Girdling: its effect on carbohydrate status and on reproductive bud and cone development of Douglas fir

1971 ◽  
Vol 49 (3) ◽  
pp. 453-466 ◽  
Author(s):  
L. F. Ebell
Keyword(s):  
Shoot Elongation ◽  
Douglas Fir ◽  
Bud Break ◽  
Variable Response ◽  
Bud Development ◽  
Cone Production ◽  
Carbohydrate Concentration ◽  
Cone Development ◽  
Food Reserves ◽  
Vegetative Bud

Partial girdles were applied in August, 1957, to one stem of two double-stemmed, 20-year-old Douglas fir (Pseudotsuga menziesii (Mirb.) Franco). The second stem served as control. A third double-stemmed tree was treated in May, 1958. Cone production responses were obtained on all three girdled stems, averaging 7.4 times that of control stems in 1959, and 1.6 and 2.3 times that of control stems in 1961 and 1962. Cone production responses to treatment, and cone crop variation over several years were correlated with reduced bud failure during the period of new shoot elongation. Total number of buds per shoot was initially similar for paired stems. These relationships indicated a predetermined potential for annual cone production, and that cone crop periodicity is determined by later conditions favorable or unfavorable to continued early bud development. Treatment increased both sugars and starch in shoots sampled 40 days after August girdling, but only starch remained elevated the next spring and throughout the decisive May–June period of reproductive bud development. Other factors indicated food reserves to be related only weakly to reproductive bud survival. Cone production reduced carbohydrate concentration in shoots of all ages, growth and number of new shoots, and number of developed buds per shoot. These factors explain the absence of consecutive cone crops in Douglas fir, and suggest that cone inducing treatments should not be applied in good flowering years. Cone production responses on single-stemmed trees girdled at weekly intervals showed an optimum timing coincident with the onset of flowering, a more variable response up to the time of vegetative bud break, then an adverse effect on cone production when girdled later than 1 week after vegetative bud break.

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.

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.

Timing of gibberellin A4/7 application for cone production in potted black spruce grafts

1991 ◽  
Vol 21 (7) ◽  
pp. 1137-1140 ◽  
Author(s):  
Rong H. Ho
Keyword(s):  
Black Spruce ◽  
Foliar Spray ◽  
Shoot Elongation ◽  
Bud Break ◽  
Bud Burst ◽  
Lateral Shoot ◽  
Cone Production ◽  
Best Response ◽  
Seed Cone ◽  
Vegetative Bud

Potted 5-year-old grafts of black spruce (Piceamariana (Mill.) B.S.P.) growing in either a heated greenhouse or an outdoor holding area were sprayed weekly at 200 mg•L−1 gibberellin A4/7 for various durations and timings. The application began 1 to 6 weeks after vegetative bud break and continued until the end of lateral shoot elongation. Sprayings ended at the same time for all treatments, about 1 week before leaf primordial differentiation on the shoot apices. The best response in seed-cone production occurred when application began 2 weeks after bud break (midstage of rapid shoot elongation) and continued for 5 weeks; treatments were also effective when applications began 3 weeks after bud break or earlier and continued for 4 to 6 weeks. Treatments initiated later (4 to 6 weeks after bud break) were not effective. Grafts kept outdoors produced more seed cones than those kept indoors. The effects on cone production of gibberellin A4/7 application at four different concentrations were compared by spraying for 6 weeks, beginning 1 week after vegetative bud burst. Gibberellin A4/7 at 200 mg•L−1 was the lowest foliar spray concentration found to be effective in promoting seed-cone production.

Cone-Induction Response of Douglas Fir to Form of Nitrogen Fertilizer and Time of Treatment

1972 ◽  
Vol 2 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Lorne F. Ebell
Keyword(s):  
Nitrate Nitrogen ◽  
Shoot Elongation ◽  
Ammonium Nitrogen ◽  
Douglas Fir ◽  
Bud Break ◽  
Growth Responses ◽  
Specific Chemical ◽  
Cone Production ◽  
Nitrate Treatment ◽  
Old Trees

Cone production increases of 2.5, 5.0 and 1.5 times that of control were obtained the year following treatment with 400 lb nitrate nitrogen per acre (1 lb/acre = 1.12 kg/ha), applied 6 weeks before vegetative bud break, at the start of bud break, and 10 days after the midpoint of the bud break period, respectively, on 20-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco.). Cone counts of 15, 26, 72, 142 and 155 were obtained from 0, 200, 400, 800 and 1600 lb nitrate nitrogen per acre, applied to 13-year-old trees during early bud break. Ammonium nitrogen, applied at the same rates and times, was ineffective for stimulation of cone production on either age of tree. There were no differences in rate of accumulation of total nitrogen in buds and foliage, shoot-growth responses, or total number of buds per shoot due to form of nitrogen. Nitrate treatment enhanced cone production through a reduction in bud failure during the shoot elongation period. These results suggest responses are not primarily due to improved mineral nutrition, but to a specific chemical stimulation from critically timed changes in type of nitrogen metabolism. Possible influences of temperature and rainfall on natural cone crop periodicity and on proper timing of nitrate treatment are discussed.

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.

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.

Bud development in mountain hemlock (Tsuga mertensiana). II. Cone-bud differentiation and predormancy development

1984 ◽  
Vol 62 (3) ◽  
pp. 484-494 ◽  
Author(s):  
John N. Owens
Keyword(s):  
Shoot Elongation ◽  
Bud Development ◽  
Seed Cone ◽  
Cone Apex ◽  
Tsuga Mertensiana ◽  
Lateral Branches ◽  
Mother Cells ◽  
Pollen Cone ◽  
Bud Initiation ◽  
Vegetative Bud

Seed cones of Tsuga mertensiana (Bong) Carr. occur terminally on distal lateral branches and form from the differentiation of a terminal, previously vegetative apex, into a seed-cone apex. Pollen cones commonly occur on lateral branches and form from the differentiation of an undetermined axillary apex about 6 weeks after axillary bud initiation. Pollen cones also occasionally occur terminally. All cone buds began differentiation in late July after bud-scale initiation was complete and at about the end of lateral shoot elongation. Seed-cone buds initiated bracts and ovuliferous scales, but not ovules, before they became dormant at the end of October. Pollen-cone buds initiated all microsporophylls by early September. Microsporangia containing microspore mother cells differentiated before pollen-cone buds became dormant in mid-October. The time of cone-bud differentiation is related to vegetative bud and shoot development. The time and method of cone-bud differentiation is discussed in relation to T. heterophylla and other conifers having similar bud development.

scholarly journals Natural and Artificial Chilling of Southern Highbush Blueberry

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 825B-825
Author(s):  
Donna A. Marshall* ◽  
Stephen J. Stringer ◽  
James M. Spiers
Keyword(s):  
Bud Break ◽  
Delivery Method ◽  
Flower Bud ◽  
Bud Development ◽  
Chilling Requirements ◽  
Highbush Blueberries ◽  
Southern Highbush ◽  
Chilling Hours ◽  
Floral Bud ◽  
Vegetative Bud

A study was initiated in November, 2002 to determine the effects of exposing two Southern Highbush blueberries (Vaccinium corybosum L) to artificial chilling hours on initiation of bud break and advancement of floral and vegetative bud maturity. Plants of `Jubilee' and `Misty' were divided into 2 groups in which one was left outdoors, allowing chilling to occur and accumulate naturally, while the other group was placed in a growth chamber set at a constant artificial temperature of 4 °C. Five plants of each cultivar were then placed into a heated greenhouse after 0, 200, 400, 600, or 800 hours of chilling (total hours of exposure to <5 °C) had accumulated for forcing of flower bud development. The progression of floral bud development of the terminal three buds on five tagged stems was observed at 7-10 day intervals for 30 days. At the end of the forcing period observations were also made on total percent vegetative and floral bud break. Prior to accumulating sufficient chilling requirements, chilling delivery method did not appear to influence the rate of floral bud development since none advanced past stage 3 regardless of chilling regime used. However after chilling requirements were met, flower buds of plants that were allowed to chill naturally developed more quickly than did those chilled by artificial means.

Cone-Production and Stem-Growth Response of Douglas Fir to Rate and Frequency of Nitrogen Fertilization

1972 ◽  
Vol 2 (3) ◽  
pp. 327-338 ◽  
Author(s):  
Lorne F. Ebell
Keyword(s):  
Douglas Fir ◽  
Stem Volume ◽  
Wood Production ◽  
Foliar Nitrogen ◽  
Cone Production ◽  
Nitrogen Levels ◽  
Duration Of Effect ◽  
Dry Conditions ◽  
Vegetative Bud

Twenty-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco.) were treated in May with 0, 50, 100, 200,400, 800 and 1600 lb nitrogen per acre (1 lb/acre = 1.12 kg/ha) as ammonium nitrate. In 5 subsequent years, cone production with annual and biennial retreatment at one rate was compared with no retreatment. Heavy rainfall after the initial fertilization appeared responsible for small, similar cone-production responses the next year from the 100–1600 lb rates. Retreatment at 400 lb increased cone production of the third year but overfertilization occurred in combination with the higher initial rates. Initial overfertilization or annual refertilization reduced long-term responses. Responses were greatest when dry conditions followed treatment. It was concluded that 400 lb nitrate nitrogen per acre at the start of vegetative bud break, applied biennially to alternate halves of an area, would provide optimum long-term cone production.Stem growth benefited from increasing foliar nitrogen levels up to about 2%, obtained with 200–400 lb nitrogen per acre, and was adversely affected by foliar nitrogen above 3%. Response to fertilization consisted of: (1) direct effects of improved nitrogen status lasting about 2 years, (2) accumulative increases in leaf area favoring shoot and stem responses up to the 4th or 5th year, and (3) continued stem-area increases due to growth over the greater circumference resulting from factors 1 and 2. Over the full duration of effect in young stands, the optimum economic treatment for increased wood production may correspond closely to the 400 lb nitrogen per acre which provided near-optimum physiological responses. The 200 and 400 lb rates increased 5-year stem-volume increment by 62 and 90%.

Reproductive growth and development in seven provenances of lodgepole pine

1988 ◽  
Vol 18 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Conor O'Reilly ◽  
John N. Owens
Keyword(s):  
Growth And Development ◽  
Reproductive Growth ◽  
Bud Development ◽  
Cone Production ◽  
Growth Increments ◽  
Seed Cone ◽  
Cone Development ◽  
Pollen Release ◽  
The Times ◽  
Pollen Cone

Reproductive growth and development were studied in 1983 in seven provenances of Pinuscontorta Dougl. ssp. latifolia Engelm. growing in a provenance trial near Prince George, B.C. Stages of pollen release and seed-cone receptivity were scored by indices of cone development. Pollen- and seed-cone numbers were estimated and the distribution of seed cones within the upper crown and on annual growth increments of fourth-whorl branches was assessed. Pollen-and seed-cone bud development was followed in sectioned long-shoot buds taken at 2- to 3-week intervals. The times of maximum seed-cone receptivity and pollen release differed slightly among provenances, indicating that there was a high chance of cross-pollination. Differences among provenances in pollen-cone numbers were large, but smaller differences in seed-cone numbers were noted. No mature pollen cones or developing pollen-cone buds were found in the Yukon provenance. Seed-cone production varied with whorl position and was influenced by polycyclic long-shoot development. Potential pollen-cone buds were initiated from May until late June. Pollen cones first differentiated in early to mid July in all provenances. Potential seed-cone apices were noted from mid-June to late July and differentiation occurred in mid-July to early August, depending on provenance. Seed-cone bud development began first in the northern provenances.

Sign in / Sign up

Export Citation Format

Share Document