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1.
中国南部斑腿蝗科四属昆虫的支序生物地理学研究   总被引:4,自引:0,他引:4  
在中国南部斑腿蝗科4属昆虫种间系统发育关系及物种地理分布研究的基础上,划分出10个特有分布区。用支序生物地理学软件COMPONENT2.0,处理了上述蝗虫种间系统发育关系和地理分布资料所组成的数据,以明确各特有的分布区的历史生物地理学关系。结果表明,10个特有分布区形成的先后是:云南南部和黄土高原两个分布区,海南岛区,东部山地区,台湾岛区;云贵高原、云南北部和秦巴山区几乎是同时形成的,而华南和江南丘陵区形成最晚。  相似文献   

2.
陕西汉中地区蝗虫种类及区系特点   总被引:3,自引:0,他引:3  
张宏杰  霍科科 《昆虫知识》2005,42(5):562-565
汉中地区的蝗总科昆虫有5科33属51种,锥头蝗科Pyrgomorphidae1属2种,斑腿蝗科Catantopidae9属19种,网翅蝗科Arcypteridae5属12种,斑翅蝗科Oedipodidae12属13种,剑角蝗科Acrididae5属5种。汉中地区蝗总科的昆虫以东洋界为主,共23种,占45.1%,其次为汉中地区特有种类10种,占19.6%,古北界和两界共有种类均为9种,均占17.6%。物种数量在各县区分布不均匀。  相似文献   

3.
中国种子植物物有属的分布区学研究   总被引:1,自引:0,他引:1       下载免费PDF全文
本讨论了分布区的概念和分布区周界的划究方法,认为邻近距离平均法对划定分布区的周界具有较大的科学性和可用性。根据247幅中国种子植物特有属的分布区图及其属内各种在属分布区范围内的分布情况,我们将中国种子植物特有属划分为5个分布区类型。本还对中国种子植物特有属分布区和地形和气候条件的关系,以及与植被和植物区系界线的关系进行了分析,提出制约分布区形状和大小的主要决定因素,并指出种在属分布区内的分布规  相似文献   

4.
甘肃省忍冬属植物区系地理的定理研究   总被引:2,自引:0,他引:2  
根据系统分类和地理分布资料,采用模糊聚类方法,将甘肃省所产忍冬属41个类群划分为18个地理范畴各异的分布式样,分别归属于中国特有,东亚、中国-日本、中国-鼓马拉雅、热带亚洲,西亚喜马拉雅至东亚北部等6个分布型,其中,中国特有分布类群占73.2%。多数分布式样体现出西南至东北部的适应性辐射方向,少数呈现山西至西北方向。将甘肃省忍冬属植物分布区划分为3个区,11个小区,其中白龙江中上游山地,小陇山微成  相似文献   

5.
中国斑蚜科物种多样性及地理分布格局   总被引:5,自引:4,他引:1  
从分类群的多样性、寄主植物多样性和地理分布多样性3个方面系统研究了中国斑蚜科蚜虫的物种多样性。分类群的多样性从亚科、属和种3个不同阶元进行了描述。寄主植物的多样性体现在:不同蚜虫类群寄主植物的丰富度,其中角斑蚜亚科的寄主最为丰富,包括14个科的植物;同类寄主植物上取食蚜虫的多样性,其中桦木科植物上有15个属的蚜虫取食。在地理分布上,斑蚜科在中国主要分布在古北界的4个区和东洋界的3个区,以古北界的成分占优势;而且华北区种类最为丰富,其次为东北区、华中区、华南区和蒙新区。属的分布类型可分为12种,分别为中国特有分布型、东亚特有分布型、古北界特有分布型、东洋界特有分布型、全北界分布型、全北界和澳洲界共有分布型、古北界和东洋界共有分布型、全北界和东洋界共有分布型、全北界和非洲界共有分布型、古北界、东洋界和非洲界共有分布型、东洋界和澳洲界共有分布型及东洋界、非洲界和澳洲界共有分布型,其中以东亚特有分布型为最丰富,有10个属;其次为全北界分布型,有7个属,同时中国的特有成分也相当高,涉及6个属。纵观整个中国斑蚜科属级阶元的分布类型,中国的斑蚜科以全北界成分为主,其次为东洋界成分。斑蚜科在中国的地理分布,由东向西,种类越来越贫乏,特别是青藏高原,种类很少;从南北向来看,以华北区为中心,向两边扩散,东北区、华南区和华中区种类都有所减少。  相似文献   

6.
中国种子植物特有属的分布区学研究   总被引:11,自引:0,他引:11       下载免费PDF全文
本文讨论了分布区的概念和分布区周界的划定方法,认为邻近距离平均法(mean propinquity method)对划定分布区的周界具有较大的科学性和可用性。根据247幅中国种子植物特有属的分布区图及其属内各种在属分布区范围内的分布情况,我们将中国种子植物特有属划分为5个分布区类型。本文还对中国种子植物特有属分布区与地形和气候条件的关系,以及与植被和植物区系界线的关系进行了分析,提出制约分布区形状和大小的主要决定因素,并指出种在属分布区内的分布规律的研究对次一级植物区系分区或植被区划研究具有重要意义。  相似文献   

7.
江西三清山维管束植物区系分析   总被引:2,自引:0,他引:2  
三清山位于赣东北怀玉山脉东端,维管束植物繁多,有193科878属1 915种。通过分析科、属、种的分布区类型,结果表明:科的分布区类型以泛热带分布最多(34.2%),其次为世界分布(31.09%)和北温带分布(15.03%),温带分布少于热带分布(41∶90);属的分布区类型以北温带分布最多(17.88%),其次为泛热带分布(14.81%)和东亚分布(12.76%),温带分布多于热带分布(427∶341);种的分布区类型以中国特有分布最多(48.92%),其次为东亚分布(30.73%)和热带亚洲分布(6.73%),温带分布远多于热带分布(705∶245),表明该区植物区系具有明显的亚热带山地植物区系性质。以区系分区区划作为分析地理分布特征的单位,将三清山的中国特有分布型划分为12个亚型,以华东—华中—西南(华南)分布亚型所占比例最大,反映出各区系间联系密切。  相似文献   

8.
本文探讨了中国斑腿蝗科属级分布特征和区系组成特点.结果表明:在我国有分布的斑腿蝗科101个属级阶元中,东洋区成分为62属,占已知属总数的61.4%;其次依次为双区属18属,占17.8%;古北属15属,占14.9%;广布属6属,仅占5.9%;有48属为我国特有属,占总数的47.5%.根据其属级阶元在世界各大动物地理区的分布比较发现我国的斑腿蝗科昆虫与非洲共有性较高,两者亲缘关系相对较近.  相似文献   

9.
四川分布的中国种子植物特有科属研究   总被引:9,自引:2,他引:7  
对传统“特有”概念作了补充说明,确认四川有中国种子植物特有类群129属,12个特有科,在国产特有类群中占有较大比例。生活型虽然以草本为主,但高比例(近1/3)的木本类型以及木本类型多为原始的古特有成分却反映出植物区系的古老性和悠久发展历史。地理分布以盆地四周山地最丰富,西部高原和盆地中部缺乏或少有特有科、属。总体上可划分为3个分布中心区,包括西南区、东南区和东北区。新特有成分以西南区较多,而古特有成分大多集中中东南区和东北区。特有属与邻近地区的相似性还反映了四川植物区系和邻近地区植物区系的整体性。丰富的特有科、属同时也反映出四川种子植物区系的多样性。  相似文献   

10.
试论中国种子植物特有属的分布区类型   总被引:39,自引:3,他引:36  
中国种子植物特有属是局限分布于中国行政区域范围内的植物成分,就其分布特点看,集中分布于中国南部亚热带广阔区域。由于中国地域广袤,虽然大多数特有属分布在东亚自然地域范围内,但南部特有属的分布范围已进入古热带植物区的马来亚森林植物亚区的北部,而西部的特有属的分布范围已进入青藏高原地区。局限于不同地域分布的特有属,各自的起源发生、所经历的地质历史过程存在一定差别。本文以自然地理区划作为研究中国种子植物特有属分布区类型的依据,将中国特有属分布区类型划分为中国东部和中部特有分布变型、中国南部特有分布变型、中国西部特有分布变型和中国北部特有分布变型4类。其中中国南部特有分布变型所含特有属为热带区系成分,其它3个特有分布变型所含特有属为温带区系成分。这样能较客观地反映中国特有属的自然地理特征,有利于研究局部地区植物区系的地质历史演变过程。  相似文献   

11.
心脑血管疾病大额住院消费统计分析   总被引:1,自引:1,他引:0  
通过对医院2004-2006年心脑血管疾病大额住院消费(消费大于50000元,以下简称大额消费)病例发病率高的前五种疾病的构成情况、药费、材料费消耗情况进行分析,认为加强大额病例中发病率高的病种的重点管理,是降低医疗费用的有效途径。建议制定常见病大额病种预定额付费方案和审查报销制度;采用适宜技术;控制药费,防止过度医疗,有效地遏制医疗费用的过快增长。  相似文献   

12.
Although the architecture of tripartite multiple drug resistance (MDR) efflux pumps of Gram-negative bacteria has been well characterized, the means by which the components recognize each other and assemble into a functional pump remains obscure. In this study we present evidence that the C-terminal domain of the Pseudomonas aeruginosa OprM and the α-helical hairpin domain of Vibrio cholerae VceA play an important role in the recognition/specificity/recruitment step in the assembly of a functional, VceAB-OprM chimeric efflux pump. To our knowledge, this is the first evidence directly linking the C-terminal domain of an outer membrane efflux protein to its recruitment during the assembly of a tripartite efflux pump.  相似文献   

13.
对不同地理分布的猪苓纯培养菌株进行了种性和酯酶同工酶的比较研究,结果表明,鸡爪苓(Z)纯培养菌株和猪屎苓(ZJ)纯培养菌株的种性有很大不同,两个纯培养菌株的酯酶同工酶酶带类型差异较大,亲缘关系较远。  相似文献   

14.
New analogues of the Gly-Pro-Arg and Arg-Gly-Asp fragments of fibrinogen were synthesized: Gly-Pro-Arg-Pro (I), Gly-Pro-Arg-Pro-Met-OMe (II), Gly-Pro-Arg-Pro-Phe (III), Gly-Pro-Arg-Pro-Asp (IV), Gly-Pro-Arg-Pro-Glu (V), and Arg-Asn-Trp-Asp (VI). Their effect on the activity of proteases of various types was studied with the method of lysis of fibrin plates. All the peptides were found to inhibit plasmin activity (by 60–85%) and the γ-subunit of nerve growth factor (by 55–93%). Tetrapeptide (VI) proved to be an effective inhibitor of tissue activator of plasminogen and the γ-subunit of nerve growth factor (by 96 and 93%, respectively). The peptides exerted practically no effect on the activity of urokinase and moderately inhibited the activity of streptokinase [(III), IV), and (VI)], papain [(I), (II), IV), and (VI)], subtilisin [(V) and (VI)], α-chymotrypsin [(III), (V), and VI)], and Bacillus subtilis metalloprotease (VI). They inhibit trypsin [except for (I) and (III)] when applied on fibrin plates at a concentration of 1 × 10?2 M, while, at the concentration of 1 × 10?3 M, (I) and (II) induced an increase in proteolytic activity by 35 and 47%, respectively.  相似文献   

15.
J.Michael Gould  S. Izawa 《BBA》1974,333(3):509-524
1. By using dibromothymoquinone as the electron acceptor, it is possible to isolate functionally that segment of the chloroplast electron transport chain which includes only Photosystem II and only one of the two energy conservation sites coupled to the complete chain (Coupling Site II, observed P/e2 = 0.3–0.4). A light-dependent, reversible proton translocation reaction is associated with the electron transport pathway: H2O → Photosystem II → dibromothymoquinone. We have studied the characteristics of this proton uptake reaction and its relationship to the electron transport and ATP formation associated with Coupling Site II.

2. The initial phase of H+ uptake, analyzed by a flash-yield technique, exhibits linear kinetics (0–3 s) with no sign of transient phenomena such as the very rapid initial uptake (“pH gush”) encountered in the overall Hill reaction with methylviologen. Thus the initial rate of H+ uptake obtained by the flash-yield method is in good agreement with the initial rate estimated from a pH change tracing obtained under continuous illumination.

3. Dibromothymoquinone reduction, observed as O2 evolution by a similar flash-yield technique, is also linear for at least the first 5 s, the rate of O2 evolution agreeing well with the steady-state rate observed under continuous illumination.

4. Such measurements of the initial rates of O2 evolution and H+ uptake yield an H+/e ratio close to 0.5 for the Photosystem II partial reaction regardless of pH from 6 to 8. (Parallel experiments for the methylviologen Hill reaction yield an H+/e ratio of 1.7 at pH 7.6.)

5. When dibromothymoquinone is being reduced, concurrent phosphorylation (or arsenylation) markedly lowers the extent of H+ uptake (by 40–60%). These data, unlike earlier data obtained using the overall Hill reaction, lend themselves to an unequivocal interpretation since phosphorylation does not alter the rate of electron transport in the Photosystem II partial reaction. ADP, Pi and hexokinase, when added individually, have no effect on proton uptake in this system.

6. The involvement of a proton uptake reaction with an H+/e ratio of 0.5 in the Photosystem II partial reaction H2O → Photosystem II → dibromothymoquinone strongly suggests that at least 50% of the protons produced by the oxidation of water are released to the inside of the thylakoid, thereby leading to an internal acidification. It is pointed out that the observed efficiencies for ATP formation (P/e2) and proton uptake (H+/e) associated with Coupling Site II can be most easily explained by the chemiosmotic hypothesis of energy coupling.  相似文献   


16.
林带阻力系数与透风系数关系的理论分析   总被引:15,自引:2,他引:13  
根据冲量定理分析了林带对气流的阻力,首次得到了林带阻力系数的估算模式(Cd=(1.8+0.2α)(1-α)sin2ω,并利用有关文献发表的资料进行了验证.文章还对来流平行林带时林带对气流的阻力进行了讨论,指出来流平行林带时林带对气流的阻力仅为来流垂直林带时林带对气流阻力的0.7—1.1%,可以不予考虑.  相似文献   

17.
该研究于西藏自治区东南部的东达山高山草甸沿生境干旱化梯度设置10个样地,采用线性回归方法分析优势种高山嵩草(Kobresia pygmaea)和矮生嵩草(K.humilis)叶片数量与其它构件数值(分株数量、茎基直径、根系数量和根系长度)之间的关系,并采用线性回归斜率测度分株功效、叶片萌生能力、根系分生功效和根系伸长功效,以探讨嵩草的分株能力、茎基生长和根系生长对生境干旱化过程的响应机制。结果显示:(1)2种嵩草植物的叶片数量与4种构件数值均为显著线性正相关关系。(2)随着生境干旱化程度增加,高山嵩草分株数量增加,矮生嵩草分株受干旱抑制程度高,分株数量呈下降趋势;2种嵩草分株功效下降,即单株叶片数量因干旱化程度增加而减少。(3)2种嵩草的茎基直径、叶片萌生能力随着生境干旱化程度增加而下降;高山嵩草叶片萌生能力的变化与生境干旱化梯度一致,具有连续性;矮生嵩草叶片萌生能力对生境干旱化的适应性弱,干旱到一定程度发生骤降。(4)随着生境干旱化,高山嵩草的根系数量和长度均增加,矮生嵩草根系长度增加,但数量却无规律变化;2种嵩草的根系分生功效和根系伸长功效均下降。研究表明:嵩草属植物分布的最适宜生境为表面稍有积水的沼生生境。为适应生境干旱化,高山嵩草降低叶片萌生率以减少蒸腾作用,增加分株数量以增强对空间的占有能力,并增加根系数量和长度来提高对土壤水分的吸收能力,因此对干旱有较强适应性且分布范围广;矮生嵩草只通过降低叶片萌生率,增加根系长度响应干旱化生境,其分布范围较窄。  相似文献   

18.
The role of Hemipteran saliva and salivary enzymes is central to an understanding of the etiology of damage that these insects cause to plants. The dilute nature of the salivary secretions and the minute quantities in which they are often obtainable have made analysis and detection of salivary components very difficult. Such investigations in this laboratory have led us to formalise the techniques involved and we believe that the compilation of these methods presented herein may be useful to other research workers in this area. Methods are described for acid and alkaline phosphatase, esterase, /S-glucosidase, carbohydrases, invertase, amylase, proteinase, pectinase, cellulase, catalase, peroxidase, catechol oxidase, superoxide dismutase and ascorbic oxidase.  相似文献   

19.
民勤绿洲边缘地下水位变化对植物种群生态位的影响   总被引:3,自引:0,他引:3  
在民勤绿洲边缘,利用空间区域不同地下水位(湖区8~12m,泉山区15~17m,坝区20~23m)和时间序列(1984~1992年)民勤沙井子地区地下水位下降(7.45~11.65m)梯度,研究地下水位下降对荒漠植物种群生态位的影响。结果表明:空间区域地下水位下降,植物种群生态位宽度均减小,种群退化;时间序列地下水位下降,白刺种群在扩展,其它植物种群在退化。白刺种群生态位宽度在民勤绿洲边缘荒漠植物群落中最大,是该区的建群种。由于白刺种群在地下水位7.45~11.65m范围内扩展,民勤绿洲生态环境治理中地下水位达到该范围是一个主要目标。  相似文献   

20.
Photoinactivation of Photosystem II (PS II), the light-induced loss of ability to evolve oxygen, inevitably occurs under any light environment in nature, counteracted by repair. Under certain conditions, the extent of photoinactivation of PS II depends on the photon exposure (light dosage, x), rather than the irradiance or duration of illumination per se, thus obeying the law of reciprocity of irradiance and duration of illumination, namely, that equal photon exposure produces an equal effect. If the probability of photoinactivation (p) of PS II is directly proportional to an increment in photon exposure (p = kΔx, where k is the probability per unit photon exposure), it can be deduced that the number of active PS II complexes decreases exponentially as a function of photon exposure: N = Noexp(−kx). Further, since a photon exposure is usually achieved by varying the illumination time (t) at constant irradiance (I), N = Noexp(−kI t), i.e., N decreases exponentially with time, with a rate coefficient of photoinactivation kI, where the product kI is obviously directly proportional to I. Given that N = Noexp(−kx), the quantum yield of photoinactivation of PS II can be defined as −dN/dx = kN, which varies with the number of active PS II complexes remaining. Typically, the quantum yield of photoinactivation of PS II is ca. 0.1μmol PS II per mol photons at low photon exposure when repair is inhibited. That is, when about 107 photons have been received by leaf tissue, one PS II complex is inactivated. Some species such as grapevine have a much lower quantum yield of photoinactivation of PS II, even at a chilling temperature. Examination of the longer-term time course of photoinactivation of PS II in capsicum leaves reveals that the decrease in N deviates from a single-exponential decay when the majority of the PS II complexes are inactivated in the absence of repair. This can be attributed to the formation of strong quenchers in severely-photoinactivated PS II complexes, able to dissipate excitation energy efficiently and to protect the remaining active neighbours against damage by light.  相似文献   

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