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1.
中国荸荠属植物果皮微形态特征及其分类学上的意义   总被引:3,自引:0,他引:3  
报道了国产荸荠属26 种、3 变种植物果皮在扫描电镜下的纹饰特征.结果表明,根据果皮细胞形状和外壁纹饰的差异,可分:(1) 光滑型纹饰:果实表面光滑,无细胞结构;(2) 网状纹饰:在(2) 类型中根据植物果皮垂周壁的结构和细胞形态又可分为两个亚型,即网状纹饰亚型和波形网状纹饰亚型.本属植物果皮微形态特征总体而言较为相近,表明是一个自然类群.果皮纹饰类型及微形态特征在组间或系间相互交叉和渗透,与传统分类中组、系的划分不相对应.此外,本属果皮微形态特征在种下等级的差异较明显,但在种内个体间比较稳定,变异很小.上述研究结果可为国产荸荠属种间区别提供依据.  相似文献   

2.
本文报道了中国-喜马拉雅柴胡属(Bupleurum L.)24种,7变种,2变型的花粉形态研究结果,全部在光学显微镜和扫描电镜下作了比较观察。有关柴胡属花粉形态的研究,除大苞柴胡(B.eupho-rbioides Nakai)和红柴胡(B.scorzonerifolium Willd.)外,其余均为首次报道。根据该属花粉粒的形态和萌发孔特征,其花粉形态可分为三个类型,即:近菱形角孔类型、矩形边孔类  相似文献   

3.
中国-喜马拉雅柴胡属的花粉形态及其系统学意义   总被引:1,自引:0,他引:1  
本文报道了中国-喜马拉雅柴胡属(BupleurumL.)24种,7变种,2变型的花粉形态研究结果,全部在光学显微镜和扫描电镜下作了比较观察。有关柴胡属花粉形态的研究,除大苞柴胡(B.euphorbioidesNakai)和红柴胡(B,scorzonerifoliumWilld.)外.其余均为首次报道,根据该属花粉粒的形态和萌发孔特征,其花粉形态可分为三个类型,即:近菱形角孔类型、矩形边孔类型及其二者之间的过渡类型。花粉形态资料支持德国植物系统学家德鲁特(O,Drude,1898)关于柴胡属的系统位置,将其隶于芹亚科(Apioideae),芹族(Apieae),葛缕子亚族(Carinae)。  相似文献   

4.
对从木麻黄、杨梅、桤木和胡颓子等宿主植物根瘤中获得的19株分离菌的离体培养形态特征、生理特性和交叉侵染特性等进行了比较分析.结果表明,各分离菌均有Frankia属所特有的分枝状菌丝、孢囊、泡囊或串珠状菌丝等形态结构;细胞壁类型多属胞壁Ⅲ型,生理类型多属B型,无氮诱导培养下都具有同氮酶活性,在BAP、JA或S培养液中菌体生长较好,以吐温-80和酪蛋白水解物为最佳碳、氮源.但不同宿主分离菌的形态和培养特征差异明显,木麻黄属分离菌菌丝较粗,孢囊数量较少,在BAP培养液中多旱荔肉白絮状颗粒沉淀;杨梅属菌丝较细,孢囊数量较多,在BAP培养液中多是浅红色颗粒沉淀;桤木属和胡颓子属的菌体形态特征在BAP培养液中与木麻黄属的相似,但桤木属菌丝较细,胡颓子属的菌丝较粗.根据回接及交叉侵染特性可将分离菌分为2个宿主特异类群:能侵染木麻黄苗木的木麻黄类群;只侵染原宿主并能在杨梅属、胡颓子属和桤木属间相互侵染,但不能使木麻黄属苗木结瘤的杨梅-桤木-胡颓子类群.图2表5参19  相似文献   

5.
利用光学显微镜对国产耳蕨属后生耳蕨组和新生耳蕨组31个种40个样品成熟叶表皮的细胞的形态特征的研究结果表明,后生耳蕨组和新生耳蕨组植物的气孔均分布在叶片下表皮,为气孔多形型,气孔基本类型有四细胞型和极型两种;气孔的类型、大小、气孔指数、表皮细胞形状等有一定的稳定性,可以作为后生耳蕨组和新生耳蕨组植物系统与分类研究的依据之一.  相似文献   

6.
青岛东风盐场中极端嗜盐古细菌的特性   总被引:3,自引:0,他引:3  
从青岛东风盐场分离到3株嗜盐古细菌(编号:ZDA-1,ZDA-2和ZDA-5),细胞为多形态杆状(0.7~15μm×2.0~50μm),最适生长NaCl浓度为3.4mol/L,含有甘油二醚脂,类胡萝卜素色素和极性脂TGD-2(三糖基二醚脂),x(C+C)分别为63.7%,62.7%,和64.3%,据此,这3株菌可归入嗜盐小盒苗属(Hchoarcula);但它们不水解淀粉,明胶不液化,不水解酪蛋白等生理生化特性不同于该属中现已正式承认的两个种,因此,本工作分离的3株菌可能是嗜盐小盒菌属一个新种.  相似文献   

7.
基于博格达山北坡68个表土样品花粉组合特征,对比植物群落样方调查结果,借助聚类分析、主成分分析方法,探讨了表土花粉组合与现代植被分布的关系。研究表明,(1)博格达山北坡表土花粉可划归5个不同植被带,湿度是影响其分布的主要因素,藜科(Chenopodiaceae)、蒿属(Artemisia)、云杉属(Picea)花粉分布受气流影响显著,忽略它们对其他植被带花粉组合的干扰,表土花粉与现代植被分布对应良好。各植被带均有其特有的花粉组合方式,山地荒漠带藜科-蒿属组合占绝对优势,山地草原带演替为蒿属-藜科-禾本科(Poaceae)-蔷薇科(Rosaceae)组合,山地森林带以云杉属-桦木属(Betula)-蒿属-藜科-禾本科为主,高山草甸带以蒿属-云杉属-藜科-莎草科(Cyperaceae)组合为特征,高山垫状植被带表现为蒿属-藜科-蔷薇科-云杉属组合。(2)草本植物花粉含量(62.7%)优势明显,乔、灌木(37.3%)次之。蒿属(23.1%)、藜科(21.5%)、云杉属(18.1%)、莎草科(9.4%)、禾本科(8.6%)、桦木属(5.7%)、蔷薇科(5.3%)等科(属)含量高、变幅大,为最主要的花粉类型,可作为古气候研究的重要依据,藜科、蒿属产量大、易传播,表现出超代表性,云杉属代表性较好,莎草科则受自身结构及保存条件等多重因素影响呈低代表性。(3)蒿属/藜科(A/C)比值不仅能将山地荒漠带、山地草原带区分开,还能指示研究区域湿度变化,古环境重建时可作为区域有效湿度的代用指标。  相似文献   

8.
用表型数量分析方法,结合地理分布对川西苹果属11个野生种进行研究,探讨其种间关系与地理分布的联系.得结论如下:1.不同系数的WPGMA和UPGMA聚类结果基本相同.表型数量骤类分析能大体反映近缘种间的亲缘关系;2.滇池海棠与沧江海棠在形态上高度相似,聚类图上极靠近,分布上相重叠,在塑定上有时感到困难;3.花叶海棠与变叶海棠和稻城海棠与小金海棠,从表型及分布上看显然是地理替代种;4.本文所列各种,大都分属两大植物区系范围内,例如花叶海棠属中国-日本区东范围内,变叶海棠属中国-喜马拉雅区系范围内;5.发现沿康定-理塘-巴塘(约(N)30°)存在一条南北物种分布的分界地带线,称康-巴线;沿岷江上游和大渡河流域也存在一条明显的地带线,称岷江-大渡河带,这一带就是中国-喜马拉雅区系和中国-日本区系的交界地带,通过这一地带有些向南分布的种可以越过康-巴线以东地区到达金沙江边,向北分布的种有时也可越过康-巴线以东达到岷江上游。在这南北和东西交界带上,不同物种会集,无疑是物种分化以及种质渗入十分活跃的地带;6.与其它地区相比较,四川西部山区是我国野生苹果植物分化的多样中心。  相似文献   

9.
结缕草Zoysia japonica克隆植株的基本形态学单元是复合节间。分析复合节间组分关系,可以进一步揭示其形态可塑性的细微特征和资源传输与分配的差异,同时也可以为形态可塑性成因提供合理的生理生态学解释。本文对温室内、外两种环境条件下生长的结缕草克隆植株的复合节间组分进行测定和分析,结果表明:温室内、外植株主匍匐茎的长度和生物量的波动比一级分枝大,缩短节间长度比伸长节间长度稳定,但缩短节间生物量较伸长节间生物量变化幅度大。伸长、缩短节间长度、生物量分别与复合节序数呈二次函数关系。伸长、缩短节间生物量和分株生物量在一个生长季的生长方程亦均呈二次函数关系。主匍匐茎根数量、生物量随复合节数递增基本呈递增趋势。在两种环境下,A分株根数、生物量均大于B分株根数、生物量(在结缕草匍匐茎上,着生于每个复合节的基端和梢端缩短节间上的分株分别称为A、B分株),且差异明显。温室内植株,在分株发育形成后,伸长、缩短节间的长度、生物量分别与匍匐茎根、A分株根数、B分株根数、生物量间相关性显著,温室外的相关性格局较复杂,且总体显著性低于温室内。结缕草克隆植株基本形态结构单元的复合节上的各个组成部分之间存在的密切相关关系,是导致结缕草克隆植物形成形态可塑性的细微特征格局的主要原因。  相似文献   

10.
水体中氧化铁鞘细菌的分离鉴定及保藏   总被引:5,自引:1,他引:5  
采用试管静止富集培养及生态模拟富集培养,结合平板划线、稀释涂布、平板滴加法,成功地从150份水样中分离到94株鞘细菌.利用Winogradsky液体试管法进行产铁氧化酶鞘细菌的快速初筛,从中筛选出24株产铁氧化酶能力较高的菌株,再经摇瓶复筛,获得产酶活性最高的菌株FC9901.采用多相鉴定方法对菌株FC9901细胞形态、培养特征、生理生化反应及各种碳源利用情况进行了研究,根据《伯杰氏细菌鉴定手册》第9版,把该菌株鉴定为第十四群鞘细菌类(sheathed bacteria)球衣菌属(Sphaerotilus)浮游球衣菌(Sphaerotilus natans).对鞘细菌几种保藏方法进行比较研究,结果表明蒸馏水保藏法保藏时间长,是一种经济简便有效的保藏方法.图3表7参9  相似文献   

11.
In evolutionary biology, whether parents should enhance or reduce parental care according to mate ornamentation is a subject of great debate. However, the evolution of female ornaments can shed light on this question. In theory, female ornamentation should be traded off against fecundity and thus cannot be wholly informative to males without a direct indication of fecundity. Hence, direct cues of offspring quality should affect the relationship between male investment and female ornamentation. Under this hypothesis, we manipulated two direct cues of offspring quality (egg size and color) after first egg laying in the blue-footed booby and registered male incubation patterns. In this species, foot color is a dynamic signal of current condition and in females is traded off with egg size. We found that males spent more time incubating when paired with dull females but only in nests with large eggs. Males also spent less time incubating small dull eggs. Results indicate that egg size, a direct cue of reproductive value, affected the relationship between male effort and female ornamentation. Males may be willing to help females that have invested in offspring at the expense of ornamentation, which suggests compensation when females are in low condition. Another possibility is that males relax their effort when paired with highly ornamented and fecund females because they have high parenting abilities. Our findings suggest that the information conveyed by female ornaments may depend on direct cues of fecundity. Results also highlight that parental decisions are complex, modulated by a combination of information sources.  相似文献   

12.
One strategy for predator avoidance involves the creation of a structural refuge. Onuphid polychaetes characteristically ornament above-sediment portions of their tubes (=tube-caps) with shell and algal debris. These species feed on the sediment surface through an opening in the tube-cap, and thus the ability to detect a surface predator while feeding would be advantageous. An investigation of the function of the ornamentation in Diopatra spp. suggests that ornamentation facilitates predator detection and avoidance. Three intensities of mechanical disturbance were applied directly to D. ornata tube-caps. When ornamented tube-caps were stimulated, the response of worms to the three intensities were significantly different, and increased in duration with greater intensities. In contrast, when no ornamentation was present, the responses were not significantly different, and were similar to the low-intensity response when ornamentation was present. This suggests that ornamentation should allow a worm to distinguish between harmful (high intensity due to mobile epifaunal predators) and profitable (low intensity due to drift algae) disturbances, and furthermore, worms with ornamented tube-caps should be more successful in escaping surface predators. Densities of intertidal populations of D. cuprea at Tom's Cove, Virginia, USA, correlated with the amount of tube ornamentation, consistent with this predator detection and avoidance hypothesis. Final tube-cap lengths of laboratory D. ornata and field D. cuprea were inversely related to the size of attached debris. When large debris was attached, cap formation ceased earlier and caps were shorter than when small debris or no debris was attached. Cryptic and food-catching functions would predict that highly ornamented tubes would be most advantageous, while only a few large debris would be required for disturbance transmission. Laboratory specimens showed no selectivity between 0.5 or 1.5 cm2 shell; or 1.0 cm2 or 3 to 8 cm2 algae, and utilized shell and algae when available and according to relative abundance. Tube-caps of field specimens also showed positive correlations between shell attached and shell abundance in the local sediment. While such lack of selectivity may enhance cryptic properties of the tube-cap, it is argued that conditions seldom exist which would permit selectivity of debris size or of specific material. These data are consistent with the hypothesis that ornamentation functions as a created refuge for predator detection and avoidance and further suggest that the availability of ornamental debris in the environment indirectly can affect these species' distributions and abundances.  相似文献   

13.
We used guppies to study repeatability in sperm competitiveness and postcopulatory sexual selection on male ornamentation. In a block design involving 25 pairs of males, artificial insemination was used to mate each pair (A and B) to four unrelated females—two that were mated with the combined ejaculates of both males (sperm-competition treatment) and two receiving sperm from each of the two males individually (single-male treatment). Our analysis revealed significantly repeatable patterns of paternity across females in the sperm-competition treatment, suggesting that certain males are intrinsically better sperm competitors than others, irrespective of female identity. Next, we compared mean brood success (number of offspring per brood) between sperm competition and single-male treatments. We found no significant effect of treatment on female fecundity, suggesting that the previously reported direct benefits of polyandry in this species may be due to factors such as differential maternal effects or differences in the number of inseminated sperm between treatments. Our artificial insemination assay was designed to control both factors. Finally, we determined whether variation in relative paternity was random with respect to male phenotype. Unlike previous work on Trinidadian populations, we found no significant relationship between male sexual ornamentation and sperm competitiveness in the focal population.  相似文献   

14.
This study used both correlative and experimental video playback methods to test the hypothesis that the secondary sexual traits of male wolf spiders act to increase the efficacy of visual courtship displays. Direct observations of courtship of several lycosid genera and a review of the literature revealed a significant association between ornamentation and visual courtship displays. This suggests that the ornamentation may be playing the role of amplifier for a visual display. To test this hypothesis, male courtship behaviors of four Schizocosa species were experimentally manipulated using video-imaging techniques. Females of species with non-visually displaying, non-ornamented males (Schizocosa duplex and S. uetzi) did not increase in frequency of receptivity when tufts were added to conspecific males. In a species with a visual display and foreleg pigmentation (S. stridulans), the addition of foreleg tufts increased female receptivity. In a tufted species (S. crassipes), females tended to decrease their receptivity when male ornamentation was completely removed. In visually displaying species, ornamentation acts to increase female receptivity, supporting its role as an amplifier of a visual display. Received: 29 December 1997 / Received in revised form: 23 October 1999 / Accepted: 13 December 1999  相似文献   

15.
Schizocosa wolf spiders show tremendous diversity in courtship complexity, with different species employing varying numbers of components within and across sensory modalities. Using a comparative approach, we investigate the importance of each signaling modality in the courtship display of five Schizocosa species (three stridulating and two drumming) by assessing mating success under manipulated signaling environments. Irrespective of the degree of male ornamentation, the three stridulating species exhibit a dependence on the seismic, but not visual, signaling environment for mating success. Mating was independent of signaling environment for the two drumming species. We next ask whether the degree to which each species depends upon a signaling modality for mating (i.e., modality importance) is correlated with the estimated modality-specific signal complexity. We first calculate effect sizes for the influence of seismic versus visual signaling environments on the likelihood to mate for ten Schizocosa species and then use an element-counting approach to calculate seismic and visual signal complexity scores. We use a phylogenetic regression analysis to test two predictions: (1) the importance of seismic signaling is correlated with seismic signal complexity and (2) the importance of visual signaling is correlated with visual signal complexity. We find a significant relationship between visual signal importance and visual signal complexity, but no relationship between seismic signal importance and seismic signal complexity. Finally, we test the hypothesis that selection acts on complexity per se by determining whether seismic and visual signal complexity is correlated across species. We find support for this hypothesis in a significant relationship between seismic and visual signal complexity.  相似文献   

16.
A fundamental way in which animal-dispersed plants can influence the viability and distribution of dispersed seeds is through control of retention time in the guts of dispersers. Using two species of wild chilies and their dispersers, we examined how chemical and physical properties of fruits and seeds mediate this interaction. Capsicum chacoense is polymorphic for pungency, occurs in Bolivia, and is dispersed mostly by elaenias. Capsicum annuum is not polymorphic, occurs in Arizona (USA), and is dispersed mostly by thrashers. We first tested whether capsaicin, the substance responsible for the pungency of chilies, affects gut retention time of seeds in primary dispersers. Capsaicin slowed gut passage of seeds but did so in a manner that differed greatly between bird species because the constipative effects of capsaicin occurred only after an 80-minute time lag. Elaenias in Bolivia held only 6% of C. chacoense seeds for > 80 minutes, whereas thrashers in Arizona held 78% of C. annuum seeds for > 80 minutes. Next we examined the effects of retention time on seed viability and germination. Increased retention resulted in a greater proportion of seeds germinating in C. annuum, had no effects on non-pungent C. chacoense, and had negative effects on pungent C. chacoense. These divergent effects are explained by differences in seed coat morphology: seed coats of pungent C. chacoense are 10-12% thinner than those of the other two types of seeds. Thus, longer retention times damaged seeds with the thinnest seed coats. In C. annuum, seed viability remained high regardless of retention time, but germination increased with retention, suggesting a role for scarification. Thus, in C. annuum, fruit chemistry appears well matched with seed morphology and disperser physiology: capsaicin extends gut retention for most seeds, resulting in greater seed scarification and higher germination rates. Increased retention of pungent C. chacoense seeds is detrimental, but because the primary consumers have short retention times, capsaicin slows only a small proportion of seeds, minimizing negative effects. These results illustrate the importance of context in studies of fruit secondary metabolites. The same chemical can have different impacts on plant fitness depending on its morphological, physiological, and ecological context.  相似文献   

17.
The effectiveness of a frugivore as a disperser of a plant is greatly determined by how fruits and seeds are handled in its mouth and its digestive tract. Although a number of studies have investigated the effect of avian ingestion on germination, we still know very little about the modifications to seeds during ingestion and the specific consequences on plant fitness. Here we investigate for the first time the different mechanisms by which germination patterns of seeds are modified following ingestion by frugivores. Specifically, we examine changes in seed mass, water content, permeability, seed coat thickness, texture, and resistance in two common Mediterranean fleshy-fruited plants, Phillyrea angustifolia and Myrtus communis, after ingestion by Eurasian Blackbirds, Turdus merula. We found a number of differences between the plant species: Phillyrea seeds lost mass, mainly due to water loss, and had thinner coats after gut passage, but Myrtus seeds did not. Seeds of both species showed increased permeability, while Myrtus seeds in particular became less resistant to breakage. No quantifiable changes in seed coat texture were detected in either species, although this trait was partly associated with differences in germination rate in Phillyrea. High intraspecific plant variation was found for most seed traits measured. Seed passage through birds' guts sped up germination in both species, especially in Myrtus. Increased permeability in seeds of both species following ingestion resulted in a higher germination rate. Moreover, seeds with thick coats (and in the case of Phillyrea, harder coats) germinated at a slower rate and produced seedlings that also grew more slowly, indicating a cost of coat thickness and/or hardness for seedling emergence. Results obtained here contribute to explaining the great heterogeneity in germination responses among and within plant species and the large variety of factors, both intrinsic and extrinsic to the plants, that influence such responses.  相似文献   

18.
The Hamilton–Zuk hypothesis proposes that females prefer male secondary sexual traits because they are honest indicators of parasite resistance. Despite the attention that this hypothesis has received, its role in sexual selection remains equivocal. This study presents the first field test in guppies of two key predictions of the Hamilton–Zuk hypothesis: (1) that within populations, the most highly ornamented males have the fewest parasites and (2) that among populations, males in high parasite populations have the most conspicuous ornaments. Five hundred male guppies from 19 distinct populations in the Northern Range of Trinidad were inspected for Gyrodactylus parasites and photographed. Eight measures of orange spot ornamentation were used to test the predictions: hue, saturation, lightness, relative area, number, and area-weighted hue, saturation, and lightness. Parasite load had no significant effect on any of these measures. There was also no relationship between orange spot ornamentation and parasite abundance among populations. Guppies from high-predation environments had significantly more parasites, and their orange coloration was lighter and less saturated than that in guppies from low-predation environments. Despite previous lab results, this study found no relationship between parasite load and male orange spot ornamentation.  相似文献   

19.
Ornamentation predicts reproductive success in female pipefish   总被引:5,自引:0,他引:5  
In the sex-role reversed pipefish Syngnathus typhle females compete for access to males and males are choosy. Females develop a temporary ornament when competing over mates with other females and when performing nuptial dances with males. This ornament is an amplification of the normal striped pattern in these fishes. We here show experimentally that (1) the contrast of this normal pattern forecasts the extent to which the ornament is shown, (2) contrast and ornamentation honestly signal female quality (egg numbers), (3) contrast and ornamentation accurately predict female mating success, (4) contrast is a phenotypically plastic trait specifically exaggerated under situations of female – female competition, and (5) neither contrast nor ornament are energetically expensive to the females (i.e., they are independent of short-term nutritional status). Hence, as predicted in sex-role reversed species, ornament design is constrained by costs to female fecundity: an energetically demanding ornament would impair on a female's ability to produce eggs. The type of ornament described here is the expected one, costly for reasons other than being energetically expensive to produce. Received: 4 April 1996 / Accepted after revision: 27 October 1996  相似文献   

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