Stimulation of flowering by grafted black spruce and white spruce: a comparative study of the effects of gibberellin A4/7, cultural treatments, and environment

1991 ◽  
Vol 21 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Michael S. Greenwood ◽  
Gregory W. Adams ◽  
Michele Gillespie
Keyword(s):  
Black Spruce ◽  
White Spruce ◽  
Shoot Elongation ◽  
Height Growth ◽  
Root Pruning ◽  
Female Cone ◽  
Growth Cycles ◽  
Female Flowering ◽  
Chilling Treatment ◽  
Stimulation Of

Flower stimulation treatments, including gibberellin A4/7 (GA4/7) application, root-pruning, and greenhouse environment during the latter part of shoot elongation, were applied to grafted, clonal black spruce (Piceamariana (Mill.) B.S.P.) and white spruce (Piceaglauca (Moench) Voss) of roughly the same size and age. In addition, the size of pot-grown ramets of both species was increased by inducing additional growth cycles by several applications of a chilling treatment followed by an 18-h photoperiod in a heated greenhouse. This treatment doubled the height growth of both species over a 2-year period, and female cone bud production was promoted by GA4/7. GA4/7 also promoted female flowering on field-grown material, but root-pruning had little effect; black spruce was more responsive to GA4/7 (10× increase) than white spruce (3× increase). Male flowering in black spruce was consistently, and sometimes significantly, inhibited by GA4/7, but was promoted in white spruce. In the latter case the response was not statistically significant. In contrast, male flowering was increased in potted trees of both species by allowing shoots to elongate 50–75% outdoors, after which the trees were moved into a greenhouse.

Promotion of flowering in potted white spruce grafts by root pruning: its relationship to drought and shoot elongation

1991 ◽  
Vol 21 (5) ◽  
pp. 680-685 ◽  
Author(s):  
Stephen D. Ross
Keyword(s):  
Early Stage ◽  
White Spruce ◽  
Shoot Elongation ◽  
Threshold Level ◽  
Response To Treatment ◽  
Root Pruning ◽  
Flowering Response ◽  
Stress Effects ◽  
Female Flowering ◽  
Vegetative Bud

Flowering and shoot-elongation responses by potted white spruce (Piceaglauca (Moench) Voss) grafts to root pruning (RP) and drought, and to RP applied at different stages of root and shoot development, were investigated in separate experiments. Results suggest that RP does not simulate drought. Differences in midday needle water potentials between RP and non RP grafts were relatively small (0.1–0.2 MPa) and short lived following treatment. Furthermore, whereas RP only affected (promoted) female flowering, drought only affected (inhibited) male flowering. Shoot elongation was less inhibited by RP at initiation of new root growth in spring, compared with RP at the late vegetative bud swell stage and at the early stage of rapid shoot elongation, when root activity is naturally declining. However, the flowering response was independent of time of RP. The early RP treatment enhanced shoot elongation in some clones and inhibited it in others, and the effect was not related to the clone's flowering response to treatment. These results are discussed in relation to the hypothesis that in small, potted trees, at least, actively growing roots are an important source of certain gibberellins that are essential for both shoot elongation and cone-bud differentiation. Accordingly, RP may inhibit or enhance shoot elongation, depending on whether the supply of gibberellins from roots newly regenerated following RP exceeds that from existing roots removed in treatment. Flowering occurs when the supply of gibberellins exceeds some threshold level either because of reduced vegetative demand (due to water-stress effects) or increased synthesis by roots.

Black and White Spruce Plantings in Minnesota: Container vs Bareroot Stock and Fall vs Spring Planting

1983 ◽  
Vol 59 (4) ◽  
pp. 189-191 ◽  
Author(s):  
A. A. Alm
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Black Spruce ◽  
White Spruce ◽  
Height Growth ◽  
Artificial Regeneration ◽  
Black And White ◽  
Four Seasons ◽  
Spring Planting ◽  
Better Than

Black spruce (Picea mariana (Mill.) B.S.P.) and white spruce (Picea glauca (Moench) Voss) styrob-lock and paperpot and 3-0 and 2-2 seedlings were planted spring and fall. After four seasons of growth the container seedlings had survival and height growth as good or better than the nursery seedlings. There were no differences in performance between the two container systems. The 2-2 stock generally had better survival than the 3-0 stock. Survival of fall-planted stock was equal to or better than that of the spring-planted stock. Key words: white spruce, black spruce, styroplugs, paper pots, seedlings, transplants, artificial regeneration, fall vs spring planting

Promotion of flowering in young Larixlaricina grafts by gibberellin A4/7 and root pruning

1990 ◽  
Vol 20 (9) ◽  
pp. 1448-1452 ◽  
Author(s):  
Throstur Eysteinsson ◽  
Michael S. Greenwood
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Shoot Elongation ◽  
Root Pruning ◽  
Mature Trees ◽  
Foliar Sprays ◽  
Female Flowering

Flowering was promoted on potted, indoor, and field-grown 3-year-old juvenile and mature Larixlaricina (Du Roi) K. Koch grafts by foliar sprays of the plant-growth regulator gibberellin A4/7 and root pruning. Biweekly gibberellin A4/7 applications of three different durations, commencing at the start of long-shoot elongation, yielded similar increases in female flowering in the greenhouse; this effect was synergistically enhanced by root pruning. Male flowering was promoted by gibberellin A4/7 + root pruning in mature but not juvenile grafts. In the field, female flowering was also promoted by the gibberellin A4/7 treatment commencing at the start of shoot extension, but gibberellin A4/7 applications starting later were not effective. Grafted scions from mature trees responded significantly better to gibberellin A4/7 + root pruning than did seedling scions.

Floral response of Piceaglauca to gibberellin A4/7, napthaleneacetic acid, root-pruning, and biennial treatment

1985 ◽  
Vol 15 (4) ◽  
pp. 743-746 ◽  
Author(s):  
Robert D. Marquard ◽  
James W. Hanover
Keyword(s):  
Water Potential ◽  
Shoot Growth ◽  
White Spruce ◽  
Root Pruning ◽  
Female Cone ◽  
Cone Production ◽  
Napthaleneacetic Acid ◽  
Terminal Shoot ◽  
And Control ◽  
Male Strobili

The floral response of 6-year-old seedling white spruce (Piceaglauca (Moench) Voss.) was evaluated after treatment in 1981 with the gibberellin mixture of A4 and A7 (GA4/7), napthaleneacetic acid (NAA), and root-pruning. To evaluate the effectiveness of biennial treatment, trees treated in 1981 were again treated in 1983 and compared with a second group of trees treated only in 1983. Trees treated in 1981 with 500 mg•L−1 GA4/7 plus 25 mg•L−1 NAA and root-pruning averaged 42 female strobili per tree and control trees remained vegetative. Root-pruning significantly reduced terminal shoot growth and shoot water potential. No male strobili were produced on study trees. Trees treated in 1981 and again in 1983 were as productive (based on female counts) as trees treated only in 1983. Two treatments in 1983 significantly enhanced female strobilus production over the control: (i) 500 mg•L−1 GA4/7 alone and (ii) 250 mg•L−1 GA4/7 plus root-pruning. These treatments averaged 150 and 192 female strobili per tree, respectively; control trees averaged 30. Biennial treatment with GA4/7 and root-pruning can effectively continue to increase female cone production of white spruce.

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 applied growth regulators and cultural treatments on flowering and shoot growth of Pinustabulaeformis

1990 ◽  
Vol 20 (6) ◽  
pp. 679-685 ◽  
Author(s):  
Chuxing Sheng ◽  
Shasheng Wang
Keyword(s):  
Shoot Growth ◽  
Root Pruning ◽  
Naphthaleneacetic Acid ◽  
Vegetative Shoot ◽  
Female Cone ◽  
Male Cone ◽  
Female Flowering ◽  
Positive Effect ◽  
Stem Girdling ◽  
Hormonal Treatments

Fourteen treatments expected to promote and regulate flowering were administered to 7-year-old seedlings of Chinese pine (Pinustabulaeformis Carr.), and three were administered to 11-year-old grafted propagules. The cultural treatments, including root pruning, stem girdling, polyethylene mulching, and injection of gibberellin A3 (GA3) significantly increased male cone bud production of the young seedlings. For female flowering, however, only GA4 injection, alone and in combination with root pruning, had a statistically significant positive effect. N6-benzyladenine (BA) injection significantly decreased both male and female cone-bud production. There was no synergistic effect between the cultural and the hormonal treatments on flowering of the seedlings. Treatments with naphthaleneacetic acid dramatically enhanced male cone bud production of the grafted propagules, but did so at the expense of female cone bud production. The hormonal treatments (GA3, GA4, and BA injection) all promoted vegetative shoot growth of the treated seedlings. The cultural treatments generally inhibited shoot length growth and had no significant effect on diameter growth.

Morphological Effects of Root Pruning and Wrenching White Spruce Transplants

1988 ◽  
Vol 5 (4) ◽  
pp. 245-247
Author(s):  
Lisa J. Buse ◽  
Robert J. Day
Keyword(s):  
Growing Season ◽  
White Spruce ◽  
Shoot Elongation ◽  
Diameter Growth ◽  
Root Pruning ◽  
Fibrous Root ◽  
Root Collar Diameter ◽  
Collar Diameter ◽  
Root Collar

Abstract The principal objective of this research was to evaluate the effect of root pruning followed by wrenching on the morphological quality of 2 + 2 white spruce transplant stock during the final year on the nursery. In 1984, white spruce transplants were root pruned: (1) before shoot elongation; (2) during elongation; and (3) after elongation, followed by root wrenching at 28-day intervals until September (4, 3, and 2 times, respectively). In 1985, similar stock was root pruned before shoot elongation and (1) root wrenched at 21-day intervals (4 times), and (2) root wrenched periodically (twice). In both years, height and root collar diameter growth were monitored throughout the season. In the fall, morphological quality was assessed and bud samples were collected to determine the effects of root conditioning on primordia development. Root conditioning modified the morphology of stock in both years by reducing height and root collar diameter and inducing the development of a compact fibrous root system. Early season root pruning followed by wrenching at regular intervals throughout the growing season had the most effect on shoot and root morphology. Differences in results between years were attributed to environment. North. J. Appl. For. 5:245-247, December 1988.

Nutrient supply and belowground interaction alter responses to CO2 elevation in black spruce and white spruce

2020 ◽  
Vol 472 ◽  
pp. 118271 ◽  
Author(s):  
Qing-Lai Dang ◽  
Jacob Marfo ◽  
Fengguo Du ◽  
Md. Shah Newaz
Keyword(s):  
Black Spruce ◽  
White Spruce ◽  
Nutrient Supply ◽  
Co2 Elevation
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