Occurrence and distribution of cones borne laterally on long shoots of Larix laricina

1984 ◽  
Vol 62 (4) ◽  
pp. 771-777 ◽  
Author(s):  
G. R. Powell ◽  
Kathleen J. Tosh ◽  
W. R. Remphrey
Keyword(s):  
Larix Laricina ◽  
Short Shoot ◽  
Shoot Buds ◽  
First Order ◽  
Long Shoots ◽  
Short Shoots

Trees of Larix laricina (Du Roi) K. Koch reaching the stage of first cone bearing tended to produce the majority of their seed cones, and many of their pollen cones, in lateral (axillary) positions along long shoots. In subsequent cone bearing, a greater proportion of the cones occurred in the typical (for the genus) position terminating short shoots. Some trees 2 to 4 m tall bore over 500 lateral seed cones. Lateral cones occurred on all kinds of long shoots, except sylleptic first-order shoots, produced in the 3-year-old portion of the crown. Lateral seed cones were borne on the morphogenically proximal halves of the long shoots and on all surfaces around the circumference of the shoots, but they were less frequent on upper surfaces than on other surfaces. Lateral pollen cones occurred in the proximal 10% of the lengths of the bearing shoots and were restricted to the undersurfaces or sides of the shoots. Lateral cone buds were distinctively larger and contained more bud scales than adjacent lateral short-shoot buds.

Crown architecture of Larix laricina saplings: production and disposition of foliage and their simulation

1988 ◽  
Vol 66 (11) ◽  
pp. 2234-2246 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell
Keyword(s):  
Simulation Models ◽  
Larix Laricina ◽  
Short Shoot ◽  
First Order ◽  
Growth Increments ◽  
Rate Of Increase ◽  
Long Shoots ◽  
Short Shoots ◽  
Successive Generations ◽  
The Relationship

In saplings of Larix laricina (Du Roi) K. Koch (tamarack), correlations between projected leaf area (PLA) and architectural variables such as shoot length and shoot age were incorporated into existing simulation models to estimate the distribution of PLA in the crown according to several spatial, temporal, and morphological parameters. After five generations of simulated shoot growth, PLA values ranged from 8.2 m2 for trees with short height growth increments (HGIs) and no syllepsis to 25.5 m2 for those with long HGIs and heavy syllepsis. Although PLA increased, the rate of increase declined over time. In early simulated generations, long-shoot PLA predominated. In the fifth simulated generation, short shoots bore about 75% of the PLA. There was a basipetal increase in PLA by HGI, but the relationship was nonlinear. In trees with syllepsis, sylleptic origin branches on individual HGIs carried more PLA than concomitant proleptic branches for 1 year but thereafter the proportions were reversed. Over successive generations, the contribution of different branch orders to the total PLA shifted from mostly first-order long shoots (including PLA on daughter short-shoot axes) to second-order shoots carrying more than 50% by year 5. Because of the short-shoot contribution, there was considerable PLA in all regions of the crown, although the greatest concentration was in lower regions of midconic zones. Simulated PLA index increased substantially with crown development. Trees with short HGIs had the greatest PLA index and those with long HGIs had the least.

Crown architecture of Larix laricina saplings: an analysis of higher order branching

1987 ◽  
Vol 65 (2) ◽  
pp. 268-279 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell
Keyword(s):  
Simulation Modelling ◽  
Shoot Length ◽  
Larix Laricina ◽  
Structural Development ◽  
Short Shoot ◽  
Lateral Buds ◽  
Architectural Patterns ◽  
Long Shoots ◽  
Short Shoots ◽  
Terminal Shoot

Quantitative analysis and simulation modelling of Larix laricina (Du Roi) K. Koch branches revealed a complex system of architectural patterns and correlations. Numbers of lateral buds and long shoots were positively correlated with parent-shoot length, but the relationships varied among shoot orders and for sylleptic shoots. For order 2 and sylleptic shoots, numbers of lateral long shoots were also correlated with associated terminal-shoot lengths. Sylleptic shoots produced more lateral long shoots than equivalent proleptic shoots. Lateral long-shoot lengths decreased basipetally and were correlated with terminal-shoot lengths. Lengths of order 2 lateral long shoots also varied independently with crown position. Generally, the degree of apical control decreased and the proportion of short shoots increased with positions of less vigour in the crown. Terminal long-shoot lengths varied with parent-shoot length, location, and to some extent parent-axis leader length. Terminal short-shoot production was associated with shorter parent shoots. Shorter order 2 shoots (<60 mm) and most order 3 shoots produced no lateral long shoots. The net result was that branch structural development ceased in less vigorous crown positions. The spatial disposition of shoots, as defined by elevation and divergence angles, varied with position of origin around and along parent shoots. Although variable, elevation angles decreased and divergence angles increased basipetally.

Crown architecture of Larix laricina saplings: shoot preformation and neoformation and their relationships to shoot vigour

1984 ◽  
Vol 62 (11) ◽  
pp. 2181-2192 ◽  
Author(s):  
W. R. Remphrey ◽  
G. R. Powell
Keyword(s):  
Leaf Primordia ◽  
Shoot Length ◽  
Larix Laricina ◽  
Crown Architecture ◽  
Short Shoot ◽  
Shoot Buds ◽  
Lateral Buds ◽  
Lateral Bud ◽  
Long Shoots ◽  
Terminal Buds

Resting buds from five locations on long shoots in each of six crown positions were compared for 30 Larix laricina (Du Roi) K. Koch saplings. At each locus, bud sizes, numbers of bud scales and preformed leaf primordia (basal and axial for long-shoot buds), and apical widths were positively related to parent-shoot length. Along individual shoots, (i) terminal and lateral long-shoot buds contained fewer basal-leaf primordia than the more proximal short-shoot buds; (ii) terminal buds contained the most bud scales and axial-leaf primordia; and (iii) numbers of bud scales increased, while numbers of axial-leaf primordia generally decreased, basipetally among lateral buds. Comparison of bud leaf content with leaves on elongated shoots by regression showed that numbers of preformed and neoformed leaves increased with shoot length, but numbers of neoformed leaves did so to a greater degree. Internode lengths, numbers of leaves per lateral bud produced, and leaf lengths were greater on neoformed than on preformed shoot segments. Because of their capacity for neoformed growth following preformed growth and because of increases in internode lengths among all axial leaves, shoots from subjacent lateral buds replaced experimentally decapitated tree leaders (terminal buds) in one season, with little or no loss of height growth.

SEASONAL GROWTH CHARACTERISTICS OF LONG AND SHORT SHOOTS OF TAMARACK

1967 ◽  
Vol 45 (9) ◽  
pp. 1643-1651 ◽  
Author(s):  
J. Johanna Clausen ◽  
T. T. Kozlowski
Keyword(s):  
Seasonal Changes ◽  
Stem Elongation ◽  
Growth Characteristics ◽  
Weight Increase ◽  
Stem Length ◽  
Larix Laricina ◽  
Seasonal Growth ◽  
Long Shoots ◽  
Short Shoots ◽  
Food Reserves

Tamarack (Larix laricina (DuRoi) K. Koch) produces long shoots which bear two kinds of needles. Early needles are present in the bud and elongate rapidly after budbreak. Late needles, few of which are present in the bud, elongate later than early needles. Short shoots bear early needles only, and stem length seldom exceeds 1 mm. Seasonal changes in length and weight of needles and stems of both shoot types were measured. In long shoots, 75% of stem elongation, more than 70% of stem weight increment, and 65–70% of late needle elongation occurred after early needles were full-sized. Stem and late needle elongation ceased simultaneously, after which time needle weight decreased and stem weight increased. Early needles probably drew on food reserves while developing, and then themselves contributed to stem and late needle elongation. Final stem weight increase probably used photosynthate from both late and early needles of the current year.Shading of current and last year's needles showed that shoots in which photosynthesis was interrupted in this way produced shorter, lighter-weight stems than did control shoots.

Leaf area development on different shoot types in a young aspen stand and its effect upon production

1970 ◽  
Vol 48 (10) ◽  
pp. 1801-1804 ◽  
Author(s):  
D. F. W. Pollard
Keyword(s):  
Leaf Area ◽  
Total Production ◽  
Short Shoot ◽  
Area Index ◽  
Young Leaves ◽  
Long Shoots ◽  
Short Shoots ◽  
Area Development ◽  
Leaf Area Development ◽  
Photosynthetic Efficiencies

Different shoot types in aspen crowns carried leaves of different ages; leaders continued to produce leaves until early August and always carried some young leaves, whereas short shoots completed development by mid-June. Development of foliage on long shoots was intermediate between that on leaders and short shoots. Leaf area index of the 6-year-old stand reached a maximum of 2.4, of which 2.1 was contributed by short-shoot foliage. The rest was formed by leaders and long shoots. Young leaves on leaders and long shoots were not sufficient to influence total production in the stand appreciably, even though young aspen leaves may have high photosynthetic efficiencies. These young leaves could, however, influence height growth and lateral development of the canopy.

Shoot type demography and dry matter partitioning: a morphometric approach in apple (Malus ×domestica)

2001 ◽  
Vol 79 (11) ◽  
pp. 1270-1273 ◽  
Author(s):  
Pierre-Éric Lauri ◽  
Jean-Jacques Kelner
Keyword(s):  
Leaf Area ◽  
Malus Domestica ◽  
Detrimental Effect ◽  
Canopy Structure ◽  
Short Shoot ◽  
Dry Matter Partitioning ◽  
Fruiting Branch ◽  
Long Shoots ◽  
Short Shoots ◽  
Time Required

In a study of the apple (Malus ×domestica Borkh.) canopy structure, 5-year-old 'Fuji' and 'Braeburn' trees grafted on a low-vigour rootstock (M9) were compared at both fruiting branch and shoot levels. Percentages of short ([Formula: see text]5 cm) shoots and short shoot leaf area were significantly higher on 'Braeburn' than on 'Fuji', (76.8% vs. 72.6% and 46.9% vs. 42.9% for 'Braeburn' and 'Fuji', respectively). This high percentage of short shoots as compared with literature data was probably due to the training method, which reduced vigour. At shoot level, the ratio between dry masses of axis and leaf, called the axialization index, was determined to compare short and long shoots. Axialization values were higher for 'Braeburn' than for 'Fuji'. Although overall and individual leaf area was greater on long shoots, long shoot axialization (0.64 and 0.54 for 'Braeburn' and 'Fuji', respectively) was approximately twice that of short shoots (0.36 and 0.24, respectively). Therefore, for short shoots, the reduced carbon investment in supporting tissues may explain the significant role short shoots played in supporting early fruit development. For long shoots, the longer time required to reach the autotrophic and then exporting stage as well as the detrimental effect of early extension shoot development on fruit set might be explained by greater axialization.Key words: long shoot, short shoot, axialization index, apple, Malus ×domestica, biomass partitioning.

Shoot development in Betula papyrifera. I. Short-shoot organogenesis

1983 ◽  
Vol 61 (12) ◽  
pp. 3049-3065 ◽  
Author(s):  
Alastair D. Macdonald ◽  
D. H. Mothersill
Keyword(s):  
Axillary Buds ◽  
Axillary Bud ◽  
Bud Burst ◽  
Betula Papyrifera ◽  
Short Shoot ◽  
Mature Trees ◽  
Shoot Buds ◽  
Female Inflorescence ◽  
Terminal Bud ◽  
Short Shoots

Buds and developing branches of Betula papyrifera were collected weekly from mature trees during three successive growing seasons. Material was prepared to show stages of bud inception, development, and flushing and female inflorescence inception. Short shoots develop from (i) proximal axillary buds on long shoots (ii) short-shoot terminal buds, or (iii) axillary buds on flowering short shoots. An axillary bud apex forms a terminal bud after bud burst. An axillary bud possesses one outer rudimentary leaf, but all other short-shoot buds have three outer rudimentary leaves. All short-shoot buds possess, in addition, one–three embryonic foliage leaves and, distally, three primordial rudimentary leaves which form the outermost appendages of the succeeding terminal bud. Rudimentary leaf stipules form the cataphylls. Foliage leaf primordia are initiated in May – early June and rudimentary leaves arise in late June – July. If a bud apex is initiated in year n, female inflorescence induction occurs in late June of year n + 1 or any succeeding year. An axillary bud develops on a short shoot as a consequence of flowering; it is initiated concurrently with inflorescence development and its development is completed during flowering and seed maturation. Short- and long-shoot buds can be distinguished, upon dissection, in mid-July when buds are forming. Hence, determination of potential long and short shoots occurs the year before bud burst.

Shoot development in Betula papyrifera. IV. Comparisons between growth characteristics and expression of vegetative long and short shoots

1984 ◽  
Vol 62 (3) ◽  
pp. 446-453 ◽  
Author(s):  
J. Cartey Caesar ◽  
Alastair D. Macdonald
Keyword(s):  
Growth Rates ◽  
Stem Elongation ◽  
Morphological Characteristics ◽  
Axillary Buds ◽  
Betula Papyrifera ◽  
Short Shoot ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Long Shoots ◽  
Short Shoots

Postflush observations on shoots of Betula papyrifera Marsh. indicated that long and short shoots differ in a range of morphological characteristics. Long shoots developed from distal axillary buds and short shoots developed from proximal axillary buds on the previous year's long shoots. Consequently, the potential of a bud to develop into a long shoot decreased basipetally. Potential long-shoot buds had higher bud-relative growth rates, stem-relative growth rates, leaf-relative growth rates, and stem dry weights during the course of postflush growth. Changes in leaf thickness, expressed in terms of specific leaf area and specific leaf weight, indicated that long shoots temporarily had thinner leaves than did short shoots a few weeks after flushing. Net assimilate requirements in long shoots for late leaf and internodal expansion may explain these observations. Nearing maturity, long-shoot early leaves became thicker, possibly owing to greater shoot vigour and (or) higher photosynthetic efficiency. Consequently, mature long-shoot early leaves possessed larger and thicker laminae, longer petioles, more side nerve pairs, and tended to grow more in length than width than short-shoot leaves on shoots of comparable age. Leaves of older short shoots, 2–10 years old, attained a greater size and had longer petioles than those of 1-year-old short shoots. Stem elongation and the development and expression of leaves in long shoots seemed to have a correlative influence on the overall vigour of long shoots.

The Pentoxylon plant

1985 ◽  
Vol 310 (1142) ◽  
pp. 77-108 ◽  
Keyword(s):  
Male Flower ◽  
Short Shoot ◽  
Female Cone ◽  
Leafy Shoots ◽  
Long Shoots ◽  
Short Shoots ◽  
Type 3 ◽  
Head Type

The various dispersed organs belonging to the Pentoxylon plant viz. Pentoxylon (stem), Nipaniophyllum (leaf), Sahnia (male flower) and Carnoconites (female cone) have been studied in detail. Apart from the long shoots (type 1 shoots), the plant bore three different kinds of short shoots: the thick woody short shoots, each with a broadly conical head (type 2 shoots); the slender parenchymatous short shoots (type 3 shoots); and the slightly thicker parenchymatous short shoot (type 4 shoot) terminating in a Sahnia flower. In addition to the well known Nipaniophyllum raoi leaves a second species, N. hobsonii sp. nov., is recognized. In Sahnia the sporangiophores were borne on a collar-like structure formed by the raised margin of the receptacle. The broadly conical head of the thick woody short shoot (type 2 shoot) might be the basis of the cone-bearing branchlets of Carnoconites fruits. The seeds of Carnoconites are spirally arranged rather than being in longitudinal rows as previously suggested. Pentoxylon was probably a shrubby plant which grew beside water. It sent up erect branched leafy shoots which after a few seasons of growth flopped onto the ground or on other stems, making a thicket. Although the stem, Pentoxylon , resembles Medullosa and Rhexoxylon anatomically, the reproductive parts of the plant, Sahnia and Carnoconites , are unlike those of any group of gymnosperms. The Pentoxylon plant is accordingly regarded as an extinct gymnosperm of unknown affinity. Nipanioxylon guptai has previously been regarded as related to Pentoxylon , but its holotype is believed to be a conifer and has nothing to do with the Pentoxylon plant.

Shoot-length frequencies in black birch (Betula lenta)

1991 ◽  
Vol 21 (10) ◽  
pp. 1475-1480 ◽  
Author(s):  
Brayton F. Wilson
Keyword(s):  
Main Axis ◽  
Shoot Length ◽  
Short Shoot ◽  
Lateral Shoot ◽  
Shoot Production ◽  
Shoot Number ◽  
Individual Branch ◽  
Axis Elongation ◽  
Long Shoots ◽  
Short Shoots

Lengths of all parent and current shoots were measured on three 8- to 10-year-old black birch (Betulalenta L.) trees with branches <8 years old. Older branches had more short shoots (<1 cm long) and shorter long shoots (>2 cm long) than younger branches. Parent long shoots produced three to nine basal short shoots. Observations on short-shoot production were consistent with the hypothesis that only buds with adequate nutrition formed long shoots. Three growth rules were developed for a model that simulated individual branch growth: (i) a regression predicting lateral shoot number from each parent shoot length; (ii) probabilities for the number of short shoots produced by a parent shoot based on the total number of current shoots produced per parent shoot; (iii) a regression predicting current shoot length from parent shoot length, current shoot position (longest to shortest), branch age, and main-axis elongation in the current and previous year. Simulations of 81 branches using these rules predicted shoot numbers and total shoot lengths close to those of the actual branches (R2 = 0.73–0.84).

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