Structural positioning and orientational development in the vegetative organs of Poa pratensis with special reference to the rhizome axillary buds

1972 ◽  
Vol 50 (4) ◽  
pp. 743-750 ◽  
Author(s):  
John E. Fisher
Keyword(s):  
Apical Meristem ◽  
Poa Pratensis ◽  
Bilateral Symmetry ◽  
Main Stem ◽  
Axillary Bud ◽  
Initial Activity ◽  
Vegetative Organs ◽  
Initial Deviation ◽  
Lateral Bud ◽  
The Many

The apical meristem of P. pratensis is hemi-ellipsoidal, the plane of bilateral symmetry being readily recognizable. On each side of the apex a prominent pair of tiers of surface cells straddles the line of the plane of symmetry from the upper limit of the active promeristem and extends basipetally into the first and frequently second foliar primordia. Initiation of a new foliar primordium (phytomer) is centered in one or the other of the paired tiers. Occasionally, a single cell in a tier appears to undergo initial mitotic activity. The specific tier of initial activity determines the deviation from symmetry of the whole phytomer including that of the leaf at the top of the phytomer and of the lateral bud at its bottom. The subtending leaf does not determine the deviation from the plane of symmetry of the axillary bud. The first leaf of the axillary bud (not the prophyll) is positioned with its point of origin, hence its midrib, displaced away from the plane of symmetry of the main stem and with its larger semicircumference towards the main stem. Thus the deviation from bilateral symmetry of all the organs of the phytomer and the initial deviation from symmetry of the organs produced by the axillary bud are determined originally by the specific tier of cells in the promeristem of the main shoot that is stimulated into initial activity. This initial orientation of the axillary bud is the first of the many orientations that determines the pathway through the soil that the rhizome will ultimately follow.

Growth forms in the Alismatales. II. Two rhizomatous species: Sagittaria lancifolia and Butomus umbellatus

1979 ◽  
Vol 57 (21) ◽  
pp. 2353-2373 ◽  
Author(s):  
S. M. Lieu
Keyword(s):  
Morphological Study ◽  
Growth Form ◽  
Bilateral Symmetry ◽  
Life Cycles ◽  
Axillary Bud ◽  
Growth Forms ◽  
Sagittaria Lancifolia ◽  
Adult Form ◽  
Lateral Bud ◽  
Made In

A comparative morphological study of Sagittaria lancifolia and Butomus umbellatus over their life cycles was undertaken. The two are very similar in adult form, characterized by apical bifurcation to form inflorescence and continuation growth as in other members of the Alismatidae.and also by rhizomatous growth with a subterminal apex. Embryo and seedling stages in S. lancifolia are comparable to other members of the Alismataceae previously studied. Rhizomatous form and bilateral symmetry are secondarily acquired during ontogeny. The inflorescence is leaf opposed and S. lancifolia is organizationally similar to other species of Alismataceae with upright vegetative axes. From this, a sympodial interpretation of the rhizome may be made. In contrast, the bilaterally symmetric growth form in Butomus is manifested from the start. The leaf-subtended inflorescence and other features of organization suggest that it cannot easily be compared with S. lancifolia or other members of Alismataceae. Here, a stronger case may be made for a monopodial construction. Axillary bud distributions support these conclusions. In addition, both species branch by a relatively precocious lateral bud associated topographically with the inflorescence.

MORPHOLOGICALLY DISTINCT STAGES IN THE GROWTH AND DEVELOPMENT OF RHIZOMES OF POA PRATENSIS L. AND THEIR CORRELATION WITH SPECIFIC GEOTROPIC RESPONSES

1965 ◽  
Vol 43 (10) ◽  
pp. 1163-1175 ◽  
Author(s):  
John E. Fisher
Keyword(s):  
Cross Section ◽  
Growth And Development ◽  
Apical Meristem ◽  
Poa Pratensis ◽  
Soil Surface ◽  
Leaf Primordium ◽  
Primary Stage ◽  
Secondary Stage ◽  
Small Pore ◽  
Tertiary Stage

Three distinct stages in the growth and development of the rhizomes of Poa pratensis L. can be distinguished. The names, primary, secondary, and tertiary are proposed to identify the stages. Primary stage rhizomes produce cataphylls elliptical in cross section, and poreless, or with a very small pore. Cataphyll primordia, initiated by the apical meristem, develop disproportionately, producing a hood-like cowling enclosing the apical meristem. The opening partially or completely closes by ontogenetic fusion. The geotropic response is plagiotropic Secondary stage rhizomes produce cataphylls with a marked longitudinal invagination. They are seldom poreless, and then only early in this stage. The apices are similar to primary stage apices. The geotropic response is diageotropic. Tertiary stage rhizomes progressively exhibit characteristics of true aerial shoots. Cataphylls develop a rudimentary leaf blade, ligule, and buliform-cell leaf-closure apparatus. However, a collar between blade and sheath does not form until the rhizome reaches the soil surface. The apex progressively develops the broad shield-shaped leaf primordium characteristic of aerial shoots. The geotropic response becomes strongly negatively orthogeotropic. Both the secondary and the tertiary stages are initiated by a change in the morphology of the apex and the cataphyll that precedes changes in the geotropic response of the rhizomes.

scholarly journals Plant Parasitic Nematodes and their management in crop production: a review

2021 ◽  
Vol 4 (2) ◽  
pp. 327-338
Author(s):  
Honey Raj Mandal ◽  
Shambhu Katel ◽  
Sudeep Subedi ◽  
Jiban Shrestha
Keyword(s):  
Crop Production ◽  
Bilateral Symmetry ◽  
Cultural Control ◽  
Crop Damage ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Cyst Nematodes ◽  
The World ◽  
The Many ◽  
Plant Parasitic

Plant Parasitic Nematodes are small worm like transparent, bilateral symmetry, pseudocoelomate, multicellular, free living or parasitic microorganism which are predatory, aquatic, terrestrial, entopathogenic, ectoparasite, endoparasite, semi-endoparasite or sedentary. They cause substantial problems to major crops throughout the world, including vegetables, fruits, and grain crops. The root knot and cyst nematodes are economically important pests in numerous crops. Crop damage from nematodes is not readily apparent in most cases, and it often remains hidden by the many other factors limiting plant growth. In the past, the control of the nematodes has been based on the synthetic nematicides, the number of which has been drastically restricted in the EU because of their environmental side effects and subsequent restriction in European Union (EU) rules and regulations. Many other methods like cultural control, biological control, use of biotechnological tools and methods, use of resistant cultivars are tested and proven successful in controlling different species of nematodes all over the world. Alternatively, combinations of the different methods are proven to be highly effective both economically and environmentally.

scholarly journals Enhancement of growth and increased productivity of fresh herb and aromatic oil in basil plant by foliar application with stigmasterol

1970 ◽  
pp. 07-13
Author(s):  
Ahmed A. El-Tantawy ◽  
Samah N. Azoz
Keyword(s):  
Vegetative Growth ◽  
Foliar Application ◽  
Volatile Oil ◽  
Main Stem ◽  
Anatomical Structures ◽  
Vegetative Organs ◽  
Enhancing Effect ◽  
Growing Seasons ◽  
The Impact ◽  
Growth Characters

The present study was conducted through the two growing seasons of 2017 and 2018 to disclose the impact of foliar application with different concentrations of stigmasterol (0, 25, 50, 75 and 100 ppm) on vegetative growth characters, yield of fresh herb/plant, anatomical structures of vegetative organs (main stem and leaves) and percentage and constituents of aromatic oil of basil plant. The obtained results indicated that stigmasterol application had a enhancing effect on growth and productivity as well as on the percentage and composition of volatile oil of basil plant and the maximum promotion was detected at 100 ppm stigmasterol. Such treatment induced favorable changes in the anatomical structures of vegetative organs.

Xylary union between elongating lateral branches and the main stem in Populus deltoides

1983 ◽  
Vol 61 (4) ◽  
pp. 1040-1051 ◽  
Author(s):  
Philip R. Larson ◽  
David G. Fisher
Keyword(s):  
Populus Deltoides ◽  
Secondary Xylem ◽  
Cambial Activity ◽  
Main Axis ◽  
Main Stem ◽  
Leaf Trace ◽  
Primary Xylem ◽  
Lateral Bud ◽  
Lateral Branches ◽  
Secondary Vessels

The vasculature of elongating lateral branches was examined to determine how vessels produced in the branch unite with those produced in the main stem axis to form a continuous transport system. In a previous study it was found that differentiation of both primary and secondary xylem in a lateral bud or branch is independent of that in the main axis; i.e., xylem does not differentiate into the bud or branch from the main axis. When serial sections of the nodal region are followed downward, the bud vascular cylinder merges with that of the main axis and the adaxially situated bud traces (those nearest the stem) enter the bud gap margin first. The primary vessels of these bud traces differentiate in an oblique downward path along the margins of the bud gap, and they form radial files of primary vessels that lie adjacent to primary xylem of leaf traces in the stem. Traces situated more abaxially in the bud (those farther from the stem) contribute to other radial files of primary vessels, each of which lies progressively closer to the bud gap. Secondary xylem is initiated in the stem before it is in the branch. Consequently, the last-formed metaxylem vessels of the bud traces are continuous with secondary vessels of the stem. These latter vessels lie in the stem secondary xylem immediately external to primary xylem from the bud. Secondary xylem in the branch is initiated when foliage leaves and internodes mature. Secondary vessels formed in the branch traces are continuous with secondary vessels in the stem; these vessels are embedded in a matrix of fibers. Because cambial activity is more vigorous in the stem than in the branch, two vessels that are radially adjacent in the branch may be widely separated by fibers in the stem. The central trace of the axillant leaf enters the gap immediately below the last branch traces; at this level in the stem the leaf trace vasculature is entirely primary. The stem secondary xylem that overlies the leaf trace is continuous with that in the axillary branch.

Response

2016 ◽  
Vol 10 (3) ◽  
pp. 457-467 ◽  
Author(s):  
Richard J. Evans
Keyword(s):  
Civil War ◽  
The Real ◽  
Initial Deviation ◽  
History Of ◽  
Counterfactual History ◽  
The Many ◽  
The Way

This reply to the critiques by Daniel Woolf, Cass R. Sunstein and Daniel Nolan of my book Altered Pasts: Counterfactuals in History (Brandeis University Press, 2013), takes each of their contributions in turn, and reasserts the centrality to counterfactual history of positing definite, long term alternative timelines rather than a vague claim that things might have turned out differently to the way they actually did (for example, if the Confederacy had won the Civil War, slavery might still exist in the usa). Such alternate timelines have no claim to either truth or utility since they ignore the many possible contingencies that would most likely have taken place following the initial deviation from the real timeline of history.

Etude cinétique de quelques événements lies à une levée de dominance apicale par décapitation ou ablation de l'axe principal à différents niveaux chez la Tomate, Lycopersicum esculentum

1980 ◽  
Vol 58 (2) ◽  
pp. 281-294
Author(s):  
Kim Anh Ha Ngoc
Keyword(s):  
Apical Dominance ◽  
Main Axis ◽  
Main Stem ◽  
Axillary Buds ◽  
Axillary Bud ◽  
Lycopersicum Esculentum ◽  
Tomato Plants ◽  
Different Levels

In intact tomato plants, axillary buds are completely inhibited by the main apex. A release from apical dominance is obtained by decapitation or excision of the main axis at different levels. These excisions lead to a wave of mitotic reactivation along the main stem which progresses in the basipetal way and is followed by an activation of axillary bud in the acropetal direction, from the base to the axillary bud apex. After release from apical dominance, axillary buds don't react equally. There is a basipetal gradient of their capacity of outgrowth. In the younger subapical axillary buds, mitotic reactivation is the first step observed (after 3 h); the cellular elongation occurs after 3–6 h, and foliar organogenesis begins only after 24 h. The basal axillary buds are reactivated much later. Adult leaves don't play any role on their axiliaries: the total defoliation of the plant does not lead to the outgrowth of all the axillary or cotyledonary buds.

Lateral branch vascularization: its circularity and its relation to anisophylly

1981 ◽  
Vol 59 (12) ◽  
pp. 2577-2591 ◽  
Author(s):  
Philip R. Larson ◽  
Jennifer H. Richards
Keyword(s):  
Populus Deltoides ◽  
Lateral Branch ◽  
Main Stem ◽  
Axillary Bud ◽  
The Third ◽  
Organizational Pattern ◽  
Lateral Branches ◽  
Bud Initiation ◽  
Derivatives Of ◽  
Lower Stem

The vasculature of elongating lateral branches of Populus deltoides Bartr. ex Marsh. was examined to determine how vascular continuity was attained around the entire branch circumference. In a previous study it was found that a pair of original bud traces (A, A′) gave rise to three pairs of bud traces in sequence (a, a′; b, b′; g, g′) that vascularized the axillary bud; the original bud traces then continued upward in the main stem axis. In this study we demonstrated that the lower, abaxial part of the branch cylinder was vascularized by derivatives of the first pair of bud traces (a, a′), the lateral parts primarily by derivatives of the second pair of bud traces (b, b′), and the upper, adaxial part by derivatives of the third pair of bud traces (g, g′). Thus, the organizational pattern for branch vascularization was established during the earliest stages of axillary-bud initiation. Leaves on all lateral branches were anisophyllous; the condition was related to the position of leaves in the phyllotactic array and to their vascularization. The smallest leaves always occurred on the upper branch side and their central traces were diverted upward in the main stem vascular cylinder. The largest leaves were usually on the lower stem side and their central traces were diverted downward. Some first-formed leaves were falcate, and the lateral traces serving the suppressed sides of their laminae were also found to be diverted upward in the main stem axis. It was suggested that both the small anisophyllous and the falcate leaves might result from a lower nutritional status because of their upward-directed leaf traces.

Réactivation du bourgeon cotylédonnaire du Pois en réponse à la kinétine

1981 ◽  
Vol 59 (5) ◽  
pp. 590-603 ◽  
Author(s):  
Arlette Nougarède ◽  
Jacques Rembur ◽  
Pierre Rondet
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Apical Meristem ◽  
Hormonal Treatment ◽  
Axillary Bud ◽  
2C Dna Content ◽  
Bud Growth ◽  
Lag Period ◽  
Elongation Process ◽  
Three Components

For three components (apical meristem, subapical internodes, and foliar apparatus) of Pisum sativum (cv. nain hâtif d'Annonay) cotyledonary buds, DNA microdensitometry, mitotic indices, and release of growth have been used to detect changes produced by kinetin applications (50 μg/mL). One kinetin treatment is sufficient to release the cell cycle, but continuous kinetin supply is necessary to maintain bud elongation. At the apical, subapical, and foliar levels, inhibited cotyledonary buds contain a majority of nuclei with 2C DNA content, in the G1 phase of the cell cycle. Following hormonal treatment, the prereplicative phase of the noncycling cells is at least 6 h in the whole bud. The lag period for the release of bud growth is between 15 and 23 h in subapical regions (first and second internodes) and between 23 and 38 h at the foliar level. At subapical and foliar levels, a few mitoses precede and then follow the elongation process. The first mitoses are from G2 nuclei of the inhibited bud. The following ones, more numerous, are from noncycling cells of inhibited buds, which have entered the S phase in response to kinetin application. The degree of inhibition of an axillary bud, estimated by the distribution of the DNA content in its three components, conditions the events induced by hormonal treatment or decapitation. The discussion shows how the knowledge of the original nuclear states of inhibited buds is necessary to understand axillary bud reactivation.

Axillary bud traces in certain dicotyledons

1968 ◽  
Vol 46 (2) ◽  
pp. 169-175 ◽  
Author(s):  
J. J. Shah
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Ontogenetic Development ◽  
Leaf Trace ◽  
Axillary Bud ◽  
Syzygium Cumini ◽  
Complete Ring ◽  
The Family ◽  
Vascular Structures ◽  
Primary Vascular System

The ontogenetic development of the axillary bud traces in two species of the family Verbenaceae, Clerodendrum inerme L. and C. splendens Gaertn. and one species of the family Myrtaceae, Syzygium cumini L., is described.Initially the two bud traces differentiate as branches of the leaf trace complex of the subtending leaf. Its further course in the bud may be due to direct differentiation of bud meristem cells as in Syzygium, or by the process of dedifferentiation and redifferentiation of certain sectors of the ground meristem intervening between the bud and the leaf trace of the subtending leaf as in Clerodendrum. Consequent to their further differentiation in the bud, the development of the primary vascular meristem of the bud occurs, initially as two arcs, later as an incomplete ring, and finally as a complete ring. It consists of residual meristem and procambium strands. The procambium strands form an anastomosing pattern of primary vascular system of the bud. Their ultimate origin can be traced to the two bud traces.An incorrect histogenic picture of the developing primary vascular system of a growing bud is obtained if one considers the vascular configurations of an arc or a complete or incomplete ring as bud traces. This histogenic development is a result of morphogenic interaction between the apical meristem of the bud and acropetally developing procambium strands of the bud trace. The vascular structures described as arcs, horseshoe-shaped, or ring are the phasic histogenic expressions of the gradual differentiation of the primary vascular system of the bud.

Sign in / Sign up

Export Citation Format

Share Document