Mode Of Branching Research Articles

Response of Kientzler New Guinea Impatiens to Manual and Chemical Pinching

Manually and chemically pinched plants of 18 cultivars of Impatiens hybrids (Kientzler New Guinea impatiens) were compared to control plants to determine the effect of shoot apex removal on flowering, plant size, and branching characteristics. Either pinching treatment delayed flowering by ≈3 days compared with nonpinched controls. Pinching had no effect on plant height or fresh or dry weight. Plant diameter and form changes due to pinching depended on cultivar. Total branch count was increased by chemical but not manual pinching although both pinching methods affected mode of branching. The 18 cultivars of Kientzler New Guinea impatiens were best grown as 0.4-liter potted plants without the aid of pinching.

A correction model for the incompatible deformations of the shear internal crack

The exact solution for the internal crack in an elastic plate submitted to a pure shear loading at infinity stipulates that an in-plane and out-of-plane overlapping of the crack flanks always happens, which invalidates the solution. A model is developed in this paper based on the compatibility conditions for the displacements along the crack flanks, which approximate in a physically reasonable way the stresses and displacements created along the flanks of the sheared crack and which enable a rational approach to the solution of this basic problem. Using the elastic solution derived from this model, an explanation of the mode of propagation and branching of an elastic crack was forwarded.

Notes on the Neckeraceae (Musci) 8.Pendulothecium, a new genus from New Zealand and Norfolk Island

Abstract Pendulothecium Enroth & He gen. nov. (Neckeraceae) includes the species P. oblongifolium (Hook. f. & Wils.) Enroth & He comb. nov., P. auriculatum (Wils.) Enroth & He comb. nov., and P. punctatum (Hook. f. & Wils.) Enroth & He comb. nov. The first mentioned species has previously been assigned to the genus Porotrichum (Brid.) Hampe and the two latter species to Homalia (Brid.) B.S.G., which is pointed out to be almost exclusively a northern hemisphere genus. Pendulothecium is characterised by a unique combination of features, the most important of which are: the (bi)pinnate, often fairly dense mode of branching; the auriculate, mostly not complanate or spreading leaves; the non-twisted, in wet state 150-170 (-250) μm thick setae; and the cemuous to pendulous, in wet state broad-oblong to ellipsoid capsules. An exclusively Australasian (New Zealand and Norfolk Island) distribution provides further generic distinction. All three species are described and illustrated, and a key to them is provided.

On some cladophoraceae (chlorophyta) with long unbranched filaments

Summary Observations on the type material of Conferva obtusangula Lyngbye , Conferva juergensii Mertens in Jurgens , Rhizoclonium pachydermum Kjellman f. pachydermum and Rhizoclonium pachydermum Kjellman f. tenue Kjellman are reported on. Conferva juergensii , established in the printed material accompanying an exsiccata, is typified by one set of this exsiccata. The two Rhizoclonium forms are shown to be based on freshwater material, and a more recent collection of that first mentioned is described in detail. A plant previously referred to Rhizoclonium profundum Brand is found to belong in Cladophora . A Cladophora with an unusual mode of branching is described as Cladophora okamurae ( Ueda ) Van den Hoek f. adnata f. nov. The term merocytic is proposed for an outgrowth that constitutes only part of a single cell.

Verteilung und Tiefenzonierung von schalenbohrenden Endolithen in rezenten Riff- und Schelfbereichen: Cozumel, Yucatán (Mexiko)

Pelecypod shells from bottom sediments of the shelf and upper slope off Cozumel (Mexico), at depths ranging from 1 to 47 m, were studied with regard to the taxonomy, frequency and distribution of microborings produced by endolithic organisms. Scanning electron microscopy of plastic casts of the borings reveals the existence of 29 microboring types, distinguished on the base of shape, size, mode of branching, overall boring pattern and sporangia. The endoliths include cyanobacteria, chlorophycean algae, rhodophycean algae, fungi, sponges and several microborers of uncertain taxonomic affinities. Although most of the borings exhibit a wide bathymetrical range, a subdivision of the photic zone is indicated by the abundance and vertical distribution of some species. The upper part of the photic zone (1–30 m) is characterized by higher species diversity, by the green algaePhaeophila engleri andEntocladia testarum, and by the abundance of the cyanobacteriaHyella gigas. Fungi occur at all depths but are more common in the lower photic zone (30–47 m). The bathymetrical position of the boundary might be influenced by the vertical sampling distance. Generally, there is a good agreement with other bathymetrical patterns of recent endoliths, especially with those from the Puerto Rican carbonate shelf. There is no distinct difference in the frequency or taxonomic composition of shell-boring endoliths from reefs and interreef areas (platforms covered by bioclastic sands). Boring intensity, measured by point-counting of SEM photographs, is generally high; in 58% of the samples 60 to 99% of the outer shell surface is bored, predominantly by fungi and by the green algaPhaeophila engleri. Mean boring intensities show no relationship with water depths.

Sciadiocrinus, convergence on the family Pirasocrinidae (Crinoidea: Echinodermata)

Sciadiocrinus Moore and Plummer is synonymized with Schistocrinus Moore and Plummer, with the name Sciadiocrinus retained by the Law of Priority. This synonymy is based on a reexamination of the type material, study of a previously undescribed ontogenetic sequence in S. tegillum Strimple and Moore, and close inspection of separate radial plates and anal-sac spines. The holotype specimen of the type species of Sciadiocrinus was incorrectly illustrated in the original description of the genus, and appears to be immature. The basal plates of this specimen are shown to be separated from each other by the junction of the radial plates with the infrabasals—a principal character in the original concept of Schistocrinus. The Sciadiocrinus tegillum hypodigm now includes specimens which also have relatively large radial–infrabasal sutures as well as individuals with little or no contact between these plates. Examination of this collection and previously described material shows that mode of arm branching, details of radial-plate articular facets, and some features of the anal-sac spines are also equivalent in the two genera.Sciadiocrinus, presently classified in the family Pirasocrinidae, is distinct from all known pirasocrinid taxa in a number of morphological characters. We believe the genus should be removed from the Pirasocrinidae, and recommend its assignment to the family Anobasicrinidae based primarily on similarities in arm structure. The remarkable convergence between Sciadiocrinus and the Pirasocrinidae emphasizes the adaptive significance of the spinose, umbrella-like anal-sac roof, which apparently served as a deterrent to predators.

A new zosterophyll from the Lower Denovian (Siegenian) of Yunnan, China

A new genus and species, Discalis longistipa, is described from the Posongchong Formation (Siegenian), Wenshan district of Yunnan, China. The plant has creeping axes with numerous K- or H-shaped branches. Aerial branches are either trailing, or upwardly growing, dividing sterile axes with circinately coiled tips and fertile axes with laterally born, disc-like round sporangia. The rather large sporangia, about 3.7 mm in diameter with rather long stalks (up to 5 mm), are sparsely or somewhat compactly scattered along the fertile axes, sometimes spirally, forming loose spikes. It is noteworthy that variable spines with expanded oblate apices, which possibly relate to glands, occur irregularly on the plant, along the stalks, and on the sporangium walls. Discalis longistipa is superficially similar to the genus Sawdonia, but it differs from the latter in the arrangement of its sporangia, the long sporangial stalks and the mode of branching. The discovery of this new plant contributes to our knowledge of early vascular plants. It is of interest to recognize the diversity of them and to speculate about the origins of the microphyll and sporophyll.

A cytoarchitectonic atlas of the medial geniculate body of the opossum, Didelphys virginiana, with a comment on the posterior intralaminar nuclei of the thalamus

The organization of the medial geniculate body and adjacent posterior thalamus of the Virginia opossum was studied in Nissl-, Golgi-, reduced silver, and myelin-stained preparations. Our chief goals were to define the cytoarchitectonic subdivisions and boundaries in Nissl preparations and to reconcile these with those observed with the Golgi method and in experimental material, to present these results in an atlas of Nissl-stained sections, and to compare the chief nuclear groups in the opossum and the cat medial geniculate body. In the opossum, the ventral division consists chiefly of the ventral nucleus. The ventral nucleus is divided into two main parts: the pars lateralis and the pars ovoidea, the former being relatively smaller in the opossum. The ventral nucleus of both species contains large principal neurons with bushy, tufted dendrites and smaller Golgi type II cells. However, the opossum has far fewer Golgi type II cells, and the texture of the neuropil is correspondingly different, although the primary ascending input from the midbrain arises from the central nucleus of the inferior colliculus in both species. The dorsal division consists of the dorsal nuclei, including the suprageniculate nucleus and the caudal part of the lateral posterior nucleus, the marginal zone, and the posterior limitans nucleus. These nuclei are identified in both species, although they are much smaller in the opossum. The neurons consist of medium-size and small somata with a predominantly radiate mode of dendritic branching and a lower cell concentration than in the ventral division. In both species the afferent brain stem input comes from the inferior colliculus, the lateral tegmental area, the intercollicular tegmentum, and the superior colliculus. The medial division contains several types of cells, which are heterogeneous in form and size, most having radiating dendrites and a low cellular concentration. This division is especially smaller in the opossum, although comparable inputs arise from various auditory and non-auditory sources in the midbrain and spinal cord in both species. A large intralaminar complex of nuclei occurs in the opossum, which have a more extensive distribution than previously appreciated. They not only occupy the intramedullary laminae but form a shell around the medial geniculate nuclei and adjoining main sensory nuclei. The intralaminar complex includes the posterior limitans, posterior intralaminar, posterior, parafascicular, posterior parafascicular, central intralaminar, limitans, and central medial nuclei, and the marginal zone of the medial geniculate body.(ABSTRACT TRUNCATED AT 400 WORDS)

The vegetative structure of Medullosa endocentrica (Pteridospermopsida)

A large suite of distinctive medullosan stems with attached branches, lateral buds, and leaves has been discovered in Upper Pennsylvanian sediments of the Appalachian basin. The specimens provide an opportunity to augment our knowledge of the vegetative structure of Medullosa endocentrica Baxter and to significantly expand the concept of the species. Stems are up to 2.3 cm in diameter and bear forking fronds with axillary branches or buds. This represents the first evidence for the mode of branching in medullosan pteridosperms. The stems have two vascular segments, each of which contains a sympodium of the eustele. Phyllotaxis approaches a 3/8 helix, and traces to each leaf diverge in a distinctive pattern over a distance of two internodes. Distal to the basal fork the fronds divide pinnately and bear pinnules that are most similar to Eusphenopteris. The uniformly slender stems, long internodes, consistent absence of attached adventitious roots, and delayed development of appendages below the stem apex provide evidence that M. endocentrica was a liana.

Crack propagation and branching in burning solid propellants

The processes of crack propagation and branching in burning solid propellants are not as yet well understood. These processes could be vitally instrumental in creating large specific-surface areas for burning, and could cause rocket motor failure. Propellant samples have been recovered from interrupted-burning experiments. Different modes of crack propagation and/or branching were observed. Depending upon the rate of pressurization, these modes are: unidirectional crack propagation; single-crack propagation accompanied by branching from various locations; and multiple branching in various directions from the initial crack-tip region. The crack-propagation problem is analyzed through the use of basic physical principles, experimental results, and Schapery's theory of crack propagation. A set of governing dimensionless parameters which control and characterize the degree of damage has been obtained. The controlling dimensionless parameter has been found to depend strongly upon the igniter strength, the chamber pressurization rate, and the fracture energy of the propellant. This set of parameters can be used to develop guidelines for safe operating conditions of rocket motors.

The Ochreole of Equisetum: A Prophyllar Sheath

The genus Equisetum is unique in its mode of branching. The branches are borne at the nodes, but they develop exogenously from the top of the nodal ring, alternating with the sheath segments or leaves. The branch buds develop between leaves rather than being axillary to the leaf, which is the arrangement found in seed plants, or with no relation to the leaves, as in ferns. It is obvious that the branches are associated with the node below them, rather than the nQde above, because if the number of leaves at a node changes, the number of branches is the same as the number of leaves below it. Although exogenous in origin, the branch bud is enclosed by the leaf sheath and must grow out through its base. Where it emerges, a fringe of sheath tissue is left around the branch base as a collar. The base of the branch is surrounded by a sheath-like structure, which differs from the regular nodal sheaths in being usually scarious, brownish in color, and unvascularized, and in lacking stomata and a subjacent internode. This structure was described at length by Duval-Jouve (1864, as gaine basilaire) who followed Vaucher (1821) in considering it a protective structure for the branch bud, analogous to the bud scales of phanerogams. Milde (1867, p. 155) thoroughly discussed the Asthiille (Ochreola). He pointed out that it is always different in color from the branch sheaths, with short, blunt teeth. According to Milde, the ochreole does not grow from the branch but rather develops from the inner cylinder of the stem. He claimed it lacked commissures so was not of fused leaves, but of a single, toothed leaf. The outer (abaxial) angle is different from the others in being thick, with a vascular bundle, chlorophyllous cells, and scattered stomata. Thus the ochreola represents a bract with a midrib, in the axil of which the branch develops. Milde emphasized that the ochreole does not terminate an internode, as do the branch and stem sheaths. It belongs not to an internode, but rather to the whole branch. He also called attention to the similarity between this and the sheath subtending the juvenile plant as it develops from the embryo. On a later page in the same publication Milde (1867, p. 379) corrected and expanded his earlier description. The Asthiille, unlike a bract, belongs to the branch rather than the main axis, and is the first leaf whorl on the branch. He compared it to the first leaf (the prophyll) on most monocot branches. Janczewski (1876) described the initiating bud as forming a vegetative cone and a basal portion. As the vegetative cone develops, the upper part of the basal portion is elevated to form a rim around the vegetative cone, and this rim represents the first sheath of the branch. Janczewski found Milde's interpretation of this as a bract subtending the branch very odd (bien singuliere). DeBlock (1923) described the ochreole as membranous and becoming brown, with no trace of stomata, chlorophyll, or vascular tissue. Johnson (1937) in describing hydathodes in Equisetum leaves, commented on their absence on the ochreole, which is thin and usually devoid of vascular tissue. Even when vasculated, the ochreole

Comparative Ecology of Rubus Species (Rosaceae) I. Ecological Distribution and Life History Characteristics of Three Species, R. palmatus var. coptophyllus, R. microphyllus and R. crataegifolius

Abstract The ecological distribution and life history characteristics of three Rubus species, i.e., R. palmatus Thunb. var. coptophyllus (A. Gray) O. Kuntze, R. microphyllus L.f. and R. crataegifolius Bunge were investigated, with particular emphasis on the seasonal growth cycles, modes of the alternation of aerial organs, and patterns of dry matter allocation, and these features were critically compared with one another. It was found that seasonal changes of aboveground biomass are strongly related to the modes of cane alternation, to underground branching producing stolons, and to their dry matter allocation patterns. The modes of cane alternation, underground branching and dry matter allocation patterns were very similar in R. microphyllus and R. crataegifolius, taking about five months from May to September. But R. palmatus var. coptophyllus showed much more gradual replacement of aerial organs, extending over seven months from May to December. These three Rubus species are often predominant in the early successional stages of pioneer communities which develop after cutting of forests in central Japan, and differentiations of the above‐mentioned life history traits found in Rubus species seem to be related to the constraints inherent in their somewhat labile, changing environments, e.g., at the forest margin or clearings produced temporarily.

The influence of side-chains on the dilute-solution properties of three structurally related, bacterial anionic polysaccharides

Viscometric, calorimetric, and chiroptical data collected by using dilute aqueous solutions of the extracellular polysaccharides [Me 4N + salt form] from Pseudomonas elodea (S-60), Alcaligenes (ATCC 31555) (S-130), and Alcaligenes (ATCC 31961) (S-194) over a range of ionic strength (Me 4NCl concentrations) and temperature are reported. The data demonstrate that increasing the ionic strength of dilute solutions of the nonbranched S-60 at 25° promotes a distinctly co-operative, conformational transition over a narrow range of added salt concentration. Moreover, over the range of ionic strength examined, S-60 also undergoes a thermally reversible, conformational transition which exhibits no hysteresis: the temperatures at the midpoint of the sigmoidal transitions ( T M) increase moderately with increasing ionic strength. This conformational ordering has been monitored under conditions where S-60 does not gel. However, because both higher concentrations of S-60 at the same ionic strength, and higher ionic strengths at the same S-60 concentration, lead to gel formation, it is likely that the conformational ordering we have observed is the one involved in the gelation of S-60. The data also indicate that the two different modes of branching along the S-60 backbone present in S-130 (α- l-rhamnose and α- l-mannose linked to O-3 of the d-glucose after the d-glucuronic acid in the tetrasaccharide repeating-unit) and S-194 [β- d-glucopyranosyl-(1 → 6)-α- d-glucopyranosyl units linked to O-6 of the d-glucosyl residue before the d-glucosyluronic acid] mediate against conformational ordering. This is consistent with the fact that S-60 forms firm aqueous gels, whereas S-130 and S-194 are non-gel-forming, but give stable, highly viscous solutions. In addition, the measurements indicate that the carboxyl group in S-30 is in a screened, molecular environment. It is suggested that this screening could arise from hydrogen bonding involving the l-rhamnose- l-mannose side-chains.

Different modes of crack propagation in burning solid propellants

The motivation for this research came from the lack of proper understanding of propagation and branching processes in burning solid propellants. These processes are vital in defining safe operating conditions of high energy solid propellants and interpreting important phenomena during the initial phase of deflagration- todetonation transition (DOT). Several experiments have been conducted, and propellant samples have been recovered by rapid pressurization followed by depressurization. For different pressurization rates, four major modes of crack propagation and/or branching are observed. For very low dp/dt, burning occurs without crack propagation. For dp/dt in the order of 1.4 to 15 GPa/s, an existing crack propagates along its initial direction as a single crack (propagation mode). At high pressurization rates of 30 GPa/s or higher, multiple branching in various directions is observed (branched mode); and at intermediate dp/dt, single crack propagation is accompanied by local branching (mixed mode). The amount of surface area generated by mixed or branched modes is substantially higher than that of the single crack propagation mode, and in real motors, could cause sufficiently severe burning in the damaged zone to result in rocket motor failure.

Morphology and development of the ovarian artery in cattle in the fetal and neonatal periods

SummaryMorphology and development of the bovine ovarian artery during the fetal and postnatal periodsDevelopment and morphology of the ovarian artery was studied in 106, 9–40 week‐old fetuses and 14, 2–14 day‐old calves. Different factors were considered such as time‐dependent position and mode of branching from the aorta, the course of the ovarian artery in relation to the ovarian vein, and the artery's secondary distribution. Marked developmental changes which in time disappeared, become more prominent, or were reduced, could be demonstrated.

Immunohistochemical studies of the serotonergic supraependymal plexus in the mammalian ventricular system, with special reference to the characteristic reticular ramification.

Distributional and morphological features, especially characteristics of the ramification of serotonin-containing supraependymal fibers (SEF), were studied in the ventricular systems of mammals (mouse, rat, guinea pig, rabbit, cat, dog, monkey) by means of a modified peroxidase antiperoxidase technique, using antiserotonin antiserum prepared in our laboratory. SEF were present in all ventricular systems, except on the third ventricle floor and in the choroid plexus. The density of SEF was higher in the smaller species. In the rat, light- and scanning electron microscopical SEF were almost completely abolished 1 week after intraventricular administration of 5,6-dihydroxytryptamine. Ramification of SEF was complicated; the SEF formed a true network with frequent anastomosing. In the ventricular system of rats rendered hydrocephalic by kaolin administration, the mode of axonal branching in the supraependymal plexus could best be analyzed by the scanning electron microscope because the meshes of the plexus were spread out.

The role of ubiquinone in linking nitrate reductase and cytochrome o to the respiratory chain of Paracoccus denitrificans

Three alternatives of the mode of branching in the ubiquinone-cytochrome b region of the anaerobic respiratory chain of Paracoccus denitrificans were experimentally tested. It was found that the view that the constitutive cytochrome b-560 or b-566 serves as an electron donor for the nitrate reductase is incompatible with the proposed scheme of the cyclic electron flow in the bc 1 segment. By means of the extraction procedure, the extent of reduction of ubiquinone was determined in cells utilizing oxygen and nitrate in the presence of antimycin. It was found that the redox response of ubiquinone was consistent with what had been predicted by the pool model of Kröger and Klingenberg, extended for more than one terminal acceptor. Our results are in support of the assumption that in cells of P. denitrificans ubiquinol (QH 2) has a function of an electron donor both for nitrate reductase and cytochrome o.

Comparative morphology of the somatic karyotypes of vegetable amaranths and its phylogenetic significance.

Morphological and karyotypical analyses of five species of Amaranthus (sect. Blitopsis) have been undertaken. The species are found to be quite distinct, differing in height, mode of branching, shape as well as size of the leaf, structure of infloresence, nature of bract as well as utricle and mode of dehiscence of ripe utricle. Compared to the wild species, the cultivated ones show advanced characters due to selection. The karyotypes of all the species are very much asymmetric with variation in size as well as in form of chromosome sets. No two species are karyotypically alike. Evidently, the species differentiation in members of the section is caused by chromosome repatterning and in evolution of the species structural alterations of chromosomes are playing a key-role.

Crozier Formation in Byssochlamys Nivea

Crozier formation in Byssochlamys nivea was studied by means of scanning electron microscopy (SEM) and light microscopic techniques. The continuous recording of crozier formation by time lapse cinematography combined with karyological analyses revealed an important deviation from the classical scheme of crozier formation. In B. nivea the divisions of the two nuclei during crozier formation are not simultaneous (conjugate). First, the nucleus in the crook region divides followed by septum formation, and then the nucleus in the basal region undergoes nuclear division followed by septum formation. The three-dimensional arrangement of crozier chains was analyzed by SEM. Subsequent croziers are turned against each other at an angle of 120?. There are two modes of crozier chain branching: formation of one crozier, each, from the penultimate cell and from the fused terminal cell, and simultaneous formation of the two croziers from the penultimate cell. Crozier formation is a prominent feature in the dikaryotic stage of the majority of higher Ascomycetes. The classical scheme is based on Claussen's observations of the development of Pyronema confluens Pers. ex Tul. and other Discomycetes (Claussen, 1912). Later work on other fungi, e.g., Saccobolus kerverni (Crouan) Boud. (Carroll, 1968), Pyronema domesticum (Sow. ex Gray) Sacc. (Hung and Wells, 1971) and Neurospora crassa Shear & Dodge (Raju, 1980) seemed to confirm the general validity of the pattern of crozier formation derived from studies of Pyronema confluens. In all cases, however, data were obtained from sections of fixed material since the croziers usually are hidden within the developing fruiting bodies. As a consequence, the time course and details of crozier formation had to be reconstructed from different croziers in various developmental stages. In all such investigations there was incomplete information as a result. In our paper, crozier formation is analyzed in a more primitive organism, Byssochlamys nivea Westling, than P. confluens and others. In this ascomycete, the croziers and, later on, the asci, are surrounded by very scanty, loose welts of hyphae. To suppress even this presumably primitive form of a peridium, a suitable nutrient medium which allowed normal ascus formation without any cover of hyphae was developed. Crozier formation could then be studied by timelapse cinematography of living material combined with other techniques to reveal the karyology. As a result we have traced a complete course of crozier chain formation obtained from individual crozier initials. Important deviations from the classical scheme of crozier development were found.

The human thyrocervical trunk: configuration and variability reinvestigated.

Reinvestigation of the configuration of the human thyrocervical trunk revealed, that in the presently investigated specimens the dorsal scapular artery is a direct branch of the subclavian artery in approximately 75% of the cases, whereas in the remaining 25% it is derived from the thyrocervical trunk, either directly or via the transverse cervical artery (Nomina anatomica 1977). The internal thoracic artery participates in the thyrocervical trunk in more than 10% of the observed cases. Thus, both dorsal scapular and internal thoracic artery have to be considered as facultative branches of the thyrocervical trunk. According to our results, the subclavian artery must be considered as the most common site of origin of the dorsal scapular artery. This vessel may be replaced by another artery in about one fourth of the cases. A survey of studies on the origin of the dorsal scapular artery clearly demonstrates that it is not warranted to give an overall numerical proportion for the main modes of branching. As yet no satisfactory explanation for the high degree of variability of these subclavian branches has been given. Especially the widely held notion of differences related to race, which is based on Adachi's (1928) work, has turned out to be invalid. Interpretation of variability may rather be based, as a general concept, on the late acquisition of a thyrocervical trunk in phylogeny as well as in ontogeny.