Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

1947 ◽  
Vol 45 (4) ◽  
pp. 413-416 ◽  
Author(s):  
E. M. Brieger ◽  
C. F. Robinow

In a cytological investigation of three branching and two non-branching strains grown on Loewenstein medium, it was found that avian tubercle bacilli contain chromatinic material which gives a positive Feulgen reaction and is readily stainable with Giemsa's solution after treatment of the fixed bacteria with hydrochloric acid.Growing filamentous forms of both ‘bacterial’ and ‘mycelial’ strains from 1 to 2 day old cultures contain variable numbers of irregularly spaced, more or less spherical chromatinic bodies which vary in staining in the same bacillus, some being red, others purple. During the third or fourth day the chromatinic material in the bacteria increases very much until most of it is fused into an almost homogeneous deeply stained column. In thenon-branchingstrains the filamentous forms with high chromatin content soon break up into small mono-or binucleate elements, and the same holds true for the ‘straight’ filamentous forms which are also present in cultures of branching strains. The ‘mycelial’ forms, on the other hand, disintegrate at this time (fourth or fifth day of cultivation), and it is uncertain whether they contribute (by partial fragmentation) to the masses of small mono- or binucleate forms which are the predominant element in old cultures of all the strains investigated.The chromatinic structures of avian tubercle bacilli have the same staining properties as those of ordinary non-acid-fast bacteria but differ from them in their behaviour during the early development of the bacilli.


Author(s):  
Joseph P. Vincenzo

In Vico’s New Science wisdom is understood in a double sense. On the one hand, wisdom means the poetic wisdom that provides intelligibility for the peoples of the nations during their early stages of development. On the other hand, wisdom means the noetic knowledge gained by the Vichian scientist who contemplates concrete historicity in the light of the New Science. By means of an examination of three principle aspects of Vico’s science, and by looking to his conception of the origin of the most rudimentary institutions of humanity, primordial piety— fear of the mythic other— is shown to be the origin of poetic wisdom. And, by focusing on the necessity of surmounting the conceit of scholars and the conceit of nations for a science of universal history, philosophical piety— openness to the wholly Other— is revealed as the ground of philosophical wisdom. This paper sets out to show how Vico’s science of the principles of humanity is, at the same time, a science of the unity of piety and wisdom.


1878 ◽  
Vol 169 ◽  
pp. 505-521 ◽  

The following paper contains an account of observations on the development of the species Cymothoa œstroides and C . parallela of Milne Edwards; but the forms of the young seem to show that several species are really included under these two names. In the early stages of development the only observable difference that exists between the embryos is one of size, but in the later stages they differ very markedly from each other in their external characters. From adult individuals answering the description of C . œstroides I have obtained four varieties of embryos: two with long antennae and two with short.* In the two former the first pair of antennae are but slightly longer than the head, while the second pair are longer than the body; the eyes are small. In one of the varieties thus characterised the abdominal appendages are fringed with long hairs (fig. 20), and in the other they are smooth.


1906 ◽  
Vol 12 ◽  
pp. 318-330
Author(s):  
R. M. Dawkins

The archaic remains, which the trial trenches have revealed at a level beneath the Roman building and temple described above, present in one respect a striking contrast. Except inscriptions, the later buildings have not yielded many small objects: their importance lies in their architectural arrangement and purpose. In the archaic stratum on the other hand, although some architectural fragments have already been found, and more are expected, the chief interest centres in the wonderful wealth of small objects, doubtless votive offerings, and the light they throw on the early stages of art in Sparta. Before our work this year, this deposit was accessible only from the side of the river, where erosion has produced a section of all the strata from the present surface down to virgin soil. This face, shewn in Fig. 1, p. 319, in its original condition before excavation, we have protected with a wall, to guard the site from the destructive effect of the floods to which the Eurotas is liable, the lowest remains being hardly higher than the level of the bed of the river. Work was begun at this naturally exposed face, where the lead figurines now in the Sparta Museum were found, which gave the first clue to the site, and the number of archaic objects unearthed in the first few hours immediately revealed its extraordinary richness.


1967 ◽  
Vol 20 (2) ◽  
pp. 465 ◽  
Author(s):  
PJ Hardy

Sucrose is the major translocated sugar in the grapevine (Swanson and EIShishiny 1958), but in the berry glucose and fructose together make up the bulk of the sugar content at all stages of development (Kliewer 1965a). The inversion of sucrose to glucose and fructose in ripening berries is suggested by the presence of invertase (Arnold 1965) and by the occurrence of approximately equal amounts of glucose and fructose (Kliewer 1965a). During the early stages of berry development, glucose and fructose concentrations are low, but at the onset of ripening there begins a phase of rapid glucose and fructose accumulation (Kliewer 1965a). Besides sugar, the other major soluble constituents of grapes are malate and tartrate. The concentrations of both substances increase rapidly in the immature berry, but when ripening commences sharp decreases occur, particularly in the concentration of malate (Kliewer 1965b). Some workers believe that malate and tartrate are translocated from the leaves (Amerine 1956; Peynaud and Maurie 1958) but there is evidence that some at least of the malate and tartrate is synthesized in the berry (Hale 1962). The mechanisms of the syntheses of malate and tartrate in the berry are not known.


Author(s):  
Т.К. САЛБИЕВ

В статье предлагается добавить к двум традиционно выделяемым этапам истори- ческого развития Нартиады еще один третий, предполагая, что наряду с родоплеменным и военно-демократическим в своей эволюции она проходит еще и через феодальный этап. С общефольклорной точки зрения они будут соответствовать трем следующим фазам: разрозненные сказания; циклы, образуемые вокруг главных героев; гиперциклизация / це- лостная эпопея. В результате получают иную интерпретацию не только сюжеты и мо- тивы эпопеи, представленные в ней персонажи, но и ее общее содержание, а также в ином свете предстает ее прагматика, то есть место и роль в традиционной культуре в целом. Основой для пересмотра общепринятой точки зрения является пока еще в полной мере не оцененное сообщение «Хронографа» (груз. «Жамтаагмцерели») – «Столетней летопи- си» XIV в. Содержащееся в памятнике отождествление аланской правящей династии с эпическим воинским родом Ахсартаггата позволяет рассматривать Нартиаду как своего рода «Книгу царей». Эпической фигурой, совместившей в своем образе мифологического и исторического царя, следует считать нарта Челахсартага. С одной стороны в его имени распознается связь с родоначальником воинского рода Ахсартага, представляющего мифо- логическую эпоху. С другой стороны, он носит титул исторического средневекового прави- теля Ас-Тархана. Благодаря имени его дочери (Бедуха), которое может рассматриваться как просторечный вариант имени Бурдухан, он может быть отождествлен с аланским царем XII в. Худданом. Сама эпопея в этом случае могла бы рассматриваться как средство легитимизации аланской правящей, то есть исторической, династии на власть. Участие царской династии в событиях эпопеи обеспечивало ей преемственную связь с мифологи- ческой эпохой, что и давало ей необходимое идеологическое обоснование господствующего положения в обществе. The article advances a proposition to add a third feudal stage to the two traditionally distinguished stages of the historical development of the Narts’ epic, suggesting that alongside with the tribal and military-democratic stages of its evolution it goes through the feudal one as well. From a point of view of general folklore, these will correspond to the following three phases: scattered legends – cycles formed around the main characters – hypercyclization / complete epics. As a result, not only the plots and motifs of the epic, the characters represented in it, but also its general content are reconsidered, its pragmatics, i. e., its place and role in traditional culture as a whole are seen in a different light. The basis for the review of the generally accepted theory is a passage from the so-called “Chronograph” (Georgian “Zhamtaagmcereli”), or the “Hundred Year Anniversary” of the XIV century. The identification of the Alanian ruling dynasty with the epic military lineage of Axsærtæggatæ the mentioned work contains makes it possible to consider the Nart epic as a kind of “Book of Kings”. From this point of view, Nart Čelæxsærtæg should be regarded as a hero, in whose image the traits of mythological and historical kin are interwoven. On the one hand, his name recognizes the link with the ancestor of the military family Axsærtæg, representing the mythological era. On the other hand, he holds the title of the historical medieval ruler As-Tarxan. Thanks to the name of his daughter (Bedukha), which can be considered as a vernacular version of the name Burdukhan, he can be identified as Khuddan, the Alanian king of the XIIth c. In this case, the epic itself could be considered as a means of legitimizing the Alan ruling, that is, historical dynasty of power, which thus provided its continuity with the mythological epoch, giving it the necessary ideological basis for the dominant position in the society.


1926 ◽  
Vol 22 (10) ◽  
pp. 1185-1185
Author(s):  
V. Gruzdev

It is well known that this operation has recently become extremely widespread in obstetric practice. It is used to empty the uterus not only in term births, but also in the early stages of pregnancy. The negligible primary mortality after this operation in the hands of modern obstetricians partly justifies its enthusiasm; on the other hand, however, it should not be forgotten that it sometimes creates such changes in the uterus that threaten serious danger in subsequent pregnancy.


Author(s):  
Michael Pondělíček ◽  
Vladimíra Šilhánková

Villages and their functions in the landscape have changed significantly, and the 21st century has brought with it a number of problems in the functioning of village settlements and the rural landscape. The aim of the paper is to analyze the role of the current village in the landscape and biodiversity in the landscape and to outline the possibilities of its functioning in this system and its further development. The work is processed mainly by means of the method of terrain and local surveys. The analysis shows that throughout the 20th century the possibilities of animal and plant move in the landscape decreased and diversity in the form of gardens, cemeteries, parks and other green formations was concentrated in settlements and their immediate vicinity. Contemporary villages and smaller towns have already had a relatively stabilized strip of greenery around them, which was created together with ensuring a quality environment (e.g., soundproofing or sun elimination). This, on the other hand, allowed animals that had not been common in settlements to move into villages. To our surprise, the villages become a treasure trove of biodiversity and the preservation of fragments of important habitats from previous stages of development. The care of intra-settlement greenery thus faces a new, as yet unknown, task - how to maintain and further develop this newly created biodiversity.


1974 ◽  
Vol 52 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Ruth Perassi ◽  
José A. Cerisola

The antigenic composition of haemolymph from some reduviids was studied by means of immunochemical methods.No differences were detected between haemolymph from Triatoma infestans and Triatoma platensis. On the other hand, important qualitative and quantitative differences were observed in the antigenic composition of the haemolymph from Triatoma phyllosoma pallidipenis, Triatoma spinolai, Triatoma rubrovaria, Triatoma vitticeps, Rhodnius prolixus, and Rhodnius neglectus with respect to Triatoma infestans.


Sign in / Sign up

Export Citation Format

Share Document