Leader size and number of leaf primordia as factors in timing of terminal bud flush in black spruce and tamarack

1987 ◽  
Vol 17 (11) ◽  
pp. 1390-1393
Author(s):  
V. J. Lieffers
Keyword(s):  
Black Spruce ◽  
Leaf Primordia ◽  
North Central ◽  
Large Numbers ◽  
Terminal Bud ◽  
Final Length ◽  
Bud Growth ◽  
Terminal Buds ◽  
Individual Trees

Black spruce (Piceamariana (Mill.) B.S.P.) and tamarack (Larixlaricina (Du Roi) K. Koch) in a peatland in north central Alberta were examined twice weekly for terminal bud flush, length of leader, and cessation of leader elongation. Time of terminal bud flush of black spruce, which has determinate bud growth, was negatively correlated with the final length of leader. Differences in timing of flush of terminal buds of individual trees between 1984 and 1985 were negatively related to the ratio of leader length in 1984 to that in 1985. It is proposed that part of the variability in time of bud flush is related to the number of leaf primordia in the expanding bud. Buds with large numbers of leaf primordia flushed earlier than buds with few primordia. Time of terminal bud flush of tamarack, which has indeterminate bud growth, was poorly correlated with the final length of leader.

Freezing temperatures and exposure times during bud break and shoot elongation influence survival and growth of containerized black spruce (Piceamariana) seedlings

1996 ◽  
Vol 26 (8) ◽  
pp. 1481-1489 ◽  
Author(s):  
Francine J. Bigras ◽  
Carole Hébert
Keyword(s):  
Black Spruce ◽  
Seedling Survival ◽  
Shoot Elongation ◽  
Bud Break ◽  
Significant Damage ◽  
Terminal Bud ◽  
Survival And Growth ◽  
Freezing Temperatures ◽  
Terminal Buds ◽  
Spring Frosts

Spring frosts frequently cause significant damage to conifer seedlings during bud flushing and shoot elongation in forestry nurseries. To insure adequate protection, levels of frost sensitivity must be known during these stages of development. Eight- or 9-month-old containerized black spruce seedlings (Piceamariana (Mill.) BSP) were submitted to freezing temperatures of 0° to −10 °C for 1–6 h at the following stages: (1) nonswollen terminal buds, (2) swollen terminal buds, (3) terminal bud scales bursting, needle tips emerging, and (4) shoots elongating, 1−5 cm. After freezing, seedlings were grown for 130 days in a greenhouse. Seedling survival was estimated; dead seedlings discarded; and damage to buds, needles, and roots as well as diameter and shoot increment were measured on the remaining seedlings. Frost sensitivity increased as buds flushed and new shoots elongated. Decreased seedling and bud survival was noted with increasing time of freezing exposure and decreasing temperature in stages 2, 3, and 4. Damage to needles and roots increases, while diameter decreases, with decreasing temperatures at all stages; however, shoot increment was influenced by decreasing temperatures only at stages 2 and 3.

Effects of drainage on substrate temperature and phenology of some trees and shrubs in an Alberta peatland

1987 ◽  
Vol 17 (2) ◽  
pp. 97-104 ◽  
Author(s):  
V. J. Lieffers ◽  
R. L. Rothwell
Keyword(s):  
Water Table ◽  
Black Spruce ◽  
North Central ◽  
Air Temperatures ◽  
Dwarf Birch ◽  
Summer Temperatures ◽  
The Mean ◽  
Study Sites ◽  
Individual Trees ◽  
Trees And Shrubs

A 50-ha portion of an intermediate fen in north central Alberta was drained in 1984. Study sites were established in the drained area and in an adjacent undrained area. In each site, seasonal water table depth and substrate and air temperatures were monitored. The drainage lowered the water table from 20 to 50 cm compared with the adjacent undrained site. Substrate of the drained area warmed above 0 °C slightly later than the undrained area but maximum summer temperatures were higher in the drained site. Temperatures in 1985 at the 10-cm depth of the drained site peaked in early August at 15–16 °C, 3–4 °C higher than the undrained site. Forty-five black spruce (Piceamariana (Mill.) B.S.P.), 45 tamarack (Larixlaricina (Du Roi) K. Koch), and 25 dwarf birch (Betulapumila L.) were tagged and examined twice weekly. For tamarack and dwarf birch, flowering and bud flush were significantly earlier by 2–6 days in the drained site. For black spruce, flowering was earlier in the drained site; bud flush, however, was earlier in the undrained site in 1985 but there were no differences between sites in 1986. For both black spruce and tamarack, the mean date at which individual trees reached 50% of total leader elongation was earlier in the drained site in both 1984 and 1985.

Structure and development of terminal bud scales in green ash

1990 ◽  
Vol 68 (1) ◽  
pp. 12-20 ◽  
Author(s):  
E. K. Merrill
Keyword(s):  
Developmental Stages ◽  
Early Summer ◽  
Leaf Primordia ◽  
Apical Region ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Foliage Leaf ◽  
Terminal Bud ◽  
Terminal Buds ◽  
Early Developmental

Structure and development of terminal bud scales of green ash (Fraxinus pennsylvanica var. subintegerrima) were studied to provide a basis for comparison with foliage leaves of the same species. To identify early developmental stages of bud scales, structure and phenology of terminal buds were investigated first. Overwintering terminal buds have typically three or four pairs of bud scales and three to six pairs of foliage leaf primordia. Bud scales have a flattened base topped by rudimentary leaflets. After bud break, the first leaf primordia that are initiated develop and mature into terminal bud scales by early summer. Although morphology and anatomy of mature foliage leaves and bud scales are very different, primordia of leaf forms are similar until they reach a length of 500 μm. At that length both leaf forms have a base and apical leaflets. Bud scale bases widen and elongate without much thickening, while growth in the apical region is restricted. Marginal growth of the bud scale base is different from that described for most leaf blades. Terminal bud scales could be interpreted as being ontogenetically derived from foliage leaf primordia.

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.

Clonal and nonclonal genetic structure of subarctic black spruce (Picea mariana) populations in Yukon territory

Botany ◽  
2011 ◽  
Vol 89 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Marios Viktora ◽  
Rodney A. Savidge ◽  
Om P. Rajora
Keyword(s):  
Genetic Structure ◽  
Picea Mariana ◽  
Black Spruce ◽  
A Priori ◽  
Nuclear Genome ◽  
Yukon Territory ◽  
Fire Disturbance ◽  
Clone Size ◽  
Flat Terrain ◽  
Individual Trees

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.

scholarly journals A Range Extension for the Rock Vole, Microtus chrotorrhinus, in Labrador

2005 ◽  
Vol 119 (3) ◽  
pp. 412 ◽  
Author(s):  
Sarah W. Lansing
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Range Extension ◽  
Southern Coast ◽  
Central Coast ◽  
North Central ◽  
The North ◽  
Southern Island

Rock Voles (Microtus chrotorrhinus) were previously documented only from the southern coast of Labrador and the Strait of Belle Isle south of Hamilton Inlet. During two field seasons in 2000 and 2001, both in July, six Rock Vole specimens were collected on Southern Island, off the north-central coast of Labrador, extending the range of the subspecies Microtus chrotorrhinus ravus approximately 250 km to the central Labrador coast north of Hamilton Inlet. Rock Voles were trapped primarily in stunted Black Spruce (Picea mariana) forest and areas associated with rocks, thick brush, and water.

Alternate Strip Clearcutting in Upland Black Spruce: VIII. Shallow-soil Ecosystems and Their Classification

1988 ◽  
Vol 64 (1) ◽  
pp. 70-75 ◽  
Author(s):  
Richard A. Sims ◽  
William D. Towill
Keyword(s):  
Black Spruce ◽  
Mineral Soil ◽  
Fragile Sites ◽  
Soil Types ◽  
Northern Ontario ◽  
North Central ◽  
The North ◽  
Shallow Soil ◽  
Soil Ecosystems ◽  
Shallow Soils

Shallow-soil sites in the Nipigon-Beardmore area of northern Ontario are widespread and pose unique operational problems for forest managers. Several working definitions of shallow soils are used in Ontario. More accurate regional definitions are required in order that silvicultural decisions for these sometimes fragile sites may be refined or new ones developed. Harvesting and silvicultural options for shallow-soil sites are limited in the North Central Region.A program of Forest Ecosystem Classification (FEC) for the North Central Region has been designed to provide better understanding of shallow sites and a framework of standardized definitions. The FEC describes several shallow-soil types that occur over boulder pavement or bedrock, and differentiates mainly on the basis of depth-to-rock contact, surface organic material thickness and texture of the primary mineral soil particles. Operational application of this classification may require identification of complexes of shallow-soil types.

scholarly journals Exogenous Cytokinin Induces “Out of Season” Flowering in Protea cv. Carnival

2009 ◽  
Vol 134 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Eleanor W. Hoffman ◽  
Dirk U. Bellstedt ◽  
Gerard Jacobs
Keyword(s):  
Flowering Time ◽  
Southern Hemisphere ◽  
Shoot Growth ◽  
Xylem Sap ◽  
Development Stage ◽  
Green Point ◽  
Terminal Bud ◽  
Exogenous Cytokinin ◽  
Terminal Buds ◽  
Early Phases

The cytokinin concentration in the xylem sap of Protea L. cv. Carnival (Protea compacta R. Br. × Protea neriifolia R. Br.) shoots was determined at regular intervals from 11 weeks before until 10 weeks after spring budbreak. Cytokinin levels were high during the early phases of spring shoot growth. Benzyladenine (BA) at 50, 250, or 500 mg·L−1 was applied to entire shoots on 22 Feb., 12 Apr., and 22 May 2001 (fall in the southern hemisphere) or only to terminal buds on 22 May 2001 at 500 mg·L−1. Most of the terminal buds sprouted and initiated an inflorescence when BA application at 500 mg·L−1 in May was directed only to terminal buds, whereas lower flowering percentages (0%–35%) were achieved when the entire shoot was treated. After whole shoots were treated with BA in Apr. 2001, between 5% and 45% floral reversion was observed. High flowering percentages of 87% to 93% were recorded when BA was applied at 500 mg·L−1 to the terminal bud in the dormant state or up to the stage when sprouting buds reached the green point development stage. Later applications were less effective, inducing 42% to 43% inflorescence initiation. The flowering time of BA-induced inflorescences was advanced by more than 2 months compared with flowers that initiated naturally on the spring flush.

Efficiency of night interruption treatments with red and far-red light-emitting diodes (LEDs) in preventing bud set in Norway spruce seedlings

2018 ◽  
Vol 48 (9) ◽  
pp. 1001-1006 ◽  
Author(s):  
Johanna Riikonen
Keyword(s):  
Norway Spruce ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Growth Conditions ◽  
Early Spring ◽  
Light Emitting ◽  
Bud Set ◽  
Terminal Bud ◽  
Natural Photoperiod ◽  
Terminal Buds

Terminal bud set can be prevented by interrupting night with short pulses of light when the natural photoperiod is too short to maintain growth. Norway spruce (Picea abies Karst.) seedlings originating from 61°N and 64°N were grown in growth chambers under conditions that mimic growth conditions in a heated greenhouse in early spring in Finland (experiment 1) or under constant growth conditions (experiment 2). The seedlings were exposed to the following night interruption (NI) treatments using light-emitting diodes (LEDs) that generated red (R, peak at 660 nm) and far-red (FR, peak at 735 nm) wavelengths in 20 s pulses at 15 min intervals: (i) red light alone (R); (ii) R combined with FR (R + FR); and (iii) control (no NI treatment). The R + FR treatment was more effective in preventing terminal bud set than the R treatment. Seedling responses depended on the provenance and growth conditions. The R treatment reduced the proportion of seedlings with terminal buds in the 61°N seedlings and delayed bud set in the 64°N seedlings. The fluctuating growth conditions or longer dark period between the photoperiod and NI treatments reduced the efficiency of the R + FR treatment. A combination of R and FR LEDs with adequate light intensity and duration is suitable for intermittent NI treatment in Norway spruce seedlings.

Precipitation nutrients in the open and under two forests in Minnesota

1977 ◽  
Vol 7 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Elon S. Verry ◽  
D. R. Timmons
Keyword(s):  
Forest Floor ◽  
Black Spruce ◽  
Inorganic Nitrogen ◽  
Annual Precipitation ◽  
Nutrient Inputs ◽  
Nutrient Input ◽  
Forest Canopies ◽  
North Central ◽  
Annual Amount ◽  
Total P

Concentrations of N, P, K, Ca, Mg, and Na were measured in rain and snow in the open, and in throughfall and stemflow under black spruce and aspen forests in north-central Minnesota. Concentrations of total P in rain and black spruce throughfall were inversely related to storm size. Annual precipitation nutrient inputs to the forest floor were calculated for each site. In general, nutrient contributions from snow were less than 10% of the annual nutrient input from precipitation at each site, and differences in snow nutrient input between sites were minimal. Rainfall nutrient input differed significantly between sites. Rain and snow passing through both forest canopies were enriched with nutrients except inorganic nitrogen. Total annual nutrients added to the forest floor under the black spruce stand averaged 1.7 times that added in the open; the annual amount added under the aspen stand averaged 5.2 times that added in the open.

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