Initiation and development of subterminal buds in Abiesbalsamea

1977 ◽  
Vol 7 (2) ◽  
pp. 258-262 ◽  
Author(s):  
G.R. Powell
Keyword(s):  
Balsam Fir ◽  
Bud Burst ◽  
Shoot Apices ◽  
Continuous Layer ◽  
Lateral Buds ◽  
Terminal Bud ◽  
Vegetative Bud ◽  
Different Origin ◽  
Needle Primordia

On mature, sapling, and seedling trees of balsam fir (Abiesbalsamea (L.) Mill.) cataphyll production on shoot apices began 3 to 4 weeks before vegetative bud burst. Subterminal bud primordia were initiated in the axils of two or three of the first-formed cataphylls at about the time of vegetative bud burst. A week later, prophylls were evident on the subterminal bud apices. Cataphylls were subsequently produced until mid-July. Most buds then initiated needle primordia and increased in size until late September. Some, on weaker shoots, failed to produce needles and remained latent. Throughout their development, the subterminal buds were never dissociated from the terminal bud and, together, the buds formed a terminal bud unit, ultimately encased in a continuous layer of resin. The subterminal buds produce the nodal branches which are distinctly more vigorous than internodal branches, which are produced in lateral buds which have a different origin.

Gibberellin A4/7 enhances seed-cone production in field-grown black spruce

1988 ◽  
Vol 18 (1) ◽  
pp. 139-142 ◽  
Author(s):  
Rong H. Ho
Keyword(s):  
Vitamin E ◽  
Black Spruce ◽  
Seed Orchard ◽  
Shoot Elongation ◽  
Bud Burst ◽  
Lateral Shoot ◽  
Cone Production ◽  
Seed Cone ◽  
Vegetative Bud ◽  
Needle Primordia

Black spruce (Piceamariana (Mill.) B.S.P.) grafts growing in a seed orchard were sprayed with gibberellin A4/7, and grafts and trees in families growing in arboreta were sprayed with gibberellin A4/7 and (or) vitamin E from vegetative bud burst to the end of shoot elongation. Gibberellin A4/7 was very effective in promoting seed cones and 400 mg/L appeared optimal. Vitamin E at 1000 mg/L was not effective. Vegetative bud burst occurred in mid-May and shoot elongation ended in late June. Needle primordia were visible on the apices of newly formed buds at the end of June. Reproductive buds had fewer bud scales than vegetative buds. It appeared that potential reproductive buds terminated their bud scale initiation earlier. Gibberellin A4/7 application to promote seed-cone production should be carried out before bud-type differentiation. This coincides with the end of lateral shoot elongation.

Shoot ontogeny in Arctostaphylos uva-ursi (bearberry): the annual cycle of apical activity

1984 ◽  
Vol 62 (9) ◽  
pp. 1925-1932 ◽  
Author(s):  
W. R. Remphrey ◽  
T. A. Steeves
Keyword(s):  
Leaf Primordia ◽  
Growth Strategy ◽  
Bud Burst ◽  
Foliage Leaf ◽  
Lateral Buds ◽  
Previous Season ◽  
Lateral Shoots ◽  
Terminal Buds ◽  
Floral Bracts ◽  
Vegetative Bud

Phenological investigation of shoot ontogeny in the prostrate shrub Arctostaphylos uva-ursi (L.) Spreng. (bearberry) at two sites in Saskatchewan, Canada, revealed that most growth occurred from May to July. Vegetative bud swell and leaf primordium initiation began around the 1st of May. Following bud burst in late May, elongation of most shoots continued for 3 to 5 weeks. Most bearberry shoots were not completely preformed; that is, several neoformed foliage leaves were initiated during current-year shoot extension in addition to the leaves that had been preformed during the previous season and had overwintered in the bud. In many shoots, a terminal inflorescence was initiated in the latter part of May of the year prior to anthesis. During conversion to the flowering state, the terminal apex initiated seven to nine floral bracts, each subtending a bud. In vegetative terminal shoots, bud-scale initiation also began in mid-May to late May and new terminal buds were first evident in early to mid-June. Following the initiation of bud scales and transitional leaves, the production of preformed foliage-leaf primordia continued until about August 1. Protruding lateral buds were evident histologically in the axils of preformed leaves during the initial stages of bud swell. On long, dominant shoots numerous neoformed leaves were initiated and shoot extension was often prolonged well into August. Second-flush terminal and lateral shoots, which resulted from the expansion of neoformed leaves and internodes, were also observed. The occurrence of neoformed growth in a large proportion of shoots suggests an exploitive, opportunistic growth strategy in this species.

Studies on the sultana vine. III. Pruning experiments with constant number of buds per vine, number and length of cane varied inversely

1955 ◽  
Vol 6 (6) ◽  
pp. 823 ◽  
Author(s):  
AJ Antcliff ◽  
WJ Webster ◽  
P May
Keyword(s):  
Apical Dominance ◽  
Variable Length ◽  
Bud Burst ◽  
Constant Number ◽  
Terminal Bud ◽  
Bud Position

Pruning experiments are described in which the number of buds per vine was kept constant, and the number and length of canes was varied inversely. The position of the pruning cut affected per cent. bud burst at only the two terminal bud positions, and did not affect per cent. fruitful shoots a t any bud position. For any length of cane likely to be used in practice, per cent. bud burst in the most fruitful region would not be affected. For a constant pruning level there were no significant differences in yield when length of cane was varied from 11 to 18 buds, but in years of high fruitfulness yield was significantly depressed when the canes were 25 buds long. Apical dominance could also be demonstrated on vines with canes of variable length, and it was shown that the inhibiting agent did not move transversely.

Promoting bud development in balsam fir Christmas trees with 6-benzylaminopurine

1984 ◽  
Vol 14 (3) ◽  
pp. 447-451 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Aqueous Solution ◽  
Shoot Elongation ◽  
Balsam Fir ◽  
Tween 20 ◽  
Carrier Solution ◽  
Mineral Deficiency ◽  
Bud Development ◽  
Time Of Application ◽  
Christmas Trees ◽  
Lateral Buds

The entire crown of variously fertilized, unsheared Abiesbalsamea (L.) Mill. trees was sprayed once or twice weekly for 2, 4, or 8 weeks with an aqueous solution of 0 or 600 mg 6-benzylaminopurine (BAP) L−1 containing 1.5% dimethyl sulfoxide, 13.5% methanol, and 0.1% Tween 20, starting at different times during the period of shoot elongation. In the year of application, BAP inhibited the elongation of the current-year shoot, increased the number of lateral buds formed on this shoot, and induced lammas growth. Both BAP and the carrier solution caused some phytotoxicity in current-year needles. Responses to BAP treatment varied markedly with genotype, whorl position, and time of application, and decreased with mineral deficiency, and decreasing BAP dosage. After overwintering, many of the BAP-induced lateral buds elongated, resulting in an increased number of shoots, hence in a denser crown.

Effects of stem injections of gibberellin A4/7 and paclobutrazol on sex expression and the within-crown distribution of seed and pollen cones in black spruce (Picea mariana)

1998 ◽  
Vol 28 (5) ◽  
pp. 641-651 ◽  
Author(s):  
Ronald F Smith
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Sex Expression ◽  
Bud Burst ◽  
Seed Orchards ◽  
Adjunct Treatment ◽  
Cone Production ◽  
Pollen Cone ◽  
Dose Dependent ◽  
Vegetative Bud

Two experiments in black spruce (Picea mariana (Mill.) BSP) seedling seed orchards were established to determine if a stem injection of paclobutrazol (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl) could be used as an adjunct treatment to increase the efficacy of stem injections of gibberellins A4 and A7 (GA4/7). Trees received a single injection of GA4/7 and (or) paclobutrazol shortly after vegetative bud burst. There was a dose-dependent but nonlinear increase in the production of cones of both sexes in response to stem injections of either GA4/7 or paclobutrazol. The optimum rate of GA4/7 for stimulating pollen-cone production was 3.3 mg, whereas the most seed cones were induced on trees receiving 11 mg. The sex ratio (number of seed cones/number of pollen cones) increased with the rate of GA4/7 applied. Injecting paclobutrazol also promoted cones of both sexes equally, resulting in sex ratios comparable with that of the control trees. Treatments did not affect the total numbers of buds (vegetative, latent, and cone) produced. Seed- and pollen-cone buds occurred in positions that would have otherwise developed vegetatively and become latent, respectively. The mechanisms whereby paclobutrazol could affect flowering in black spruce are discussed. The use of paclobutrazol as an adjunct to GA4/7 treatments in black spruce seedling seed orchards appears effective, practical, and safe.

Promotion of flowering in western hemlock by gibberellin A4/7 applied at different stages of bud and shoot development

1989 ◽  
Vol 19 (8) ◽  
pp. 1051-1058 ◽  
Author(s):  
John N. Owens ◽  
Anna M. Colangeli
Keyword(s):  
Effective Treatment ◽  
Shoot Elongation ◽  
Shoot Development ◽  
Western Hemlock ◽  
Bud Burst ◽  
Cone Production ◽  
Seed Cone ◽  
Pollen Cone ◽  
Vegetative Bud

Cone buds were induced on container-grown and field-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) clones during a 3-year period to study the effects of time and duration of gibberellin A4/7 treatment on cone induction, sexuality of cones, and to relate these results to bud and shoot development. The most effective treatment times preceded anatomical differentiation. The most abundant pollen cones and seed cones were produced when trees were sprayed with gibberellin A4/7 before vegetative bud burst and early shoot elongation. Two to three weekly gibberellin A4/7 applications starting at preswollen and swollen-bud stages were adequate for pollen-cone production. Pollen-cone production decreased when the applications were started at vegetative bud burst or during early shoot elongation. A minimum of three weekly applications were required for seed-cone production, and applications were equally effective when started at preswollen, swollen, and vegetative bud burst stages. Seed-cone production decreased when three weekly applications were started during early shoot elongation; however, this was overcome by increasing the number of applications.

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative processes in Douglas-fir. III. Effects on anatomy of shoot elongation and terminal bud development

1985 ◽  
Vol 15 (2) ◽  
pp. 354-364 ◽  
Author(s):  
J. N. Owens ◽  
J. E. Webber ◽  
S. D. Ross ◽  
R. P. Pharis
Keyword(s):  
Shoot Elongation ◽  
Douglas Fir ◽  
Apical Growth ◽  
Root Pruning ◽  
Bud Development ◽  
Leaf Initiation ◽  
Terminal Bud ◽  
Terminal Buds ◽  
Effective Cone ◽  
Vegetative Bud

The relative importance of cell division and cell elongation to shoot elongation and the anatomical changes in vegetative terminal apices were assessed for 9- and 10-year-old seedlings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in response to two effective cone-induction treatments, gibberellin A4/7 (GA4/7) and root-pruning (RP). Root-pruning was done in mid-April at the start of vegetative bud swelling and GA treatments were begun at vegetative bud flushing in mid-May and continued until early July. Shoot elongation before flushing resulted primarily from cell divisions and was not affected by the RP treatment. Shoot elongation after flushing resulted primarily from cell expansion which was reduced by RP treatments. Root-pruning significantly slowed mitotic activity, apical growth, and development of vegetative terminal buds from mid-June through mid-July. Apical growth then resumed during leaf initiation and the final number of leaf primordia initiated was not affected. This resulted in a delay of 2 to 4 weeks in the transition from bud-scale to leaf initiation. Retarded terminal vegetative apices anatomically resembled latent axillary apices but were never completely inhibited. GA + RP had the same effect as RP. GA4/7 alone had no effect on shoot or apical development. These results show that RP and GA + RP significantly retard shoot elongation and terminal bud development but still allow normal development of vegetative terminal buds. Retardation of bud development by a few weeks shifts the critical morphogenetic phase of transition from bud scale to leaf initiation to a later time when endogenous and environmental conditions may differ from the normal.

Missing growth rings at the trunk base in suppressed balsam fir saplings

2002 ◽  
Vol 32 (10) ◽  
pp. 1776-1783 ◽  
Author(s):  
Sylvain Parent ◽  
Hubert Morin ◽  
Christian Messier
Keyword(s):  
Radial Growth ◽  
Adventitious Roots ◽  
Abies Balsamea ◽  
Dry Mass ◽  
Balsam Fir ◽  
Leaf Biomass ◽  
Growth Rings ◽  
Terminal Bud ◽  
Below Ground ◽  
Age Estimates

Numerous researchers have suggested a causal relationship between low leaf biomass in suppressed trees and the lack of radial growth at the base of the trunk. The objective of this study was to verify this relationship with suppressed balsam fir (Abies balsamea (L.) Mill.) saplings found growing in an old-growth fir stand. A total of 29 saplings varying in height from 67 to 183 cm were uprooted. All saplings had adventitious roots. All terminal bud scars (TBS) found between the apex of the terminal leader and the trunk base (first adventitious root) as well as those found below ground were localized, and rings were counted between TBS along the aboveground trunk. Various morphological traits and the ratio of photosynthetic tissue dry mass (P, needles) to non-photosynthetic tissue dry mass (nP, aboveground stem) were used as an indicator of tree vigour. Between 3 and 33 rings counted along the aboveground trunk were missing at the trunk base. The number of missing rings at the base of the trunk was correlated with total height (r = 0.41), height growth (r = –0.51), radial growth (r = –0.44), the P/nP ratio (r = –0.73), and the proportion of live crown (r = –0.62). Moreover, from 2 to 35 additional rings, missing at the trunk base, were found in the belowground section of trunk and these missing rings were associated with the adventitious roots phenomenon. In conclusion, suppressed firs had missing rings at the base of the trunk. When all of the missing rings were added to the number of rings counted at the base of the trunk, age estimates provided a different temporal pattern of recruitment compared with that obtained by solely counting rings at the base of the trunk. Stem analysis on the entire trunk is the best aging method for suppressed balsam fir saplings.

Primary longitudinal resin canals in lodgepole pine occur in Fibonacci numbers

2004 ◽  
Vol 82 (10) ◽  
pp. 1539-1544 ◽  
Author(s):  
Arthur L Fredeen ◽  
Kevin T Hoekstra ◽  
Robert W Madill
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Fibonacci Numbers ◽  
Stem Diameter ◽  
Branch Order ◽  
Lateral Buds ◽  
Terminal Bud ◽  
Resin Canals

Primary (nontraumatic) longitudinal resin canals (RCs) in immature (expanding) and mature stems of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were found to occur in Fibonacci (F) numbers (specifically 5, 8, 13, and 21). The most commonly observed number of RCs in immature stem circumferences was 13 (53% of all immature stems surveyed), but 8, 21, and 5 were also observed in decreasing order of prevalence, respectively. In general, the greater the immature stem diameter, the higher the F number of the RCs. However, branch order appeared to have the greatest effect on the number of RCs. Specifically, the leader (1° axis) generally had 21 RCs in the terminal bud and 13 in the lateral buds. All other terminal axes (i.e., 2°, 3°, 4°) tended to 13, while associated lateral axes tended to 8. The same general relationships between number of RCs, stem diameter, and branch order were also observed for mature (woody) branchlets of lodgepole pine, for example, 13 RCs were also the most prevalent F number observed (i.e., in 48% of the observed branchlets). The phyllotactic chirality was also assessed for mature branch samples. A tree tends to retain a phyllotactic chirality (or handedness) as branch order increases, despite decreases in the number of RCs from 21 to 5 from low to high branch orders. The implication of these findings to helical phyllotactic development in conifers is discussed.Key words: Fibonacci numbers, resin canals, lodgepole pine, Pinus contorta var. latifolia, phyllotaxis.

scholarly journals 760 PB 184 INDOLE-3-ACETIC ACID REGULATES APICAL DOMINANCE BY CONTROLLING THE STATE OF WATER AND MEMBRANE LIPID COMPOSITION IN BUDS OF MALUS DOMESTICA BORKH

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 541h-542
Author(s):  
Shiow Y. Wang ◽  
Miklos Faust ◽  
Michael J. Line
Keyword(s):  
Acetic Acid ◽  
Lipid Composition ◽  
Apical Dominance ◽  
Membrane Lipid ◽  
Proton Density ◽  
Membrane Lipid Composition ◽  
Lateral Buds ◽  
Terminal Bud ◽  
Lateral Bud ◽  
Indole 3 Acetic Acid

The effect of Indole-3-acetic acid (IAA) on apical dominance in apple (Malus domestica Borkh.) buds was examined by studying changes In proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral bud paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed. Delaying this application weakens the effect of IAA. An increase in proton density in lateral buds was observable 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Decapitating the terminal bud induced an increase in membrane galacto- and phospholipids. and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also induced a decrease in the ratio of free sterols to phospholipids in lateral buds. Application of IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in the membrane lipid composition of lateral buds.

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