The rotated-lamina syndrome. IV. Relationships between rotation and symmetry in Magnolia and other cases

1994 ◽  
Vol 72 (1) ◽  
pp. 25-38 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Key Words ◽  
Shoot Apex ◽  
Leaf Development ◽  
Leaf Primordia ◽  
The State ◽  
Axillary Buds ◽  
Reverse Direction ◽  
Ulmus Glabra ◽  
Young Leaves

Further variations of the rotated-lamina syndrome are described in Magnolia spp. and Rhamnus imeretinus, as well as an abnormal adult shoot of Ulmus glabra without lamina rotation. All magnolias investigated show lamina rotation, but there are four possible forms of shoot symmetry: (i) dorsiventral distichous shoots with the form of rotated-lamina syndrome previously described, i.e., laminae of young leaves all face towards the same (upper) side of the bud or towards the parental axis in axillary buds; (ii) another form of dorsiventral symmetry in which lamina rotation occurs in the reverse direction; (iii) spiral phyllotaxis with laminae rotated to face up the genetic spiral; and (iv) spiral phyllotaxis with laminae rotated to face down the genetic spiral. Shoot symmetry and development of lamina rotation in leaf primordia correlate with the taxo-nomic subdivision of the genus. Shoots of R. imeretinus are dorsiventral, with leaves arranged in four ranks, and lamina rotation occurs towards the upper side of the shoot. The sense of rotation of leaf primordia reverses with a periodicity of two plastochrons. In the abnormal shoot of Ulmus without lamina rotation, phyllotaxis was distichous and leaf primordia were symmetrical. The various cases are discussed in relation to the previously erected hypothesis that control of development in dorsiventral shoots with the rotated-lamina syndrome resides in alternating states of asymmetry in the shoot apex, and the corollary that a shoot with spiral phyllotaxis and one sense of lamina rotation should result if the state of asymmetry is maintained and does not alternate. Key words: Magnolia spp., Rhamnus imeretinus, Ulmus glabra, leaf, development, dorsiventrality, lamina rotation.

The rotated-lamina syndrome. V. Partial lamina rotation and related features in Hamamelidaceae

1994 ◽  
Vol 72 (5) ◽  
pp. 626-634 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Key Words ◽  
Shoot Apex ◽  
Leaf Development ◽  
Early Stage ◽  
Leaf Primordia ◽  
Leaf Base ◽  
Early Stages ◽  
Young Leaves

Shoots of Hamamelidaceae have been examined for the presence of the rotated-lamina syndrome, a condition in which young leaves in bud face towards one side of the shoot (normally the upper) rather than towards their own shoot apex. Early leaf development and bud organisation have been examined in representatives of eight genera with dorsiventral shoots and distichous phyllotaxis, and of four genera with radially symmetrical shoots and spiral or decussate phyllotaxis. Radially symmetrical shoots do not show any evidence of the syndrome. The distichous Corylopsis and Hamamelis species studied have leaf primordia that are asymmetrical from an early stage and show partial lamina rotation, the lamina facing obliquely towards the upper side of the bud. Mature laminae are usually asymmetrical. In Corylopsis rotation arises by torsion in the petiole region, and in Hamamelis by asymmetrical growth of the leaf base. Distichous examples without lamina rotation also have asymmetrical primordia in most cases, often have asymmetrical leaves, and all show the same asymmetrical development of the leaf base as found in Hamamelis. It is suggested that these features represent either (i) relics of rotated-lamina syndrome that was present in these cases but has been suppressed or (ii) early stages in evolution of rotated-lamina syndrome. It is suggested that suppression is the more likely interpretation. Corylopsis and Hamamelis may also be in the process of suppressing the syndrome. Key words: Hamamelidaceae, leaf, development, dorsiventrality, lamina rotation.

The rotated-lamina syndrome. II. The seedling of Ulmus glabra

1993 ◽  
Vol 71 (2) ◽  
pp. 222-228 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Key Words ◽  
Leaf Development ◽  
Growing Season ◽  
Radial Symmetry ◽  
Axillary Buds ◽  
Ulmus Glabra ◽  
Show Evidence ◽  
Seedling Leaf

Seedlings of Ulmus glabra show heteroblastic development of the plumular axis, involving a change from an initial radial symmetry with leaves in decussate pairs to dorsiventral symmetry with distichously arranged foliage leaves displaying the rotated-lamina syndrome. The change is very variable in detail. The change to distichy usually precedes the appearance of the rotated-lamina syndrome and is usually accompanied by the formation of one or more bud scales. Contrary to an earlier suggestion, there is no anisophyllous phase of development. Axillary buds in the radially symmetrical region of the seedling also show heteroblastic development but have distichous phyllotaxis from the beginning. During the first growing season they initiate a small number of bud scales and then a series of foliage leaves showing progressively accentuated development of the rotated-lamina syndrome. Some early foliage leaves show evidence of rotation of the lamina region by torsion. This is not detectable in later leaves in the seedling or in adult shoots, and it is suggested that the rotated-lamina syndrome may have arisen by heterochronic shift of the rotation process into progressively earlier stages of leaf development. Key words: Ulmus glabra, seedling, leaf, development, dorsiventrality.

The rotated-lamina syndrome. VI. The range from partial to near-complete rotation in Tiliaceae and Sterculiaceae

1997 ◽  
Vol 75 (1) ◽  
pp. 170-187 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Key Words ◽  
Shoot Apex ◽  
Leaf Development ◽  
Leaf Primordia

The rotated-lamina syndrome is a condition most commonly found in dorsiventral shoots with distichous phyllotaxis. Typically, young laminae in bud appear to be rotated to face towards the upper side of the shoot. The syndrome arises by asymmetrical growth from leaf primordia that initially face the shoot apex in approximately the normal way. It was previously described in Tilia. Further genera of Tiliaceae and the closely related Sterculiaceae were examined for the presence of the syndrome. Altogether it was found in 9 genera of the 30 examined. The syndrome is well developed in representatives of Commersonia, Corchorus, and Pterospermum, and less well developed in Luehia seemannii. Expression of the syndrome is minimal in Luehia divaricata, Theobroma, Byttneria, and Grewia. In all cases with distichous phyllotaxis that were examined in these families, the leaf primordia show at least some asymmetry in development and consequently there appears to be a predisposition to lamina rotation within the group. The syndrome is probably becoming suppressed in cases with minimal expression. The situation in dorsiventral shoots of Corchorus and Byttneria is complicated by the presence of inflorescences that arise in a leaf-opposed position. Key words: Sterculiaceae, Tiliaceae, leaf, development, dorsiventrality, lamina rotation.

The rotated-lamina syndrome. I. Ulmaceae

1993 ◽  
Vol 71 (2) ◽  
pp. 211-221 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Leaf Blade ◽  
Early Stage ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Foliage Leaf ◽  
Normal Orientation ◽  
Ulmus Glabra ◽  
Young Leaves ◽  
Final Orientation ◽  
Zelkova Serrata

In a number of plants, mostly woody, the components of the buds are arranged so that the laminae of the young leaves all face towards the same (upper) side of the bud, rather than towards the bud apex; in axillary buds they usually face towards the parent axis. This situation has been known for many years. For convenience, the general case is here called the rotated-lamina syndrome. There have been very few developmental investigations of how the laminae attain their unusual orientation, and these have come to different conclusions about cases in the Ulmaceae. This paper reports a detailed investigation of the syndrome in Ulmus glabra and Zelkova serrata, with comparative observations on other Ulmaceae, including cases in Celtis that do not exhibit the syndrome. The syndrome arises by different means in Ulmus and Zelkova. In Ulmus the leaf primordium is asymmetrical from the outset, the leaf blade region is obliquely dorsiventral from an early stage, and further asymmetrical growth of the leaf buttress rotates the whole leaf blade region into its final orientation as it develops. Individual shoots show heteroblastic development in progressing from bud scale to foliage leaf initiation, in increasing accentuation of the rotated-lamina syndrome, and in an increasing degree of dorsiventrality. In Zelkova, as previously described, the leaf blade region appears first as a radially symmetrical upgrowth, and it acquires dorsiventral symmetry directly in the rotated position. In Celtis spp. the lamina arises in a quite normal orientation, but reorients as it emerges from the bud. The leaf primordia of all species studied show asymmetry in other aspects, particularly in respect of stipule development, and these seem to be general features of the organisation of dorsiventral shoots. Key words: Ulmus, Zelkova, Celtis, leaf, development, dorsiventrality, lamina rotation.

In vitro morphogenesis in Osmunda cinnamomea. The role of the shoot apex in early leaf development

1969 ◽  
Vol 47 (4) ◽  
pp. 575-580 ◽  
Author(s):  
G. S. Hicks ◽  
T. A. Steeves
Keyword(s):  
Shoot Apex ◽  
Leaf Development ◽  
Leaf Primordia ◽  
Shoot Apices ◽  
In Vitro Morphogenesis ◽  
Indeterminate Growth ◽  
Nutrient Culture ◽  
Determinate Growth

In sterile nutrient culture, shoot apices of the rhizome of Osmunda cinnamomea L., devoid of all visible foliar primordia, quickly give rise to dorsiventral leaf primordia at a presumptive leaf site (I1). It was established that these primordia were irreversibly determined as leaves. To examine the morphogenetic role of the shoot apex in governing early leaf development, this site was permanently isolated from the shoot apex by a single tangential cut. Usually, radially symmetrical shoots of indeterminate growth arose at I1 as a result of this surgery. By contrast, when organic continuity between I1 and the shoot apex was only temporarily interrupted by a cut which was subsequently allowed to heal, normally oriented dorsiventral leaf primordia formed most frequently at I1. These, too, were determined as leaves. It was concluded that the shoot apex serves as a source of determinative influences for the nascent primordium, imposing dorsiventrality and a pattern of determinate growth on the leaf site.

scholarly journals Experiments on growth and inhibition. I.—The increase of inhibition with distance

1931 ◽  
Vol 108 (756) ◽  
pp. 209-223 ◽  
Keyword(s):  
Pisum Sativum ◽  
Axillary Buds ◽  
Axillary Bud ◽  
Inhibiting Effect ◽  
Different Ages ◽  
Young Leaves

Experiments were recently reported showing that, in young seedlings of Pisum sativum , the complete inhibiting effect which the shoot exerts upon its axillary buds comes entirely or almost entirely from three or four of its developing leave acting together (6). A single developing leaf was found usually to inhibit only partially—that is to say, sufficiently to delay the growth of an axillary bud below it, but not to check it completely. The strength of this partial inhibiting effect was measured by the retardation of the outgrowth of the axillary buds of the first or lowest leaf, as compared with their growth in completely defoliated controls. Comparisons were further made of the inhibiting effects of single young leaves of equal sizes near the apex in seedlings of different ages and heights, and it was found that in very young short seedlings the inhibiting effect was very slight or inappreciable, although in seedlings of a height of about 30 mm. or more (but still possessing well filled cotyledons) the effect was strong.

RECRUITMENT TO THE CIVIL SERVICE: AT THE LEGAL AND FACTUAL LEVELS

2020 ◽  
Vol 56 (07) ◽  
pp. 60-65
Author(s):  
Samira Eldar Mehraliyeva ◽  
Keyword(s):  
Key Words ◽  
Civil Service ◽  
Scientific Research ◽  
The State ◽  
Successful Implementation ◽  
Legal Basis ◽  
Constitutional Right ◽  
Service Legislation

The effective and successful implementation of the constitutional right of citizens to participate in the management of the state depends on the admission to the civil service. Admission to the civil service is one of the central issues of the civil service legislation. As the civil service is a relatively young and newly studied area in our legislation, there is a constant need for scientific research and suggestions for improvement in this area. The article reflects the legal and factual problems in this field, as a right to civil service, the conduct of competitions, the criteria for evaluating candidates. Key words: right of admission, organization of competitions, evaluation of the candidate, legal basis, actual problems

A fate map of the Arabidopsis embryonic shoot apical meristem

Development ◽  
1992 ◽  
Vol 115 (3) ◽  
pp. 745-753 ◽  
Author(s):  
V. F. Irish ◽  
I. M. Sussex
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Histological Analysis ◽  
Cell Number ◽  
Leaf Primordia ◽  
Axillary Buds ◽  
Fate Map ◽  
Seed Embryo ◽  
Sector Analysis ◽  
Pale Green

We have mapped the fate of cells in the Arabidopsis embryonic shoot apical meristem by irradiating seed and scoring the resulting clonally derived sectors. 176 white, yellow, pale green or variegated sectors were identified and scored for their position and extent in the resulting plants. Most sectors were confined to a fraction of a leaf, and only occasionally extended into the inflorescence. Sectors that extended into the inflorescence were larger, and usually encompassed about a third to a half of the inflorescence circumference. We also find that axillary buds in Arabidopsis are clonally related to the subtending leaf. Sections through the dry seed embryo indicate that the embryonic shoot apical meristem contains approximately 110 cells in the three meristematic layers prior to the formation of the first two leaf primordia. The histological analysis of cell number in the shoot apical meristem, in combination with the sector analysis have been used to construct a map of the probable fate of cells in the embryonic shoot apical meristem.

scholarly journals Sudden death associated with Niedenzuella stannea (Malpighiaceae) in cattle in the State of Mato Grosso, Brazil: importance and epidemiological aspects

2017 ◽  
Vol 37 (7) ◽  
pp. 662-666
Author(s):  
Flávio H.B. Caldeira ◽  
Geovanny B.G. Dias ◽  
Felipe P. de Arruda ◽  
Valdecy de M. Lourenço ◽  
Kalinne S. Bezerra ◽  
...  
Keyword(s):  
Sudden Death ◽  
Dry Season ◽  
The State ◽  
Acute Disease ◽  
Economic Losses ◽  
Control Methods ◽  
Mato Grosso ◽  
Araguaia River ◽  
Young Leaves ◽  
Plant Control

ABSTRACT: The aim of this study was to investigate the importance of an acute disease that was characterized by sudden death associated with exercise that affected cattle in the region of the Araguaia River, especially in the municipality of Torixoréu, southeastern Mato Grosso, Brazil. Between August and September 2013, eighty farms in the municipality were visited and the pastures of these farms were inspected. Epidemiological questionnaires were completed from 65 farms. A plant identified as Niedenzuella stannea (N. stannea) of the Malpighiaceae family was attributed to the cause of sudden death in cattle, what causes major economic losses. Sudden death reports have occurred since 1970, when livestock was introduced into the region, and sudden death reports still occur. Outbreaks were reported to occur from May to October, but mainly during the dry season between June and August. N. stannea was identified at 41 farms and was always found in near to rivers. The most effective plant control methods included plowing the pastures and fields followed by manual application of Tordon® (Picloram and 2.4D). The administration of 5g/kg of young leaves which were collected from a farm with a sudden death history in cattle also caused sudden death in a sheep. Thus, it is concluded that the sudden death of cattle in the region of the Araguaia River is caused by the consumption of N. stannea.

scholarly journals Asexual Propagation of Eggplant (Solanum melongena L.) through Encapsulated Axillary Buds

1970 ◽  
Vol 19 (2) ◽  
pp. 263-288 ◽  
Author(s):  
A.K.M. N. Huda ◽  
, M.A. Bari ◽  
M. Rahman
Keyword(s):  
Key Words ◽  
Plant Tissue ◽  
Short Communication ◽  
Solanum Melongena ◽  
Axillary Buds ◽  
Synthetic Seed ◽  
Asexual Propagation

 Key words: Auxillary buds, Eggplant, Encapsulation, Synthetic seed D.O.I. 10.3329/ptcb.v19i2.5445 Plant Tissue Cult. & Biotech. 19(2): 263-288, 2009 (December)       - Short communication

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