Enhancement of shoot elongation in Douglas-fir by gibberellin A4/7 and its relation to the hormonal promotion of flowering

1983 ◽  
Vol 13 (5) ◽  
pp. 986-994 ◽  
Author(s):  
Stephen D. Ross
Keyword(s):  
Stem Elongation ◽  
Maximum Growth ◽  
Shoot Elongation ◽  
Early Spring ◽  
Douglas Fir ◽  
Threshold Concentration ◽  
Physiological Age ◽  
Growth Enhancement ◽  
Bud Burst ◽  
Treatment Timing

The enhanced stem elongation that frequently accompanies the gibberellin A4/7 (GA4/7) promotion of flowering in Pinaceae species was investigated for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) vegetative propagules in relation to their physiological age, GA4/7 concentration, and treatment timing. Maximum growth enhancement, but marginal promotion of flowering (males and females), occurred when GA4/7 was applied in early spring before vegetative buds had begun to swell. In contrast, shoot elongation was only slightly enhanced when GA4/7 treatment was timed (vegetative bud burst ±4.5 weeks) to bracket the critical period for effecting differentiation of axillary primordia into cone buds. Also, the GA4/7 concentration optimal for flowering was supraoptimal for shoot elongation, and the growth response to GA4/7 decreased, whereas the flowering response increased, with increasing physiological age of the propagules (scions 4–45 years old). These findings are consistent with a hypothesis that exogenous GA4/7 is first utilized for vegetative growth processes, increased flowering occurring only after a threshold concentration is reached.

Effects of temperature during bud burst on pear thrips damage to sugar maple

1992 ◽  
Vol 22 (8) ◽  
pp. 1147-1150 ◽  
Author(s):  
T.E. Kolb ◽  
D.A.J. Teulon
Keyword(s):  
Sugar Maple ◽  
Stem Elongation ◽  
Dry Weight ◽  
Early Spring ◽  
Growth Time ◽  
Cool Temperature ◽  
Bud Burst ◽  
Warm Temperature ◽  
Reduced Height ◽  
Time Required

Sugar maple (Acersaccharum Marsh.) seedlings were exposed to either cool (11.9 °C) or warm (18.2 °C) temperatures in the presence or absence of adult pear thrips (Taeniothripsinconsequens Uzel) during bud burst and early spring growth. Time required for spring stem elongation was shorter at the warm temperature than at the cool temperature. Thrips feeding reduced height, leaf area, and seedling dry weight at both temperatures, and reductions were greater at the cool temperature than at the warm temperature. The results indicate that cool temperatures that slow bud burst promote pear thrips damage to sugar maple leaves.

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative process in Douglas-fir. II. Effects on shoot elongation and its relationship to flowering

1985 ◽  
Vol 15 (2) ◽  
pp. 348-353 ◽  
Author(s):  
J. E. Webber ◽  
S. D. Ross ◽  
R. P. Pharis ◽  
J. N. Owens
Keyword(s):  
Synergistic Effect ◽  
Vegetative Growth ◽  
Shoot Growth ◽  
Shoot Elongation ◽  
Douglas Fir ◽  
Threshold Concentration ◽  
Root Pruning ◽  
Flowering Response ◽  
Seed Cone ◽  
Female Flowering

Shoot elongation and female flowering response were assessed for gibberellin A4/7 (GA4/7) and root-pruning (RP) treatments in 9- and 10-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings of families with good- and poor-flowering histories. In families with a poor-flowering history, stem injections of GA4/7 significantly enhanced elongation of third-whorl terminal shoots but produced no flowering response. In families with a good-flowering history, GA4/7 treatment had no effect on shoot elongation but did result in a significant increase in seed-cone buds. In contrast, root-pruning significantly retarded shoot growth in families with both good- and poor-flowering histories and was also the single most effective treatment for enhancing flowering. Combined, GA4/7 plus RP had a synergistic effect on flowering and GA4/7 partially overcame the inhibition of shoot growth caused by RP alone. These results are consistent with a hypothesis that exogenous and endogenous gibberellins are used preferentially for vegetative growth processes, with increased flowering occurring only after a threshold concentration of effector gibberellins is reached.

Effect of heat and its timing within a polyhouse on flowering in potted Douglas-fir trees

1992 ◽  
Vol 22 (5) ◽  
pp. 736-739 ◽  
Author(s):  
Stephen D. Ross
Keyword(s):  
Heat Treatment ◽  
Low Temperatures ◽  
Shoot Elongation ◽  
Douglas Fir ◽  
Naphthaleneacetic Acid ◽  
Bud Burst ◽  
Rooted Cuttings ◽  
Ambient Temperatures ◽  
Temperature Regimen ◽  
Vegetative Bud

Female and male flowering in potted Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) rooted cuttings treated with gibberellin A4/7, with and without naphthaleneacetic acid, were inhibited by heat treatment in a closed polyhouse with a temperature regimen of 28:15 °C (day:night) relative to the flowering achieved in an open-sided polyhouse with near-ambient temperatures. The effect was greater for an early heat treatment (from vegetative bud burst to end of shoot elongation), which bracketed cone-bud differentiation, than for a following late heat treatment of similar duration. Effects of the early plus late heat treatments were additive. It was not the objective of this study to determine the optimal temperature regimen for flowering. However, other than possibly in locations where low temperatures prevail during cone-bud differentiation in spring, heat treatment within a polyhouse appears to be neither a necessary nor desirable adjunct to gibberellin A4/7 for promotion of flowering in potted Douglas-fir.

Phenology ofChrysothamnus viscidiflorussubspeciesviscidiflorus(Hook.) Nutt.

Weed Science ◽  
1974 ◽  
Vol 22 (5) ◽  
pp. 469-475 ◽  
Author(s):  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
Soil Moisture ◽  
Growth Pattern ◽  
Stem Elongation ◽  
Growth Period ◽  
Early Spring ◽  
Growth Patterns ◽  
Late Spring ◽  
Bud Burst ◽  
Accelerated Growth ◽  
Vegetative Bud

The configuration of the growth pattern forChrysothamnus viscidiflorus(Hook.) Nutt. was determined from vegetative bud burst to flowering. Important portions of the pattern are: restrictive growth during early spring, accelerated growth in late spring when the optimum susceptibility to herbicides occurs, and a leveling off of growth before flowering. Seedlings and young plants have a more rapid and greater annual stem elongation than mature or senescent plants. Elongation during the accelerated growth period can be predicted from early spring growth with moderate precision when soil moisture and temperatures are not limiting. Populations growing on sites of higher or lower elevations or of pronounced aspect will have growth patterns moderately varying from the modal populations. The greatest factor influencing the growth pattern on years with adequate soil moisture was competition from other species and the combination of competition and age of the rabbitbrush plants.

Growth and Branching Responses of Portulaca grandiflora to Foliar Applications of Chemical Growth Regulators

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 447c-447
Author(s):  
T.J. Banko ◽  
M.A. Stefani
Keyword(s):  
Growth Regulators ◽  
Growth Habit ◽  
Stem Elongation ◽  
Block Design ◽  
Shoot Elongation ◽  
Main Shoot ◽  
Randomized Complete Block Design ◽  
Portulaca Grandiflora ◽  
Prostrate Growth ◽  
Secondary Shoot

During container production of portulaca, growth of long, prostrate, sparsely branched stems makes handling of plants difficult, and reduces their commercial appeal. Growers prefer to minimize shoot elongation while increasing branching to provide a full, compact plant. The objectives of this study were to evaluate growth regulators for promotion of branching and inhibition of stem elongation. Container-grown plants ≈21 cm in diameter were treated with sprays of ProShear (benzylaminopurine) at 62.4, 125, and 250 ppm; Promalin (benzyaminopurine + gibberellins 4+7) at 125, 250, and 500 ppm; Atrimmec (dikegulac) at 250, 500, and 750 ppm; and Florel (ethephon) at 250, 500, and 750 ppm. These treatments were compared with untreated controls in a randomized complete-block design. Main shoot lengths were measured at 16, 31, and 51 days after treatment (DAT). Numbers of new shoot breaks were counted 16 DAT. The growth habit, that is, tendency to grow upright or prostrate, was also evaluated 16 DAT. The most-effective material for retarding primary shoot elongation and for stimulating secondary shoot development was ProShear. At 16 DAT, 250 ppm ProShear reduced shoot elongation by 25% compared to control plants. This treatment also increased the number of secondary shoot breaks by 143%. Promalin increased the number of new shoot breaks, but it also increased the lengths of all shoots. High rates of Florel and Promalin caused shoots to grow predominantly upright rather then prostrate. ProShear, however, caused more prostrate growth as rate increased.

Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Stem Elongation ◽  
Tree Height ◽  
Shoot Elongation ◽  
Main Stem ◽  
Tree Age ◽  
Precommercial Thinning ◽  
Two Factors ◽  
Artificial Inoculations

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

EARLYWOOD VESSELS IN RING-POROUS TREES BECOME FUNCTIONAL FOR WATER TRANSPORT AFTER BUD BURST AND BEFORE THE MATURATION OF THE CURRENT-YEAR LEAVES

IAWA Journal ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 315-331 ◽  
Author(s):  
Peter Kitin ◽  
Ryo Funada
Keyword(s):  
Water Transport ◽  
Time Course ◽  
Growing Season ◽  
Early Spring ◽  
Vessel Element ◽  
Full Time ◽  
Bud Burst ◽  
Long Time ◽  
Wall Perforation ◽  
Earlywood Vessels

This paper reviews the development of xylem vessels in ring-porous dicots and the corresponding leaf phenology. Also included are our original observations on the time-course of vessel element growth, secondary wall deposition, and end wall perforation in the deciduous hardwood Kalopanax septemlobus. Different patterns of xylem growth and phenology serve different strategies of the species for adaptation to seasonal climates. Trees with ring-porous xylem form wide earlywood vessels (EWV) in spring and narrow latewood vessels in summer. The wide EWV become embolized or blocked with tyloses by the end of the growing season while the narrow vessels may remain functional for many years. The co-occurrence of wide and narrow vessels provides both efficiency and safety of the water transport as well as a potentially longer growing season. It has for a long time been assumed that EWV in ring-porous hardwoods are formed in early spring before bud burst in order to supply sap to growing leaves and shoots.However, the full time-course of development of EWV elements from initiation of growth until maturation for water transport has not been adequately studied until recently. Our observations clarify a crucial relationship between leaf maturation and the maturation of earlywood vessels for sap transport. Accumulated new evidence shows that EWV in branches and upper stem parts develop earlier than EWV lower in the stem. The first EWV elements are fully expanded with differentiated secondary walls by the time of bud burst. In lower stem parts, perforations in vessel end walls are formed after bud burst and before the new leaves have achieved full size. Therefore, the current-year EWV network becomes functional for water transport only by the time when the first new leaves are mature.

Phenology of Bud Burst in Douglas-Fir Related to Provenance, Photoperiod, Chilling, and Flushing Temperature

1975 ◽  
Vol 136 (3) ◽  
pp. 290-298 ◽  
Author(s):  
Robert K. Campbell ◽  
Albert I. Sugano
Keyword(s):  
Douglas Fir ◽  
Bud Burst

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative processes in Douglas-fir. IV. Effects on lateral bud development

1986 ◽  
Vol 16 (2) ◽  
pp. 211-221 ◽  
Author(s):  
J. N. Owens ◽  
J. E. Webber ◽  
S. D. Ross ◽  
R. P. Pharis
Keyword(s):  
Normal Development ◽  
Shoot Elongation ◽  
Douglas Fir ◽  
Root Pruning ◽  
Lateral Shoot ◽  
Bud Development ◽  
Lateral Bud ◽  
Mitotic Frequency ◽  
Bud Initiation ◽  
Vegetative Bud

The anatomy, mitotic frequency, size, and total insoluble carbohydrate histochemistry was studied in axillary apices from 9- and 10-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees after cone induction treatments of root-pruning and (or) stem injections of a gibberellin A4 and A7 (GA4/7) mixture. Axillary buds were initiated at the time of root-pruning, but root-pruning treatment had no effect on axillary bud initiation. Axillary apices from control and gibberellin-treated trees were similar and followed the normal sequence of bud-scale initiation, differentiation, and leaf initiation (described previously) and no cone buds differentiated. Early development of axillary apices from root-pruned and root-pruned, gibberellin-treated trees was normal, but development became retarded near the time of vegetative bud flush. Retarded apices were small with low mitotic frequency and developed many features characteristics of latent apices. Retardation of axillary apices continued until mid-July when normal development resumed and apices differentiated into reproductive buds or vegetative buds, or became latent. The trees in which the greatest retardation of apical development occurred during lateral shoot elongation produced the most cone buds. These results are discussed in relation to hypotheses proposed to explain how cultural and gibberellin treatments affect cone induction in the Pinaceae.

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.

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