Vegetative sentence example
The plants show great diversity in vegetative structure.
In this way we may distinguish, first, vegetative reproduction, the result of discontinuous growth of the tissues and cell-layers of the body as a whole, leading to (I) fission, (2) autotomy, or (3) vegetative budding; secondly, germinal reproduction, the result of the reproductive activity of the archaeocytes or germinal tissue.
A characteristic feature of the fungal vegetative plantbody (mycelium) is its formation from independent coenocytic tubes or cell-threads.
The formation of a massive body naturally involves the localization of the absorptive region, and the function of absorption (which in the simpler forms is carried out by the whole of the vegetative part of the mycelium penetrating a solid or immersed in a liquid substratum) is subserved by the outgrowth of the hyphae of the surface-layer of that region into rhizoids, which, like those of the Algae living on soil, resemble the root-hairs of the higher plants.
In order to effect this the individual chromosomes must become associated in some way, for there is no diminution in the actual amount of nuclear substance, and this leads to certain modifications in the division which are not seen in the vegetative nuclei.Advertisement
Palaeontological evidence conclusively proves that the surface of the earth has been successively occupied by vegetative forms of increasing complexity, rising from the simplest algae to the most highly organized flowering plant.
There is often a marked alternation in the production of vegetative and flowering shoots respectively; and, sometimes, from various circumstances, the flowering shoots are not produced for several years in succession.
The nucleus in its vegetative stage shows a fine network throughout containing in the meshes the so-called nuclear-sap; attached to the network are the chromosomes, in the form of small irregular masses, which have a strong affinity for the " basic dyes."
These, having the full equipment of the vegetative order, will now develop the inherent power of proliferation to a greater or lesser extent.
In other lichens we should expect to find the ascogenous hyphae arising directly from the vegetative hyphae as in Humaria rutilans among the ordinary fungi, where the process is associated with the fusion of vegetative nuclei.Advertisement
The difference between the various systems lies in the relative importance given to the reproductive characters on the one hand and the vegetative characters on the other.
Moreover, there is a generally recognised quasi-antagonism between the vegetative and reproductive processes, so that, other things being equal, anything that checks the one helps forward the other.
A check or arrest of growth in the vegetative organs seems to be a necessary preliminary to the development of the flower.
Owing, however, to the difference in their vegetative growth, they mature one after the other instead of simultaneously.
As with other plants, so in fungi the essential process of fertilization consists in the fusion of two nuclei, but owing to the absence of well-marked sexual organs from many fungi, a peculiar interest attaches to certain nuclear fusions in the vegetative cells or in young spores of many forms. Thus in Ustilagineae the chlamydospores, and in Uredineae the teleutospores, each contain two nuclei when young, which fuse as the spores mature.Advertisement
Physiologically, any cell or group of cells separated off from a hypha or unicellular fungus, and capable of itself growing out - germinating - to reproduce the fungus, is a spore; but it is evident that so wide a definition does not exclude the ordinary vegetative cells of sprouting fungi, such as yeasts, or small sclerotium like cell-aggregates of forms like Coniothecium.
In addition to sporangia and the conidial spores referred to, some Mucorini show a peculiar mode of vegetative reproduction by means of gemmae or chlamydospores - i.e.
In some forms we find definite male and female sexual organs (Sphaerotheca, Pyronema, &c.), in others the antheridium is abortive or absent, but the ascogonium (oogonium) is still present and the female nuclei fuse in pairs (Lachnea stercorea, Humaria granulata, Ascobolus furfuraceus); while in other forms ascogonium and antheridium are both absent and fusion occurs between vegetative nuclei (Humaria rutilans, and probably the majority of other forms).
The ascocarps can be distinguished into two portions, a mass of sterile or vegetative hyphae forming the main mass of the fruit bod y, and surrounding the fertile ascogenous hyphae which bear at their ends the asci.
Reproduction is chiefly effected by the vegetative method.Advertisement
In all the multicellular plants of this group which have been adequately investigated, vegetative multiplication by means of what are known as hormogonia has been found to occur.
Special provision for vegetative multiplication is not common among Chlorophyceae.
In Characeae no fewer than four methods of vegetative reproduction have been described, and the facility with which buds and branches are in these cases detached has been adduced as an evidence of affinity with Bryophyta, which, as a class, are distinguished by their ready resort to vegetative reproduction.
When a species resorts to both methods, it is generally found that the asexual method prevails in the early part of the vegetative period and the sexual towards the close of that period.
The proembryonic branches of Characeae, one of the means of vegetative reproduction already referred to, are so called because they repeat the characters of the proembryo.Advertisement
Of the small family of the Tilopteridaceae our knowledge is as yet inadequate, but they probably present the only case of pronounced oogamy among Phaeosporeae.;.They are filamentous forms, exhibiting, however, a tendency to division in more than one plane, even in the vegetative parts.
Vegetative multiplication occurs only sparingly in Rhodophyceae.
It is possible, however, that the tetraspore formation should be regarded as comparable with the prolific vegetative reproduction of Bryophyta, and in favour of this view there is the fact that the tetraspores originate on the thallus in a different way from carpospores with which the spores of Bryophyta are in the first place to be compared; moreover, in certain Nemalionales the production of tetraspores does not occur, and the difficulty referred to does not arise in such cases.
While even in such cases it is obvious that interesting stages in the life of the plant may escape notice altogether, in the cases of those plants the reproduction of which is unknown, and which have been named and placed on the analogy of the vegetative parts alone, there is considerable danger that a plant may be named as a distinct species which is only a stage in the life of another distinct and perhaps already known species.
In the case of the freshwater algae, however, belonging to the Chlorophyceae and Cyanophyceae, although they required to be immersed during the vegetative period, the reproductive cells are often capable of resisting a considerable degree of desiccation, and in this condition are dispersed through great distances by various agencies.
Far more important is the vegetative, or "natural" increase, through the excess of births over deaths.
Panaetius had referred two faculties (those of speech and of reproduction) to animal impulse and to the vegetative " nature " (01,o-cs) respectively.
In these Vegetative cases no cilia have been observed, and there is a state.
An arthrospore, however, is not a true spore but merely an ordinary vegetative cell which separates and passes into a condition of rest, and such may occur in forms which form endospores, e.g.
Vegetative body unicellular; spheroidal, cylindrical or spirally twisted; isolated or connected in filamentous or other growth series.
Vegetative cells, cylindric but curved more or less spirally.
In the first place, the extremely small size and isolation of the vegetative cells place the protoplasmic contents in peculiarly favourable circumstances for action, and we may safely conclude that, weight for weight and molecule for molecule, the protoplasm of bacteria is brought into contact with the environment at far more points and over a far larger surface than is that of higher organisms, whether - as in plants - it is distributed in thin layers round the sap-vacuoles, or - as in animals - is bathed in fluids brought by special mechanisms to irrigate it.
To other monocotyledonous families the resemblances are merely of adaptive or vegetative characters.
Small tuberous shoots, comparable on a large scale with the bulbils of Lycopodium Selago, are occasionally produced in the axils of some of the persistent leaf-bases; these are characteristic of sickly plants, and serve as a means of vegetative reproduction.
The anatomical structure of the vegetative organs of recent cycads is of special interest as affording important evidence of relationship with extinct types, and with other groups of recent plants.
Sequoia sempervirens, the fertile branches bear leaves which are less spreading than those on the vegetative shoots.
What the vegetative increase has been since then (for there has been no immigration) is purely conjectural, as there are no available returns of births and deaths upon which an estimate can be based.
In some species branches of the rhizome with tuberous internodes are formed, which serve as a means of vegetative reproduction.
A highly specialized means of vegetative reproduction is seen in the tubers of Phylloglossum and the embryos of some Lycopods.
The sporangia are borne in groups (sori) on the under surface of the leaves; sometimes the fertile leaves differ more or less from the purely vegetative ones.
In some apogamous Ferns sporangia may occur on the prothallus and the vegetative organs of the sporophyte may also occur singly.
The development of the sporocarp shows that it corresponds to a pinna, although when mature it may appear to occupy a ventral position in relation to the vegetative portion of the leaf.
At the present day Gallego, which is simply Portuguese variously modified and with a development in some respects arrested, is much less important than Catalan, not only because the Spaniards who speak it (i,8oo,ooo) are fewer than the Catalans (3,500,000), but also because, its literary culture having been early abandoned in favor of Castilian, it fell into the vegetative condition of a provincial patois.
In Ulodendron the large circular, distichously arranged prints were supposed to have been formed by the pressure of the bases of sessile cones, though this interpretation of the scars is open to doubt, and it is now more probable that they bore deciduous vegetative branches; in the Halonial branches characteristic of the genus Lepidophloios the tubercles may perhaps mark the points of insertion of pedunculate strobili.
We will now describe some of the fructifications, which are grouped under generic names of their own; these genera, as having a more natural basis, tend to supersede the artificial groups founded on vegetative characters.
In many fern-like plants of this period the fronds were dimorphic, the fertile leaves or pinnae having a form quite different from that of the vegetative portions.
The family Botryopterideae appears to have included a number of other genera, though in most cases the evidence from vegetative structure is alone available.
On the other hand there was the far more complex Marattiaceous type, strikingly similar in both vegetative and reproductive characters to the recent members of the family.
In the first-named plant the structure, both of the vegetative and reproductive organs, is known, and the evidence, from comparison and association, is sufficiently strong.
Heterangium shows, on the whole, a decided preponderance of Filicinean vegetative characters, though in the leaf-traces and the secondary tissues the Cycads are approached.
In the case of Lyginodendron the Crossotheca occurs in connexion with the vegetative parts of the frond.
This is the first case in which the pollen-bearing organs of a Ptoridosperm have been identified with certainty It will be seen that, while the seeds of Lyginodendron were of an advanced Cycadean type, the microsporangiate organs were more like those of a Fern, the reproductive organs thus showing the same combination of characters which appears in the vegetative ct pc. A, Micropylar region.
Seed, attached to a branch of the rachis bearing two vegetative leaflets.
In 1905 Grand' Eury discovered the seeds of Pecopteris Pluckeneti, an Upper Coal Measure species, attached, in immense numbers, to the fronds, which are but little modified as compared with the ordinary vegetative foliage.
The male sporophylls are similar in form to the vegetative leaves, but smaller; sunk in their parenchyma are numerous tubular loculi, containing large pollen-grains, which are pluricellular like those of Cordaites; the female fructification had not yet been identified with certainty.
In his account of some plants from the Coal Measures of Kansu (Map A, IV.) Dr Krasser has drawn attention to the apparent identity of certain leaf-fragments with those of Naeggerathiopsis Hislopi, a typical member of the Glossopteris flora; but this plant, so far as the evidence of vegetative leaves may be of value, differs in no essential respects from certain species of a European genus Cordaites.
Equisetites columnaris, a common fossil in the Jurassic plant-beds of the Yorkshire coast, represents another type with relatively stout and occasionally branched vegetative shoots, bearing leaf-sheaths very like those of Equisetum maximum and other Horsetails.
Important additions to our knowledge of the fertile leaves and rhizomes of certain Rhaetic species of Dictyophylium and other genera have recently been made by Professor Nathorst of Stockholm, and Professor Richter of Quedlinburg has made a thorough investigation of the vegetative organs of Hausmannia,.
The evidence adduced by Nathorst and some other writers is, however, not convincing; until we find well-preserved sporocarps in connection with vegetative fronds we prefer to keep an open mind as regards the position of Sagenopteris.
This form of stem, of a habit entirely different from that of recent Cycads and extinct Bennettites, points to the existence in the Mesozoic era of another type of Gymnosperm allied to the Bennettitales of the Jurassic and Cretaceous periods by its flowers, but possessing a distinctive character in its vegetative organs.
Coniferous twigs are very common in Mesozoic strata, but in most cases we are compelled to refer them to provisional genera, as the evidence of vegetative shoots alone is not sufficient to enable us to determine their position within the Coniferae.
We have not merely the striking resemblance of vegetative shoots to those of recent species of Araucaria and Agathis, e.g.
Among the more abundant Conifers of Jurassic age may be mentioned such genera as Thuytes and Cupressites, which agree in their vegetative characters with members of the Cupressineae, but our knowledge of the cones is far from satisfactory.
Pinites Dunkeri, P. Solmsi, &c.; specimens of seeds and vegetative shoots are recorded also from Spitsbergen and other regions.
Maximum vegetative growth of field horsetail occurs in July.
When used regularly in the vegetative stage it does help keep the plant lush, healthy and stress free.
Much of their life cycle is spent as vegetative mycelium, exploiting complex substrates.
This time of year is a perfect time to be lifting and splitting herbaceous plants before they put on too much vegetative growth.
Has there been subsequent vegetative propagation of material derived from seed?
Clonal propagation -- asexual reproduction, including vegetative spread, producing a clone of the parent plant.
Vegetative reproduction - a reproductive process that is asexual and so does not involve a recombination of genetic material.
In the UK, the reproduction of Japanese knotweed is purely vegetative.
Patients who are permanently vegetative or minimally aware are not usually admitted and patients with tracheotomies are only admitted under exceptional circumstances.
In situations where seedlings cannot establish (i.e. where vegetation management does not produce patches of bare soil) only vegetative spread occurs.
For instance Jennett and Teasdale  describe the case of a man who remained vegetative for 18 years.
E, Dry spores showing the ex F, Sterile vegetative shoot.
In early inquiries a great point was made of the prevention of putrefaction, and work was done in the way of finding how much of an agent must be added to a given solution, in order that the bacteria accidentally present might not develop. But for various reasons this was an inexact method, and to-day an antiseptic is judged by its effects on pure cultures of definite pathogenic microbes, and on their vegetative and spore forms. Their standardization has been effected in many instances, and a water solution of carbolic acid of a certain fixed 'strength is now taken as the standard with which other antiseptics are compared.
The lowest Hepaticae have an extremely simple vegetative structure, little more advanced than that found in some of the higher Green Algae and very much simpler than in the large Red and Brown Seaweeds.
If the axis of such a sporogonium were prolonged downwards into the soil to form a fixing and absorptive root, the whole structure would become a physiologically independent plant, exhibiting in many though by no means all respects the leading features of the sporophyte or ordinary vegetative and spore-bearing individual in Ptericlophytes and Phanerogams. These facts, among others, have led to the theory, plausible in some respects, of the origin of this sporophyte by descent from an Anthoceros-like sporogonium (see PTERIDOPHYTA).
Frequently, also, a considerable differentiation of vegetative tissue occurs in the wall of the spore-capsule itself, and in some of the higher forms a special assimilating and transpiring organ situated just below the capsule at the top of the seta, with a richly lacunar chlorophyllous parenchyma and stomata like those of the wall of the capsule in the Anthocerotean liverworts.
Physiological and Morphological Di,fferentiation.The first indication of this differentiation in the vegetative body of the plant can be seen not only in the terrestrial green plants which have been particularly referred to, but also in the bulkier seaweeds.
Hemi-hydrophytes (swamp plants, marsh plants, &c.).Plants riose vegetative organs are partly submerged and partly aerial; lucheria terrestris, Philonotis fontana, Sca pan-ia undulata, Maria spp., Salvinia ivatans, Azolla spp., Equisetum limosum, Typha rgustifolia, Phragmites communis, Scirpus lacustris, Nymphaea tea, Oenanthe fistulosa, Bidens cernua.
The plants show great diversity in vegetative structure, which together with the character and mode of dehiscence of the fruit afford a basis for the subdivision of the order into tribes, eleven of which are recognized.
Before leaving the pollen-sac a division takes place in the pollengrain into a vegetative cell or cells, from which the tube is developed, and a generative cell, which ultimately divides to form the male cells (see Angiosperms and Gymnosperms).
Vegetative reproduction can be carried out at any time by a plant.
He would have been in a vegetative state for the rest of his life.
To flower freely, vegetative growth must not be more than moderate.
In addition to low levels of seed production, vegetative spread is very slow.
Planting vegetative covers, strict erosion management and implementing beneficial farming methods are just a few of the many possible approaches to soil conservation.
Eventually these head rounds evolved to become both crowns made from precious metals and jewels and vegetative wreaths made to hang on the wall.
Patching is never done for contact lens patients, whose eyes are at a greater risk of a Pseudomonas infection, nor when the cause of an abrasion is due to vegetative matter, such as a tree branch.
This is especially important if vegetative matter is the cause of the abrasion.
Unless treated with a diet that includes a mixture of oils called Lorenzo's oil, the disease will result in paralysis, hearing loss, blindness, vegetative state, and death.
Most recently, Michael Corinthos III (A.J.'s biological son) was shot in the head and remains in a vegetative state.
The crash left active duty Marine Graziano in a permanently vegetative state and on life support.
The vegetative and sensitive souls which the Aristotelians had introduced to break the leap 1 Ouvres, iv.
Especially noteworthy in the germinal budding of Margellium is the formation of the entocodon, as in the vegetative budding of the indirect type.
Thallophyta are the most lowly organized plants and include a great variety of forms, the vegetative portion of which consists of a single cell or a number of cells forming a more or less branched thallus.
Filicales and Gymnosperms, and known as the Cycadofihices, a group in which, curiously enough, the reproductive organs remained undiscovered for some time after the anatomy of the vegetative organs was sufficiently well known to afford clear evidence of their true affinities.
This was accompanied by a vegetative organization of which there is no obvious foreshadowing.
The floral structure is so curious that perhaps less attention has been paid to the vegetative organs than the peculiarities of their organisation demand.
This analysis, if correct, indicates that the vegetative increase of the whites has been greater than that of the Africans and mixed races.
Aquinas regards the souls of men, like the angels, as immaterial forms; and he includes in the soul-unit, so to speak, not merely the anima rationalis of Aristotle, but also the vegetative, sensitive, appetitive and motive functions.
The centrosomes which play so important a part in cell division may be found either lying within or at one side of the nucleus in the vegetative condition of the cell.
The fact that it is possible to propagate these cells of one animal for years in other animals of the same species, without any loss of their vegetative vitality, suggests that this continued growth is kept up by a growth-stimulating substance present in the proper species of animal; this substance, however, has not the power of transforming the normal tissue into a cancerous one.
The descendants of such cells will become more and more undifferentiated, thereby developing an increased vegetative activity.
Oertel finds an explanation of this want of complete celldifferentiation, loss of function, and acquired vegetative activity in the non-homogeneous character of the nuclear chromatin elements of the cell, and maintains that the different properties of the cell are carried and handed down by the different orders of chromatin loops.
A defect in co-ordination allows the stimulated active vegetative cellular elements, or the more fully differentiated tissue, to over-develop and so form tumours, simple or malignant.
In the Telosporidia (comprising the Gregarines, Coccidia and Haemosporidia), sporulation does not begin until the close of the vegetative or trophic period, i.e.
Means of vegetative propagation are general.
There is but little immigration and the vegetative increase is low.
Aristotle had imputed to all living beings a soul, though to plants only in the sense of a vegetative, not a sensitive, activity, and in Moleschott's time many scientific men still accepted some sort of vital principle, not exactly soul, yet over and above bodily forces in organisms. Moleschott, like Lotze, not only resisted the whole hypothesis of a vital principle, but also, on the basis of Lavoisier's discovery that respiration is combustion, argued that the heat so produced is the only force developed in the organism, and that matter therefore rules man.
There we find an association of nuclei either by the fusion of two similar cells as described by Christmann or by the migration of the nucleus of a vegetative cell into a special cell of the aecidium.
Generally, however, the flower-bearing portion of the plant is sharply distinguished from the foliage leafbearing or vegetative portion, and forms a more or less elaborate branch-system in which the bracts are small and scale-like.
This view is still maintained by those who differentiate two acts of fertilization within the embryo-sac, and regard that of the egg by the first male-cell, as the true or generative fertilization, and that of the polar nuclei by the second male gamete as a vegetative fertilization which gives a stimulus to development in correlation with the other.
The number of chromosomes in the nucleus of the two spores, pollen-grain and embryo-sac, is only half the number found in an ordinary vegetative nucleus.
In Vegetative shoot has the capacity to form a new plant if placed repro- duction.
A relation between such vegetative distribution buds and production of flower is usually marked.
Viviparous plants are an illustration of substitution of vegetative buds for flower.
We readily recognize in them nowadays the natural classes of Dicotyledons and Monocotyledons distinguished alike in vegetative and in reproductive construction, yet showing remarkable parallel sequences in development; and we see that the Dicotyledons are the more advanced and show the greater capacity for further progressive evolution.
Distribution by seed appears to satisfy so well the requirements of Angiosperms that distribution by vegetative buds is only an occasional process.