APICAL AND RADIAL GROWTH OF WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS) AT CHALK RIVER, ONTARIO, CANADA

1962 ◽  
Vol 40 (5) ◽  
pp. 659-668 ◽  
Author(s):  
D. A. Fraser
Keyword(s):  
Picea Glauca ◽  
Radial Growth ◽  
Central Zone ◽  
Peripheral Zone ◽  
Apical Growth ◽  
Female Cone ◽  
Developmental Anatomy ◽  
Terminal Bud ◽  
Vegetative And Reproductive Growth ◽  
Mother Cells

Apical and radial growth, and the developmental anatomy of vegetative and reproductive buds of Picea glauca, were investigated. Apical growth of the leader occurred from mid-May until mid-July, that of the side branches from mid-May until late June or early July. Total apical growth of the side branches, in general, diminished with their distance from the leader. Initiation of radial growth started in the main axis behind the terminal bud and moved basipetally along the trunk. Cessation of radial growth followed the same order.The apex of the vegetative bud developed in late July or early August includes a central zone, a peripheral zone with needle primordia, and a basal zone of thick-walled cells. Reproductive buds could be recognized by early August as oblong structures with globose appendages. By mid-August, these appendages had differentiated into either pollen sacs with pollen mother cells in the male buds, or into bracts and ovuliferous scales in the female ones. The female cone entered winter with little visible internal differentiation. The influence of temperature fluctuations on vegetative and reproductive growth is discussed.

VEGETATIVE AND REPRODUCTIVE GROWTH OF BLACK SPRUCE (PICEA MARIANA (MILL.) BSP.) AT CHALK RIVER, ONTARIO, CANADA

1966 ◽  
Vol 44 (5) ◽  
pp. 567-580 ◽  
Author(s):  
D. A. Fraser
Keyword(s):  
Black Spruce ◽  
Apical Growth ◽  
Radial Increment ◽  
Reproductive Growth ◽  
Developmental Anatomy ◽  
The Difference ◽  
Male Cones ◽  
Lateral Branches ◽  
Vegetative And Reproductive Growth ◽  
Pollen Sacs

Apical growth of the leader and lateral branches, as well as radial increment at the top and bottom of the trunk, were studied in two black spruce trees during 1960–63. The study complemented that of the developmental anatomy of shoot tips from adjacent trees during the period 1955–62. Time of initiation of apical growth varied from the third week of May in 1960, 1962, and 1963 to early June in 1961. The termination period of apical growth extended from early July in the lower branches, until about 2 weeks later in the upper branches and leader. Radial increment in the trunk started at about the same time as bud swelling and continued into August. A temporary mid-summer cessation of radial increment occurred at the top of the tree in two consecutive years. The response to artificially induced short and long days from May to August in 12-year-old saplings indicated that initiation of apical growth is not affected by photoperiod. Short days were associated with a reduction in apical extension, needle length, and growth period.Reproductive buds could be recognized by early August, but the formation of ovuliferous scales or pollen sacs did not occur until several weeks later. The male cones differentiated about 1 week before the female ones. The consistent production of flower buds in black spruce compared to the sporadic formation in white spruce is partly attributed to the difference in time of initiation of apical growth. In black spruce the development of buds occurs about 2 weeks later, usually during a warmer part of the summer when conditions are considered more conducive to reproductive growth.

GROWTH AND MORPHOGENESIS IN THE CANADIAN FOREST SPECIES: III. THE TIME SCALE OF MORPHOGENESIS AT THE STEM APEX OF PINUS RESINOSA AIT.

1958 ◽  
Vol 36 (5) ◽  
pp. 687-706 ◽  
Author(s):  
G. H. Duff ◽  
Norah J. Nolan
Keyword(s):  
Shoot Apex ◽  
Late Summer ◽  
Pinus Resinosa ◽  
Female Cone ◽  
Terminal Bud ◽  
Long Shoots ◽  
Short Shoots ◽  
Mother Cells ◽  
Autumn And Winter ◽  
Future Work

The main shoot apex of P. resinosa is found to comprise four groups of meristematic cells constituting four generative centers by which the parts of the winter terminal bud are laid down. These are the superficial initiating cells, the group or zone of subapical mother cells, the zone of pith mother cells, and the flanking cells.The superficial primordia of the terminal winter bud pass the winter as secondary lateral budlets on the flanks of the main bud axis. Those of the leaf-bearing short shoots do not normally differentiate leaves until the following spring. Neither do those which develop into lateral long shoots. The fertile budlets, on the contrary, produce cones in the late summer and autumn. The female cone enters the winter with no tissue differentiation of the cone body. This takes place very slowly but prominently in the course of the winter. The male inflorescence is well advanced in the autumn and winter progress is relatively slight.The natural control of morphogenesis at the shoot apex including the fitful seeding habit of P. resinosa is considered in the light of the growth timetable. To explain its mechanism, a working hypothesis involving production, consumption, and concentration of auxins is advanced as a preliminary to future work.

Regulation of cell reproduction in bud meristems of Tradescantia paludosa

1973 ◽  
Vol 51 (6) ◽  
pp. 1137-1145 ◽  
Author(s):  
Kyu-Byung Yun ◽  
J. M. Naylor
Keyword(s):  
Apical Dominance ◽  
Mitotic Cycle ◽  
Plant Cells ◽  
Central Zone ◽  
Apparent Absence ◽  
Cell Reproduction ◽  
Terminal Bud ◽  
Terminal Buds ◽  
Regulation Of Growth ◽  
Tradescantia Paludosa

The mitotic cycle can be arrested in the apical summit of vegetative terminal buds of Tradescantia paludosa by restricting the level of nitrogen or light available to the plant. Cells in this portion of the bud are much more sensitive to these stress conditions than those in the subjacent portion of the meristem. This differential response induced the establishment of a quiescent "central zone" which is distinguished from the rest of the meristem by the apparent absence of mitosis and DNA synthesis, larger nuclear volume, and a lower histone content of chromatin. These features are identical with those imposed by apical dominance in apices of inhibited lateral buds.The results support the view that competition for nutrients is an important causal factor in apical dominance. They suggest also that competition for nutrients within the terminal bud meristem is important in the regulation of growth in vegetative shoots in respones to conditions of the environment.

Radial Growth Decline of White Spruce (Picea glauca) During Hot Summers without Drought: Preliminary Results from a Study Site South of a Boreal Forest Border

2022 ◽  
Author(s):  
Andrei Lapenis ◽  
George Robinson ◽  
Gregory B. Lawrence
Keyword(s):  
New York ◽  
Boreal Forest ◽  
Picea Glauca ◽  
Radial Growth ◽  
Summer Precipitation ◽  
White Spruce ◽  
Southern Limit ◽  
Central New York ◽  
Growth Decline ◽  
Hot Days

Here we investigate the possible<sup></sup> future response of white spruce (Picea glauca) to a warmer climate by studying trees planted 90 years ago near the southern limit of their climate tolerance in central New York, 300 km south of the boreal forest where this species is prevalent. We employed high-frequency recording dendrometers to determine radial growth phenology of six mature white spruce trees during 2013-2017. Results demonstrate significant reductions in the length of radial growth periods inversely proportional to the number of hot days with air temperature exceeding 30 oC. During years with very hot summers, the start of radial growth began about 3 days earlier than the 2013-2017 average. However, in those same years the end of radial growth was also about 17 days earlier resulting in a shorter (70 versus 100 day), radial growth season. Abundant (350-500 mm) summer precipitation, which resulted in soil moisture values of 20-30% allowed us to dismiss drought as a factor. Instead, a likely cause of reduced radial growth was mean temperature that exceeded daily average of 30<sup> o</sup>C that lead to photoinhibition.

Three-Dimensional Analysis of Vestibular Efferent Neurons Innervating Semicircular Canals of the Gerbil

1997 ◽  
Vol 78 (6) ◽  
pp. 3234-3248 ◽  
Author(s):  
I. M. Purcell ◽  
A. A. Perachio
Keyword(s):  
Basement Membrane ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Central Zone ◽  
Semicircular Canals ◽  
Peripheral Zone ◽  
Longitudinal Axis ◽  
Open Loop ◽  
Response Dynamics ◽  
Efferent Neurons

Purcell, I. M. and A. A. Perachio. Three-dimensional analysis of vestibular efferent neurons innervating semicircular canals of the gerbil. J. Neurophysiol. 78: 3234–3248, 1997. Anterograde labeling techniques were used to examine peripheral innervation patterns of vestibular efferent neurons in the crista ampullares of the gerbil. Vestibular efferent neurons were labeled by extracellular injections of biocytin or biotinylated dextran amine into the contralateral or ipsilateral dorsal subgroup of efferent cell bodies (group e) located dorsolateral to the facial nerve genu. Anterogradely labeled efferent terminal field varicosities consist mainly of boutons en passant with fewer of the terminal type. The bouton swellings are located predominately in apposition to the basolateral borders of the afferent calyces and type II hair cells, but several boutons were identified close to the hair cell apical border on both types. Three-dimensional reconstruction and morphological analysis of the terminal fields from these cells located in the sensory neuroepithelium of the anterior, horizontal, and posterior cristae were performed. We show that efferent neurons densely innervate each end organ in widespread terminal fields. Subepithelial bifurcations of parent axons were minimal, with extensive collateralization occurring after the axons penetrated the basement membrane of the neuroepithelium. Axonal branching ranged between the 6th and 27th orders and terminal field collecting area far exceeds that of the peripheral terminals of primary afferent neurons. The terminal fields of the efferent neurons display three morphologically heterogeneous types: central, peripheral, and planum. All cell types possess terminal fields displaying a high degree of anisotropy with orientations typically parallel to or within ±45° of the longitudinal axis if the crista. Terminal fields of the central and planum zones predominately project medially toward the transverse axis from the more laterally located penetration of the basement membrane by the parent axon. Peripheral zone terminal fields extend predominately toward the planum semilunatum. The innervation areas of efferent terminal fields display a trend from smallest to largest for the central, peripheral, and planum types, respectively. Neurons that innervate the central zone of the crista do not extend into the peripheral or planum regions. Conversely, those neurons with terminal fields in the peripheral or planum regions do not innervate the central zone of the sensory neuroepithelium. The central zone of the crista is innervated preferentially by efferent neurons with cell bodies located in the ipsilateral group e. The peripheral and planum zones of the crista are innervated preferentially by efferent neurons with cell bodies located in the contralateral group e. A model incorporating our anatomic observations is presented describing an ipsilateral closed-loop feedback between ipsilateral efferent neurons and the periphery and an open-loop feed-forward innervation from contralateral efferent neurons. A possible role for the vestibular efferent neurons in the modulation of semicircular canal afferent response dynamics is proposed.

Sensorimotor Integration at the Dorsal Column Nuclei

Physiology ◽  
1999 ◽  
Vol 14 (6) ◽  
pp. 231-237
Author(s):  
Jorge Mariño ◽  
Luis Martinez ◽  
Antonio Canedo
Keyword(s):  
Sensorimotor Integration ◽  
Receptive Fields ◽  
Central Zone ◽  
Spatial Localization ◽  
Peripheral Zone ◽  
Dorsal Column ◽  
Primary Afferents ◽  
Zone Of Inhibition ◽  
Dorsal Column Nuclei ◽  
Recurrent Collaterals

Interaction among primary afferents, corticofugal fibers, and intrinsic elements allows for sensorimotor integration at the dorsal column nuclei. The interneurons permit the spatial localization, the recurrent collaterals synchronize the activity of projecting cells with overlapping receptive fields, and the corticofugal fibers induce a central zone of activity surrounded by a peripheral zone of inhibition.

Within-tree patterns of wood stiffness for white spruce (Picea glauca) and trembling aspen (Populus tremuloides)

2014 ◽  
Vol 44 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Derek F. Sattler ◽  
Philip G. Comeau ◽  
Alexis Achim
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Radial Growth ◽  
Tree Height ◽  
White Spruce ◽  
Vertical Position ◽  
Trembling Aspen ◽  
Mixed Effect ◽  
Cambial Age ◽  
Rate Of Increase

Radial patterns of modulus of elasticity (MOE) were examined for white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to (1) evaluate the relationship between pith-to-bark changes in MOE and cambial age or distance from pith; (2) develop species-specific models to predict pith-to-bark changes in MOE; and (3) to test the influences of radial growth, relative vertical height, and tree slenderness (tree height/DBH) on MOE. For both species, cambial age was selected as the best explanatory variable with which to build pith-to-bark models of MOE. For white spruce and trembling aspen, the final nonlinear mixed-effect models indicated that an augmented rate of increase in MOE occurred with increasing vertical position within the tree. For white spruce trees, radial growth and slenderness were found to positively influence maximum estimated MOE. For trembling aspen, there was no apparent effect of vertical position or radial growth on maximum MOE. The results shed light on potential drivers of radial patterns of MOE and will be useful in guiding silvicultural prescriptions.

scholarly journals Computed Tomography Perfusion, Magnetic Resonance Imaging, and Histopathological Findings After Laparoscopic Renal Cryoablation: An In Vivo Pig Model

2016 ◽  
Vol 16 (4) ◽  
pp. 406-413 ◽  
Author(s):  
Tommy Kjærgaard Nielsen ◽  
Øyvind Østraat ◽  
Ole Graumann ◽  
Bodil Ginnerup Pedersen ◽  
Gratien Andersen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Central Zone ◽  
Peripheral Zone ◽  
Scar Tissue ◽  
Resonance Imaging ◽  
Computed Tomography Perfusion ◽  
Laparoscopic Assisted

The present study investigates how computed tomography perfusion scans and magnetic resonance imaging correlates with the histopathological alterations in renal tissue after cryoablation. A total of 15 pigs were subjected to laparoscopic-assisted cryoablation on both kidneys. After intervention, each animal was randomized to a postoperative follow-up period of 1, 2, or 4 weeks, after which computed tomography perfusion and magnetic resonance imaging scans were performed. Immediately after imaging, open bilateral nephrectomy was performed allowing for histopathological examination of the cryolesions. On computed tomography perfusion and magnetic resonance imaging examinations, rim enhancement was observed in the transition zone of the cryolesion 1week after laparoscopic-assisted cryoablation. This rim enhancement was found to subside after 2 and 4 weeks of follow-up, which was consistent with the microscopic examinations revealing of fibrotic scar tissue formation in the peripheral zone of the cryolesion. On T2 magnetic resonance imaging sequences, a thin hypointense rim surrounded the cryolesion, separating it from the adjacent renal parenchyma. Microscopic examinations revealed hemorrhage and later hemosiderin located in the peripheral zone. No nodular or diffuse contrast enhancement was found in the central zone of the cryolesions at any follow-up stage on neither computed tomography perfusion nor magnetic resonance imaging. On microscopic examinations, the central zone was found to consist of coagulative necrosis 1 week after laparoscopic-assisted cryoablation, which was partially replaced by fibrotic scar tissue 4 weeks following laparoscopic-assisted cryoablation. Both computed tomography perfusion and magnetic resonance imaging found the renal collecting system to be involved at all 3 stages of follow-up, but on microscopic examination, the urothelium was found to be intact in all cases. In conclusion, cryoablation effectively destroyed renal parenchyma, leaving the urothelium intact. Both computed tomography perfusion and magnetic resonance imaging reflect the microscopic findings but with some differences, especially regarding the peripheral zone. Magnetic resonance imaging seems an attractive modality for early postoperative follow-up.

Further analytical and experimental studies on the shoot apex of Helianthus annuus: variable activity in the central zone

1979 ◽  
Vol 57 (8) ◽  
pp. 971-980 ◽  
Author(s):  
E. L. Davis ◽  
Patricia Rennie ◽  
Taylor A. Steeves
Keyword(s):  
Helianthus Annuus ◽  
Mitotic Activity ◽  
Shoot Apex ◽  
Experimental Studies ◽  
Central Zone ◽  
Peripheral Zone ◽  
Intact Plants ◽  
Cast Doubt ◽  
Young Leaves ◽  
Mitotic Frequency

The cytologically distinctive central zone of the vegetative shoot apex of Helianthus annuus L. cv. Peredovic has a mitotic frequency considerably lower than that of the surrounding peripheral zone in intact plants. Apices excised and grown in culture for 5 days before being supplied with [H3]thymidine reveal a correspondingly low level of DNA synthesis in the central zone when autoradiographed. In similarly cultured apices, mitotic activity in the central zone is less than that recorded for intact plants. Labelling immediately after excision of the apex indicates that the central zone cells are activated by the operation and quiescence returns during the following 5 days. This activation is confirmed by mitotic counts 2 days after excision. The removal of only two young leaves from the apical buds of otherwise intact plants results in a comparable stimulation of mitotic activity in the central zone. These observations cast doubt upon the significance of mitotic activity in living shoot apices when these have been exposed for observation by removal of leaves. They also raise questions about the validity of labelling techniques which involve the partial dissection of the shoot apex.

scholarly journals Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss) †

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 589 ◽  
Author(s):  
Cyriac S. Mvolo ◽  
Ahmed Koubaa ◽  
Jean Beaulieu ◽  
Alain Cloutier ◽  
Maurice Defo ◽  
...  
Keyword(s):  
Physical Properties ◽  
Picea Glauca ◽  
Radial Growth ◽  
Juvenile Wood ◽  
Wood Properties ◽  
Mature Wood ◽  
Ring Density ◽  
Tracheid Length ◽  
Latewood Density ◽  
Anatomical Properties

We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce (Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal component analysis (PCA) was used to establish if all of the properties must be measured and to determine the key properties that can be used as proxies for the other variables. Radial growth-related and physical properties were measured with an X-ray densitometer, while anatomical properties were measured with a Fiber Quality Analyzer. Fifteen wood properties (tracheid length (TL) and diameter (TD), earlywood tracheid length (ETL) and diameter (ETD), latewood tracheid length (LTL) and diameter (LTD), ring width (RW), ring area (RA), earlywood width (EWW), latewood width (LWW), latewood proportion (LWP), ring density (RD), intra-ring density variation, earlywood density (EWD), and latewood density (LWD)) were assessed. Relationships were evaluated at intra-ring and inter-ring levels in the juvenile wood (JW) and mature wood (MW) zones. Except for a few cases when mature tracheid diameter (TD) was involved, all intra-ring anatomical properties were highly and significantly correlated. Radial growth properties were correlated, with stronger relationships in MW compared to JW. Physical properties were often positively and significantly correlated in both JW and MW. A higher earlywood density coupled with a lower latewood density favored wood uniformity, i.e., the homogeneity of ring density within a growth ring. Managing plantations to suppress trees growth during JW formation, and enhancing radial growth when MW formation starts will favor overall wood quality. In order, RW-EWW-RA, TL-ETL-LTL, and RD-EWD-LWP are the three clusters that appeared in the three wood zones, the whole pith-to-bark radial section, the juvenile wood zone, and the mature wood zone.

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