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1.
林有润 《植物研究》2002,22(3):341-365
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.
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   

3.
Microbes colonise all multicellular life, and the gut microbiome has been shown to influence a range of host physiological and behavioural phenotypes. One of the most intriguing and least understood of these influences lies in the domain of the microbiome's interactions with host social behaviour, with new evidence revealing that the gut microbiome makes important contributions to animal sociality. However, little is known about the biological processes through which the microbiome might influence host social behaviour. Here, we synthesise evidence of the gut microbiome's interactions with various aspects of host sociality, including sociability, social cognition, social stress, and autism. We discuss evidence of microbial associations with the most likely physiological mediators of animal social interaction. These include the structure and function of regions of the ‘social' brain (the amygdala, the prefrontal cortex, and the hippocampus) and the regulation of ‘social’ signalling molecules (glucocorticoids including corticosterone and cortisol, sex hormones including testosterone, oestrogens, and progestogens, neuropeptide hormones such as oxytocin and arginine vasopressin, and monoamine neurotransmitters such as serotonin and dopamine). We also discuss microbiome‐associated host genetic and epigenetic processes relevant to social behaviour. We then review research on microbial interactions with olfaction in insects and mammals, which contribute to social signalling and communication. Following these discussions, we examine evidence of microbial associations with emotion and social behaviour in humans, focussing on psychobiotic studies, microbe–depression correlations, early human development, autism, and issues of statistical power, replication, and causality. We analyse how the putative physiological mediators of the microbiome–sociality connection may be investigated, and discuss issues relating to the interpretation of results. We also suggest that other candidate molecules should be studied, insofar as they exert effects on social behaviour and are known to interact with the microbiome. Finally, we consider different models of the sequence of microbial effects on host physiological development, and how these may contribute to host social behaviour.  相似文献   

4.
云南干热河谷植被与环境研究进展   总被引:1,自引:0,他引:1  
特殊的地理位置和独特的地形地貌特征组合形成了典型的干热气候环境, 在云南省亚热带高原山地河谷下部发育了一类特有的植被类型, 即干热河谷植被。干热河谷植被具有非地带性和稀有性, 以及由土地利用变化为主的人为活动干扰导致的脆弱性。本文回顾了干热河谷植被的研究历史, 分别从干热河谷的植物群落学和植物区系学、干热河谷植被与土地的关系以及干热河谷植被保护与恢复三个方面进行了总结。植物群落与区系研究主要集中于群落分类、植被分类、群落特征、人为干扰影响、区系特征、性质和起源; 植被与土地关系研究侧重于土壤特性、土地利用/覆盖变化、土地退化及水土流失状况; 植被保护与恢复的热点在植被恢复目标、植被恢复功能区划、植被恢复引种及筛选及植被恢复效益评价研究。未来在这些区域应注重自然灾害及预防、水电工程建设对植被的影响及其响应等方面的研究, 深入开展大尺度植被时空格局的监测和动态服务功能分析。  相似文献   

5.
H. De Haan 《Hydrobiologia》1982,95(1):205-221
This paper attempts to generalize the major controlling factors and their impacts on the physico-chemical environment in Tjeukemeer in relation to the speciation of algal nutrients.Morphometry, man-made hydrology, climate, chemistry of drainage area and biology of the lake appear to control its physico-chemistry the most. Thus the shallow Tieukemeer is vulnerable to wind and therefore almost always completely mixed and often turbid owing to resuspended sediments. In normal summers the lake is oligohaline, hard, eutrophic and alkaline, and in winter it is hard, eutrophic, alkaline and humus-rich. The implications of these properties on the following physico-chemical components and their relevance for the speciation of algal nutrients are discussed: turbidity, colour, halinity, pH, alkalinity, salinity, conductivity, ionic composition, ionic balance and organic matter.Because of the relationships between the physico-chemical environment on the one hand and the speciation and bio-availability of nutrients on the other hand, special attention is given to the speciation of some major and minor elements as derived from ultra filtration experiments. In this context, the metal binding capacity of the organic matter (mainly fulvic acids) is also considered.  相似文献   

6.
口唇部是主要的面部形态区域之一,具有重要的生理功能。嘴唇保护口腔免受外部物质的渗透,维持口腔内部的湿度和温度,帮助咀嚼,同时也是外科美容整形手术中的主要部位之一,且在法医物证研究中唇纹也具有重要的鉴别价值。目前关于口唇部形态的研究主要包括以下几个方面:口唇部形态变异的性别、年龄、族群差异;影响口唇部形态变异的因素,如遗传基因、饮食结构、牙齿及颌骨形态和呼吸方式等;口唇部形态研究在医学、个人身份识别及法医刑侦领域的相关应用等。国内口唇部形态研究相对较少,尤其缺乏较为系统的口唇部形态生长发育及变异研究。本文通过梳理和归纳国内外相关文献的研究数据和结论,对口唇部形态相关研究作简要概述,并对国内口唇部生长发育及形态变异研究作了简要回顾和展望。  相似文献   

7.
Abstract

An introduction to the nomenclature and concept of “Romanowsky stains” is followed by a brief account of the dyes involved and especially the crucial role of azure B and of the impurity of most commercial dye lots. Technical features of standardized and traditional Romanowsky stains are outlined, e.g., number and ratio of the acidic and basic dyes used, solvent effects, staining times, and fixation effects. The peculiar advantages of Romanowsky staining are noted, namely, the polychromasia achieved in a technically simple manner with the potential for stain intensification of “the color purple.” Accounts are provided of a variety of physicochemically relevant topics, namely, acidic and basic dyeing, peculiarities of acidic and basic dye mixtures, consequences of differential staining rates of different cell and tissue components and of different dyes, the chemical significance of “the color purple,” the substrate selectivity for purple color formation and its intensification in situ due to a template effect, effects of resin embedding and prior fixation. Based on these physicochemical phenomena, mechanisms for the various Romanowsky staining applications are outlined including for blood, marrow and cytological smears; G-bands of chromosomes; microorganisms and other single-cell entities; and paraffin and resin tissue sections. The common factors involved in these specific mechanisms are pulled together to generate a “universal” generic mechanism for these stains. Certain generic problems of Romanowsky stains are discussed including the instability of solutions of acidic dye–basic dye mixtures, the inherent heterogeneity of polychrome methylene blue, and the resulting problems of standardization. Finally, a rational trouble-shooting scheme is appended.  相似文献   

8.
IPBES第一轮工作方案受到国际社会的广泛关注,奠定了其作为第一个生物多样性领域政府间机制的重要地位.IPBES自成立以来相继发布了系列评估报告和决策者摘要,引起了国际社会广泛关注,因此,其公平性、公正性、科学性和透明性始终为各界关注的焦点,直接决定着IPBES评估报告的可信度和未来的发展.为有效提升工作效率,提高其成...  相似文献   

9.
中国昆虫染色体研究现状与展望   总被引:12,自引:1,他引:12  
简要叙述了中国昆虫染色体研究的现状,包括研究涉及的昆虫类群、核型分析结果、研究方法和手段、染色体有丝分裂、减数分裂、染色体形态变异、结构变异和数量变异等。我国学者对昆虫染色体研究从20世纪30年代开始,迄今已对蜉蝣目、蜚蠊目、直翅目、半翅目、同翅目、鞘翅目、鳞翅目、双翅目、蚤目和膜翅目等10目481种昆虫的核型进行了研究,主要集中在蝗虫、蝽类、蚜虫、蚕类、果蝇、摇蚊及实蝇等。在染色体行为方面的研究主要有:蚕类和果蝇等有丝分裂;蜚蠊类、蝗类、蝽类和蚕类的减数分裂及性别决定机制;部分昆虫的联会复合体分析。染色体结构变异的研究主要集中在果蝇和蚊类昆虫的唾腺染色体;果蝇的B染色体;蚕类和蚊类昆虫染色体的缺失、易位和倒位等变异;蚕蛾类的数量变异。研究结果多应用于昆虫系统分类和进化的探讨,揭示昆虫遗传与变异规律。通过与国外研究成果对比,提出昆虫染色体研究的必要性,并对我国未来昆虫染色体研究进行了展望。  相似文献   

10.
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12.
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   

13.
郭晓娜  陈睿山  李强  苏维词  刘敏  潘真真 《生态学报》2019,39(17):6567-6575
土地退化已成为威胁32亿人口福祉的全球性重大环境问题之一,近年来受到UN、IPBES、IPCC等组织的广泛关注。然而,当前的土地退化研究中,还存在概念不清、过程和机理不明、影响认识不彻底等问题,因此,厘清土地退化的概念、过程和机制是防止土地退化和恢复退化土地的关键。以生物多样性和生态系统服务政府间科学-政策平台(IPBES)土地退化与恢复专题评估报告为基础,剖析了土地退化的概念、过程、机制及影响:土地退化过程受自然环境和人类活动两大因素驱动,退化过程包括疑似退化、历史退化、敏感退化、弹性退化、持续退化和永久退化6种状态;土地退化类型可根据土地利用类型分为城市土地退化、农田退化、森林与草地退化、湿地退化等;土地退化具有多重影响,包括威胁食物和水安全,影响生物多样性及生态系统服务,引发地区冲突、大规模人口迁徙和疾病传播,加剧贫困及全球气候变化。土地退化过程、机制及影响的审视将为我国沙漠化、石漠化等土地退化的进一步研究提供理论指导,并为我国"山水林田湖草"土地系统的统筹治理和"美丽中国"、"生态文明"建设提供决策支持。  相似文献   

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.
珞巴族与门巴族的体质特征   总被引:4,自引:1,他引:3  
在西藏米林县调查了珞巴族人的67项体质指标, 在错那县调查了门巴族人的67项体质指标, 计算了体质指数, 对珞巴族、门巴族与我国其他人群体质数据进行了比较。研究结果显示: (1)珞巴族男女均为高头型、中面型、中头型(头宽高指数)、中腿型、中胸型、中骨盆型。(2)门巴族男女均为圆头型、高头型、中面型、中鼻型、宽肩型、中胸型、中骨盆型。(3)珞巴族男性、女性均为中等型身高。门巴族男性、女性均为亚中等身高。(4)珞巴族与门巴族蒙古褶率低,上眼睑皱褶率低, 鼻翼高度以中等型率最高, 上唇皮肤部高度以中等型率最高, 发色均为黑色, 眼色褐色率最高, 肤色以黄色率最高。珞巴族耳垂以三角形率最高, 门巴族以圆型率最高。珞巴族、门巴族鼻根高度男性均以中等型率最高, 女性均以低型率最高。(5)珞巴族与门巴族体质特征很接近。他们的头面部特征与甘肃藏族、四川藏族较为接近。珞巴族、门巴族虽生活在我国南方, 体部主要测量指标值与蒙古人种北亚类型接近。  相似文献   

16.
种子品质的优劣对于农牧业生产、经济与遗传资源有效利用、生物多样性保护以及植物群落恢复与重建具有重要的作用.种子老化是其在贮藏过程中普遍存在的一种生理现象,是随着种子贮藏时间延长而发生和发展的自然不可逆过程,不仅关系到后续种、苗生长与产量、品质等问题,还对植物种质资源的保存、利用和开发等均具有重要影响.种子老化的生理机制...  相似文献   

17.
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   

18.
The oldest recorded anthracosaur amphibian Eoherpeton watsoni Panchen, from localities in the Visean and Namurian of the Scottish Carboniferous, is described. It lacks a distinct otic notch, and reconstruction of the position of cranial ligaments and muscles suggest that a tympanum was never developed. On the basis of these observations it is concluded that arguments used to refute a relationship between anthracosaurs and amniotes, based on apparent differences in the morphology of their otic regions, are invalid. The order Anthracosauria is considered to be a monophyletic group characterized by the development of a sutural connection between the tabular and parietal bones on a skull table which includes both the intertemporal and supratemporal as well as the tabular. It is divided into two suborders: Seymouriamorpha characterized by a sutural connection between the squamosal and intertemporal and the presence of a lateral otic tube, and Anthracosauroideae characterized by the absence of post-temporal fossae. The Discosauriscidae, Kotlassiidae and Seymouriidae are included in the Seymouriamorpha, and the Eoherpetontidae, Gephyrostegidae and Embolomeri comprise the Anthracosauroideae. The Proterogyrinidae are considered the most primitive family of embolomeres. A new phylogeny of Amphibia is presented. The old groupings of Labyrinthodontia, Lepospondyli and Lissamphibia are rejected and Amphibia is divided, on the basis of differences in morphology of the neurocranium and its relationship with the surrounding bones of the skull, into two major groups, the first including the Ichthyostcgalia, Temnospondyli, Microsauria and the extant Anura, Apoda and Urodela, while the Aistopoda, Nectridea, Palaeostegalia, Loxommatoidea, Anthracosauria and Diadectomorpha, together with the Amniota, form the second. Similarities in the dentition of the palaeostegalian Crassigyrinus and loxommatoids suggest the two taxa are sister-groups, but the immediate relationships of anthracosaurs remain indeterminate and they here form an unresolved trichotomy with diadectomorphs and amniotes.  相似文献   

19.
The genus Oreocharis as circumscribed here consists of 27 species including 5 varieties, of which 5 species and 4 varieties are described as new in the present paper. In the work analysed were the external morphology and geographic distribution and examined under SEM were pollen exine of 22 species and seed coat of 16 species. As a result, three types of the corolla, two types of the anther, three types of the pollen exine and three types of the seed coat are distinguished here in the paper. It is discovered that the corolla in the genus is relatively stable, though diverse, and highly correlated with the characters of pollen grains and seeds. The corolla clearly bilabiate but constricted at the throat, occurring in O. auricula, O. cordatula, O. aurantiaca, etc., for an example, is correlated with smooth, reticulate pollen exine and partial tectum and the reticulate and smooth seed coat. For this reason the subdivision of the genus in the paper is mainly based on the characters of the corolla, but combined with those of the anther, pollen and seed coat. The genus is divided into four sections in the present classification. Dasydesmus Craib, based on a single species. O. bodinieri, is reduced here, and the reasons are given. The genus is distributed mainly in the subtropics, and less frequently in the tropics, of China south of 32.5°N and east of 98.5°E, with only two species beyond the border, O. hirsuta in Thailand (only a single locality in Chiengmai) and O. aurea also found in north Vietnam (see Fig. 1, Table 3). Sect. 1. Stomactin (Clarke) Fritsch. Corolla urceolate-tubular, constricted at the throat, with limb distinctly bilabiate; anthers broad-oblong; seed coat reticulate, smooth, rarely minutely tuberculate; pollen exine fine-reticulate, tectum partial and smooth, luminae slightly unequal in size. Sect. 2. Orthanthera K. Y. Pan Corolla campanulate or campanulate-tubular; anthers broad-oblong; seed coat reticulate, muri smooth, rarely spiny-processed; pollen exine fine-reticulate, with partial and smooth tectum and luminae slightly unequal in size, rarely exine insular and fine-tuberculate, tectum perforate. Setc. 3. Oreocharis Corolla thin-tubular; anthers broad-oblong; seed coat densely spinyprocessed, rarely fine-tuberculate; pollen exine insular, densely spiny-processed, rarely finereticulate and smooth, luminae unequal in size. Sect. 4. Platyanthera K. Y. Pan Corolla campanulate; anthers hippocrepiform; seed coat densely spiny-processed; pollen exine fine-reticulate, tectum perforate, luminae small, nearly equal in size. In the section Stomactin, although the constriction of corolla at its throat is a specialized character, the characters of seed coat, pollen grains and anthers are apparently primitive. Therefore it may be said at least that more primitive characters are preserved in the section. In the section Oreocharis, on the contrary, the characters of corolla, seed coat and pollen exine are all advanced. And in the section Platyanthera, the seed coat, pollen (with perforate tectum) and anthers have developed rather specialized characters.  相似文献   

20.
The influence of ultraviolet photolysis as a pretreatment to the aerobic and anaerobic biological mineralization of a 14C-polyacrylamide was assessed using a series of radiorespirometry bioassays. The polyacrylamide studied was non-ionic with molecular weights ranging between 100,000 and 1 million. Aerobic and anaerobic biomineralization of the unphotolysed (raw) polyacrylamide was found to be only 0.60% and 0.70%, respectively, after 6 weeks of incubation, and hence indicative of the natural recalcitrance of polyacrylamide to microbial degradation. The effectiveness of UV irradiation in the physical breakdown of the polyacrylamide chain into oligomers was demonstrated by the shift in the molecular weight distribution and the positive correlation between the time of irradiation and the degree of its biological mineralization. The molecular weight fraction below 3 kD, which represents only 2% of the raw polyacrylamide, was increased to 41, 60 and 80% after 12, 24 and 48 hours of photolysis, respectively. This in turn, yielded, after 6 weeks of incubation, an aerobic mineralization of 5, 17 and 29% of 150 mg/L polyacrylamide, respectively, and an anaerobic mineralization of 3, 5 and 17%, respectively. Biomass acclimation substantially improved the specific initial rate of biomineralization of the photolysed polyacrylamides, but not the overall percentage of polyacrylamides mineralized.  相似文献   

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