Sr, and Zn were determined
by inductively coupled plasma-mass spectrometry (ICP-MS) in sera of a group of free-ranging plains viscachas of the pampa
grasslands of Argentina. The values were compared with those of a small group of captive plains viscachas of the Zurich Zoo
with diabetes and bilateral cataracts. In addition, a method for digestion of whole-blood samples is described for the trace
element determination. Significant differences in the concentration of trace elements in the two groups of animals are discussed.
No correlation was found between the levels of selenium and of other trace elements compared to the formation of cataracts. 相似文献
5.
Tohno Y Tohno S Mahakkanukrauh P Azuma C Vaidhayakarn P Moriwake Y Ohnishi Y Minami T 《Biological trace element research》2003,91(3):217-230
To elucidate quantitative changes of Ca, P, and Mg in the arteries with aging, the authors investigated changes of the mass
ratios of Mg to Ca and P in the arteries of Japanese and Thai by inductively coupled plasma-atomic emission spectrometry.
The arteries of Japanese that were used were the thoracic and abdominal aortas, coronary, common iliac, internal iliac, external
iliac, and femoral arteries, in which very high accumulations of Ca and P occurred in old age. The arteries of Thai that were
used were the abdominal aorta, ramifying site of the abdominal aorta, coronary, common iliac, internal iliac, and external
iliac arteries.
It was found that there were extremely significant correlations both between Ca and Mg contents and between P and Mg contents
in all of the arteries of the Japanese and the Thai. With regard to the mass ratio, the mass ratios of Mg to Ca ranged from
1.5% to 2.1% in the six arteries of the Japanese, except for the thoracic aorta at 3.1%, at an advanced stage of atherosclerosis,
being similar to each other. In the arteries of the Thai, the mass ratios of Mg to Ca ranged from 1.9% to 3.0%, except for
the coronary artery at 0.5%, at an advanced stage of atherosclerosis.
The mass ratios of Mg to P ranged from 2.5% to 2.7% in the six arteries of the Japanese, except for the coronary artery at
1.8%, at an advanced stage of atherosclerosis. With regard to the arteries of the Thai, the mass ratios of Mg to P ranged
from 1.9% to 3.3%, except for the coronary artery at 0.7%, at an advanced stage of atherosclerosis. These results revealed
that both the mass ratios of Mg to Ca and Mg to P were almost similar among the arteries of Japanese and Thai, except for
the coronary arteries. Therefore, these results suggested that the inorganic deposits in the coronary arteries of Japanese
and Thai were similar to those in the intimal tunica of the thoracic aorta, whereas in the other arteries, they were similar
to those in the middle tunica of the thoracic aorta. 相似文献
6.
This study surveys the external morphology of the mouthparts in the guild of spore‐feeders among the coleopterous superfamily Staphylinoidea, evaluating the influence of different phylogenetic and ecological starting points on the formation of their mouthparts. Our emphasis is on a scanning electron microscope analysis (SEM) of the involved trophic structures in spore‐feeding larvae and adults of the Ptiliidae, Leiodidae and Staphylinidae, describing the fine structure of their main functional elements. Functionally, mouthpart structures resemble brushes, brooms, combs, rakes, rasps, excavators, knives, thorns, cram‐brushes, bristle troughs, blocks and differently structured grinding surfaces. Their different involvement in the various aspects of the feeding process (i.e. food gathering, transporting, channelling and grinding) is deduced from our SEM analyses plus direct video observations. We infer five different patterns of food transport and processing, discriminating adults of ptiliids, leiodids plus staphylinids (excluding some aleocharines), several aleocharine staphylinids, and the larvae of leiodids and staphylinids. The structural diversity of the mouthparts increases in the order from (1) Ptiliidae, (2) Leiodidae towards (3) Staphylinidae, reflecting the increasing systematic and ecological diversity of these groups. Comparisons with non‐spore‐feeders show that among major lineages of staphylinoids, shifts from general microphagy to sporophagy are not necessarily constrained by, nor strongly reflected in, mouthpart morphology. Nevertheless, in several of these lineages the organs of food intake and grinding have experienced particular fine‐structural modifications, which have undergone convergent evolution, probably in response to specialized mycophagy such as spore‐feeding. These modifications involve advanced galeal rakes, galeal or lacinial ‘spore brushes’ with arrays of stout bristles, reinforced obliquely ventrad orientated prosthecal lobes and the differentiations of the molar grinding surfaces into stout teeth or tubercles. In addition, several staphylinids of the tachyporine and oxyteline groups with reduced mandibular molae have evolved secondary trituration surfaces, which in some aleocharines are paralleled by considerable re‐constructions of the labium–hypopharynx. 相似文献
7.
8.
Antagonistic factors, broadly identified as antibiosis, competition and natural enemies, impact on entomopathogenic nematodes. Antibiosis can occur through the release of plant chemicals from the roots into the soil, which may adversely affect the host-finding behavior of the infective stage nematode, or the presence of these chemicals in the host insect may negatively affect nematode reproduction. In laboratory studies, intra-specific and inter-specific competition reduces nematode fitness, and inter-specific competition can cause local extinction of a nematode species. For example, after concomitant infection of a host, a steinernematid species usually excludes a heterorhabditid species. The mechanism for the steinernematid superiority has been postulated to be a bacteriocin(s) produced by Xenorhabdus, the symbiotic bacterium of the steinernematid, which prevents Photorhabdus, the symbiotic bacterium of the heterorhabditid, from multiplying. Inter-specific competition between two steinernematid species shows that both can co-exist in a host, but one species will eventually prevail in the environment. By having different foraging strategies, however, both steinermatid species may co-exist in the same habitat. An important issue is whether the introduction of an exotic entomopathogenic nematode species will competitively displace an indigenous nematode species. Although the environmental risks are small, the recommended policy is that the introduction of exotic nematodes be regulated. With other pathogens, entomopathogenic nematodes can out-compete entomopathogenic fungi, but not Bacillus thuringiensis, for the same host individual when both the nematode and entomopathogen are applied simultaneously. The best studied natural enemy is the nematophagous fungus, Hirsutella rhossiliensis, which causes higher mortality in Steinernema glaseri compared with Heterorhabditis bacteriorphora. Differential susceptibility to the fungus may be associated with the retention of the second-stage cuticle by H. bacteriophora. Invertebrate predators including mites and collembolans feed on entomopathogenic nematodes. Although a number of studies have been conducted with antagonists, there is a dearth of field data. We suggest that long-term research plots be established where natural populations of entomopathogenic nematodes occur and include antagonists as a component of such studies. 相似文献
9.
C. J. Tsai S. Kumar B. Ma R. Nussinov 《Protein science : a publication of the Protein Society》1999,8(6):1181-1190
Folding funnels have been the focus of considerable attention during the last few years. These have mostly been discussed in the general context of the theory of protein folding. Here we extend the utility of the concept of folding funnels, relating them to biological mechanisms and function. In particular, here we describe the shape of the funnels in light of protein synthesis and folding; flexibility, conformational diversity, and binding mechanisms; and the associated binding funnels, illustrating the multiple routes and the range of complexed conformers. Specifically, the walls of the folding funnels, their crevices, and bumps are related to the complexity of protein folding, and hence to sequential vs. nonsequential folding. Whereas the former is more frequently observed in eukaryotic proteins, where the rate of protein synthesis is slower, the latter is more frequent in prokaryotes, with faster translation rates. The bottoms of the funnels reflect the extent of the flexibility of the proteins. Rugged floors imply a range of conformational isomers, which may be close on the energy landscape. Rather than undergoing an induced fit binding mechanism, the conformational ensembles around the rugged bottoms argue that the conformers, which are most complementary to the ligand, will bind to it with the equilibrium shifting in their favor. Furthermore, depending on the extent of the ruggedness, or of the smoothness with only a few minima, we may infer nonspecific, broad range vs. specific binding. In particular, folding and binding are similar processes, with similar underlying principles. Hence, the shape of the folding funnel of the monomer enables making reasonable guesses regarding the shape of the corresponding binding funnel. Proteins having a broad range of binding, such as proteolytic enzymes or relatively nonspecific endonucleases, may be expected to have not only rugged floors in their folding funnels, but their binding funnels will also behave similarly, with a range of complexed conformations. Hence, knowledge of the shape of the folding funnels is biologically very useful. The converse also holds: If kinetic and thermodynamic data are available, hints regarding the role of the protein and its binding selectivity may be obtained. Thus, the utility of the concept of the funnel carries over to the origin of the protein and to its function. 相似文献
10.
J.W. Wgele 《Journal of Zoological Systematics and Evolutionary Research》1989,27(4):297-309
Though the interweavement of trophic chains in marine ecosystems of the past cannot be reconstructed, as the abundance, nutrition, reproductive rates and other aspects of the biology of fossil species are not known, it is possible to correlate trends in the evolution of single groups of animals, in the presented case the Crustacea, with the influence of other evolving organisms. The evolution of carnivorous, buoyant, well swimming modern fishes probably induced profound changes in marine ecosystems and influenced the evolution of crustaceans. Indications for these interactions are a. the absence or rare occurrence of defenseless archaic crustaceans in habitats, which are populated by teleostean fishes and the survival of some of these forms in refuges like caves and subterranean waters, and b. the reduction of the pleon in the course of the mesozoic evolution of the Decapoda, which occurs parallel to the radiation of the Teleostei, namely in the period between the early Jurassic and the Tertiary. The shortening of the pleon is interreted as a consequence of the stepwise change from a hyperbenthic to a more benthic Iife-stJe and the abandonment of the caridoid escape reaction. Other adaptations are also construed as results from the selective pressure produced by predators. Extant crustaceans which are able to coexist with fishes, among the macrozoobenthos especially the Decapoda and Peracarida, have a variety of protective adaptations, which help to reduce predation. 相似文献
11.
Cuttings of grapevine (Vitis vinifera L. cv. Chardonnay) were dark-forced at least three weeks. Pigment contents, 77 K fluorescence emission, excitation spectra
of the leaves, petioles, stems, transmission electron micrographs of the etioplasts from leaves, the chlorenchyma tissues
of the stems were analysed. The dark-grown leaves, stems contained 8 to 10, 3 to 5 μg/g fresh weight protochlorophyllide,
its esters, respectively. HPLC analysis showed that the molar ratio of the unesterified, esterified pigments was 7:3 in the
shoot developed in darkness. The dark-forced leaves contained carotenoids identified as: neoxanthin, violaxanthin, antheraxanthin,
lutein, β-carotene. Detailed analyses of the fluorescence spectra proved that all tissues of the dark-forced shoots had protochlorophyllide
or protochlorophyll forms with emission maxima at 628, 636, 644, 655, 669 nm. The 628, 636 nm emitting forms were present
in all parts of the dark-forced shoot, but dominated in the stems, which may indicate an organ specificity of the etioplast
development. Variations in the distribution of the pigment forms were even found in the different tissues of the stem. The
subepidermal layers were more abundant in the 655 nm form than the parenchyma cells of the inner part of the cortex, the pith.
In the latter cells, the plastid differentiation stopped in intermediary stages between proplastids, etioplasts. The plastids
in the subepidermal layers had developed prolamellar body structures, which were similar to those of etiolated leaves. The
results highlight the importance of organ-, tissue specificity of plastid differentiation for chlorophyll biosynthesis, greening
of different plant organs.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
13.
14.
Mt. Wuyi, located at 27°37‛-27°54‛ N, 117°27‛-117°51‛ E, is the highest mountain
in South-East China. Its main peak, Huanggangshan, is 2158 m above the sea level. In 1955, P.
C. Chen organized the first expedition to Mt. Wuyi, and the authors investigated the different
ravines and the forests of that area in 1976 and from 1979 to 1984 respectively. Up to now
355 species of the bryophytes have been found in Mt. Wuyi.
I. The influence of the factors of geological history on the bryoflora of Mt. Wuyi
Fujian Province, belonging to Cathaysian, one of three Chinese ancient lands, was a part
of ocean until the end of the lower Tertiary. In the early Devonian, Fujian uplifted above the
sea level, but it submerged in the sea later, and then uplifted above the sea level again in the
upper Triassic.
By the end of the lower Triassic the Himalayan movement influenced the paleogeography
of China deeply, and the eastern and central mountains of Fujian uplifted again. In the Tertiary, Fujian was influenced by the hot maritime weather, so the tropical evergreen forests existed
in southern Fujian at that time. The conclusion was made by Z. B. Zhao in 1983 after his long
period of study on geological history of Fujian Province since the Yanshan movement.
According to the morden geographical distribution of Chinese bryophytes, it seems that the
above influence might be related to the bryophytes of Mt. Wuyi and also the southern part of
Zhejian Province. By the end of the Tertiary the weather became cold in most parts of China.
Since then the cold weather and hot weather alternated several times. One kind of the endemic elements of the bryoflora formed in the area from the south-eastern coast of China to the
southeastern Xizang (Tibet), including Japan. They are not specialized at the family level or
closely related to each other, but they have similar distribution and belong to different families.
In the Quaternary, Mt. Wuyi gradually uplifted following the Himalayan movement. As the
weather cooled down in the upper part of the mountain, deciduous broad-leaved and needleleaved trees increased there. Meanwhile, temperate genera and species of the bryophytes spread and
invaded South China and entered Mr. Wuyi. Rhytidiadelphus and Hvlocomium probably began to grow in Mt. Wuyi at that time, and their distribution is quite different from their primary one. On the other hand, a part of tropical and subtropical bryophytes might enjoy the
changed weather and environment in the Quaternary and existed in a few small localities of Mt.
Wuyi, and the genera Haplomitrium, Endotrichella and Floribundaria are probably their representatives. From the point of view of geological history we are now living in the interglacial
period and the present natural conditions will last continuously, so they will steadily influence
the bryoflora of Mt. Wuyi in a long period of time.
2. Essential characteristics of the bryoflora in Mt. Wuyi
Due to the geographical position and the other factors of Mt. Wuyi the bryoflora is represented by numerous tropical and subtropical elements (34.1%), but the East-Asiatic endemic ones
(79.2%) are characteristic of the bryoflora in Mt. Wuyi (Tab. 1). The tropical and subtropical
families of the bryophytes, found south of Changjiang (Yangtzi) River, are Haplomitriaceae (1
genus, 3 species), Porellaceae (2 genera, 8 species), Frullaniaceae (2 genera, 10 species), Lejeun eaceae (21 genera, 35 species), Trachypodaceae (3 genera, 4 species), Meteoriaceae (10 genera, 17
species), Neckeraceae (5 genera, 8 species) and Hookeriaceae (3 genera, 3 species). The above
8 families, including 46 genera and 85 species, represent about 1/4 genera (24.3%) and less than
1/4 species (23.9%) of the bryoflora of Mt. Wuyi.
Most species of East-Asiatic elements show very close relationships with Japan, and are
widely distributed from the low altitude of Mt. Wuyi to the summit of Mt. Huanggangshan.
However, the Holarctic species (26.8%) are also important elements of the bryoflora in Mt.
Wuyi, showing its transition nature, although it is located in the subtropics. Moreover, the in fluence of the Himalayas also exists in Mt. Wuyi, and the Himalayan elements cover 14.4% in
the bryoflora of Mt. Wuyi. The similarity coefficients between the bryofloras of Central and
South America, Africa and Oceania and that of Mt. Wuyi are from 5.0-9.2% respectively. The
endemic species are not very many and cosmopolitan species are only 7 there.
In 1958, P. C. Chen designated Mt. Wuyi as “the transition region of South and North
China rich in East-Asiatic genera and species”. His very important conclusion is essentially in
accordance with the fact of the bryoflora on Mt. Wuyi. Recently, some of the new records fur ther show the characteristics of the bryoflora in Wuyi. Two facts are worth being mentioned.
One is that East-Asiatic genera are only five in Mt. Wuyi. However, there are 9 East-Asiatic
genera in Mt. Huangshan more than in Mt. Wuyi; 4 East-Asiatic genera are recorded in Mt.
Shennongjia. The other is that epiphyllous liverworts in Mt. Wuyi, consisting of 7 families, 21
genera and 36 species, are less than on Hainan Island and Xishuangbannan, located in the tro pics in China.
3. Comparison between the bryoflora of Mt. Wuyi and those of the neighbouring regions
As China covers a very large area, bryofloristic elements are quite different in the diffe rent regions. In this section, we are concentrated on making a comparison between the bryof loras of Mt. Wuyi and the regions belonging to the Central China of the bryoflora named by
P. C. Chen.
Huaping Forest Region, Guangxi Zhuang Autonomous Region in South China, with both
latitute and altitude very similar to Mt. Wuyi, is included in this comparison (Fig. 1). According to the rough estimation, the similarity coefficient of moss genera between Mt. Wuyi and
Huaping is 56.3%, and those between the mountain and southern Zhejian and Mt. Huangshan,
Anhui, are 62.7% and 51.6% respectively, while the similarity coefficient of the genera of the
mossfloras between Mt. Shennongjia and Mt. Wuyi is 46.8%. Table 2 shows the statistics of
mosses in Mt. Wuyi and the others, but the bryoflora of Huaping needs further study However,
it is very interesting to note that Haplomitrium and Pleurozia of liverworts are both found in
Mt. Wuyi and Huaping Forest Region, and the similarity coefficient between the mossfloras of
Mt. Wuyi and Zhejian Province is also higher than those mentioned above.
Tropical and subtropical elements reduce towards the north in China, and temperate ones
increase. Huaping is located in the south, and, as expected, some tropical and subtropical
genera such as Hookeriopsis and Symphyodon have been found there, but not in Mt. Wuyi; several
temperate genera, such as Schwetschkeopsis and Fauriella, have been recorded in Mt. Huangshan,
but not in Mt. Wuyi. For some unknown reasons, Octoblepharum and Neckeropsis are only
found in southern Zhejiang, but not in Mt. Wuyi. Mt. Shennongjia, with its main peak over
1000 m higher than that of Mt. Wuyi, is located in its northwest, and more than ten temperate
genera, such as, Ceratodon, Aulacomnium Myurella, Bryonoguchia and Abietinella have been
found there.
Generally, Mt. Wuyi belongs to the central subtropical region of China, and East-Asiatic
endemic genera are the main elements of its bryoflora, but the bryoflora also consists of tropical and subtropical elements with some temperate ones.
4. East-Asiatic endemic genera in the bryoflora of Mt. Wuyi
In the bryoflora of Mt. Wuyi, one of the main elements, East-Asiatic endemic genera, should
not be neglected (Tab. 4). East-Asiatic endemic genera in Mt. Wuyi (five) are less than in Mt.
Huangshan and Mt. West Tianmu, although the positions of the latter two are very close to Mt.
Wuyi. East-Asiatic endemic genera of liverworts are Trichocolea and Macvicaria so far found
in Mt. Wuyi, and the mosses are Myuriopsis, Meteoriella, Pseudospiridentopsis (Fig. 1). Myuriopsis is only distributed in Taiwan Province and Mt. Wuyi, and the other four are distributed in Mt.
Huangshan or Mt. West Tianmu, and also in Taiwan, besides in Mt. Wuyi. About thirty EastAsiatic endemic genera have so far been known in China, which means that about one sixth of
East- Asiatic endemic genera of the bryophytes occur in Mt. Wuyi. We may notice that nine
and seven East-Asiatic endemic genera of the bryophytes have been recorded in Mt. Huangshan
and Mt. West Tianmu respectively. In Mt. Shennongjia, Central China, there are four East
Asiatic endemic genera, but only two have been found in the Huaping Forest Region, South
China. In Mt. Dinghua, located south of Mt. Wuyi, on East-Asiatic endemic genus of the bryophytes has so far been found.
East-Asiatic endemic genera of the bryophytes are mainly limited to China, Korea and Japan,
including the East Himalayas, rarely occur in South Asia, Siberia of the Soviet Union. Therefore,
these genera enjoy a warm and moist environment. In Mt. Wuyi, all the East-Asiatic endemic
genera are monotypic ones with a disjunct distribution. Now in Taiwan Province five of six
recorded East-Asiatic endemic genera are common to Mt. Wuyi. In Japan, about eleven, i.e.
one third of, East Asiatic endemic genera so far found are common to China, which shows a
long history of the phytogeographical relationships between Japan and China. East Asiatic endemic genera of the bryophytes might therefore exist on islands of Taiwan Province and Japan
before they were separated from the mainland of Asia. However the fossil evidence is still
lacking in the bryophytes, so we are not able to discuss about the distribution area and the distribution center of the East-Asiatic bryoflora in detail. The above estimation is more or less
related to geological history, and we assume that the East-Asiatic endemic genera have existed at
least since the end of the Tertiary. Starting from the Quaternary, the climatic change during
glacial epoch has been possibly the most important factor affecting the bryoflora in Asia, and
the upheaval of the Himalayas has stimulated the diversity and the specialization of the bryophy tes. Considering these factors, East-Asiatic endemic genera might be the “Tertiary fossil
plants”.
Another problem is difficult to explain, because Mts. Huangshan, West Tianmu and Shen nongjia were once influenced by glaciation directly, although Chinese geologists hold different
views. However, no evidence of glaciation has been found in Mt. Wuyi. It is worth to study the
close relationships between Mt. Wuyi, Mt. Huangshan and Mt. West Tianmu, where is the distri bution center of the East-Asiatic endemic genera. The above three mountain regions share half
of the East-Asiatic endemic genera, and about 32% genera of the others are found in two of
them (Fig. 2). Myuriopsis, one of the East Asiatic types, was only recorded in Taiwan Pro vince, Japan and Korea. Neodolichomitra, occuring in Taiwan Province, is endemic to China.
More or less the differentiation has taken place in Mt. Huangshan, Mt. West Tianmu and Mt.
Wuyi. The number of the East-Asiatic endemic genera is smaller in Mt. Wuyi, so it is possibly
located on the border of the distributional center of the East-Asiatic endemic genera. Moreo ver, three of four East-Asiatic endemic genera in Mt. Shennongjia are also found in Mt. Huang shan and Mt. West Tianmu, but the other East-Asiatic genus in Mt. Wuyi is common to the
mountain areas in SW China, the Qinglin Range of NW China, and the isolated mountain areas
of NE China. Considering all the characteristics of the bryoflora of Mt. Shennongjia, we assume
that Mt. Shennongjia may belong to another distribution center, including SW part of Sichuan
Province, and the other neighbouring mountains. 相似文献
15.
为阐明3种自然生境下的芦苇适应环境策略,通过设置样地,研究水生、湿生、旱生生境下芦苇的形态性状及生理生态特征,结果表明:(1)芦苇的最高高度、平均高度、最高冠幅、平均冠幅和盖度以水生生境最大,湿生生境次之,旱生生境最小;多度值以旱生和水生生境条件下较大;在水生条件下,芦苇往往形成单优势种群。(2)3种生境中的芦苇横走茎主茎长度不同,随地下水位下降,各分支无性系分株数量、分株高度和叶片数增多,分株距离、分株直径和叶面积减小;随着水分限制的加强,芦苇的节数和根数量增多,节长和根长变短。(3)在旱生生境下,根部和叶部SOD、POD活性和根部CAT活性显著高于水生和湿生,叶部CAT活性旱生显著低于水生。3种生境叶部MDA含量表现为旱生 > 湿生 > 水生,湿生和旱生生境下,根部MDA含量明显高于水生。这些形态性状的差异及生理生态特征可以看作芦苇对3种生境的适应性表现。 相似文献
16.
N.G. Halford T.Y. Curtis N. Muttucumaru J. Postles D.S. Mottram 《The Annals of applied biology》2011,158(1):1-25
We review current knowledge of the most abundant sugars, sucrose, maltose, glucose and fructose, in the world's major crop plants. The sucrose‐accumulating crops, sugar beet and sugar cane, are included, but the main focus of the review is potato and the major cereal crops. The production of sucrose in photosynthesis and the inter‐relationships of sucrose, glucose, fructose and other metabolites in primary carbon metabolism are described, as well as the synthesis of starch, fructan and cell wall polysaccharides and the breakdown of starch to produce maltose. The importance of sugars as hormone‐like signalling molecules is discussed, including the role of another sugar, trehalose, and the trehalose biosynthetic pathway. The Maillard reaction, which occurs between reducing sugars and amino acids during thermal processing, is described because of its importance for colour and flavour in cooked foods. This reaction also leads to the formation of potentially harmful compounds, such as acrylamide, and is attracting increasing attention as food producers and regulators seek to reduce the levels of acrylamide in cooked food. Genetic and environmental factors affecting sugar concentrations are described. 相似文献
17.
中国独龙族与莽人的体质特征 总被引:8,自引:2,他引:6
在云南省贡山县独龙江乡调查了200例(男为97例,女为103例)独龙族人的体质,在金平县金水河镇调查了56例(男33例,女23例)莽人的体质,计算了体质指数,统计了指数分型情况。研究结果显示:1)独龙族、莽人体质特征接近,并与侗、拉祜、彝、德昂族较为一致。2)在蒙古人种南亚类型诸人群中,独龙族、莽人眼内角间宽值较大,而其他多数指标值偏小。3)独龙族男女均以高头型、狭头型、中胸型、中骨盆型率最高。男性还以中头型、狭面型、中鼻型、长躯干型、中腿型、宽肩型率最高。女性还以圆头型、阔面型、狭鼻型、中躯干型、亚短腿型、窄肩型率最高。4)莽人男女均以中头型(头长宽指数)、高头型、中鼻型、中腿型、中胸型、宽肩型、中骨盆型率最高。男性还以中头型(头宽高指数)、阔面型、长躯干型率最高。女性还以狭头型、中躯干型率最高。女性超阔面型率与阔面型率相等。5)独龙族与莽人蒙古褶率低,鼻根高度较低、鼻宽值多大于我国蒙古人种北亚类型诸人群。 相似文献
18.
截至2021年底, 中国共记载591种两栖类(不包括外来入侵种), 是世界上两栖类物种数最多的国家之一。物种特征影响和决定了物种在环境中的生存能力, 在进化生物学、生态学和保护生物学研究中具有重要作用。目前, 中国两栖类在线数据库(https://www.amphibiachina.org )已经整理了我国两栖类的形态特征、生物学信息和地理分布等部分物种特征, 但仍缺乏一个完整的、可自由检索的数据集。通过系统查阅文献和数据检索, 本文收集整理了中国全部591种本土两栖类的22个特征数据, 包括物种发现时间(最早发现和描述新物种文章的发表时间)、模式产地、中国受威胁等级、全球受威胁等级、致危因子、是否中国特有种、是否岛屿特有种、雄性体长、雌性体长、窝卵数、卵径、产卵地点、幼体主要生境、成体微生境、活动模式、生殖周期、繁殖时间、是否有亲本照顾、受精方式、海拔范围、分布地区、分布省份数。除了物种发现时间、是否岛屿特有种、分布地区、分布省份数外, 其余特征数据都有不同程度的缺失, 数据完整度为27.92%-100%, 平均完整度为71.72%, 标准差为24%。本数据集是目前我国两栖类最新和最全的物种特征数据库, 希望可以为我国两栖类生态学、保护生物学、生物地理学等研究提供数据支持。 相似文献
19.
To clarify the effect of aging on the mineral status of female mice, mineral concentrations in their tissues were determined.
Five 2-mo-old, five 6-mo-old, and five 10-mo-old female B10BR mice were fed a commercial diet. Iron, zinc, copper, calcium,
magnesium, sodium, and potassium concentrations in the blood, liver, kidney, heart, brain, lung, and spleen of the mice were
determined using a flame atomic absorption spectrophotometer. Iron concentrations in the liver, kidney, heart, brain, and
spleen increased with age. Significant differences were detected between mice 2 and 6 mo of age and between mice 2 and 10
mo of age. Zinc concentrations in the heart and lung decreased significantly with age. Zinc concentrations in the heart and
lung of 10-mo-old mice were significantly lower than those of 2-mo-old mice. It is noteworthy that the copper concentration
in the brain of 10-mo-old mice was markedly higher compared with that of younger mice. Calcium accumulation was apparent in
the kidney of mice at 10 mo. 相似文献