Effect of nursery culture on morphological development of western hemlock seedlings during field establishment. I. Flushing, shoot elongation, and bud development

1994 ◽  
Vol 24 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Conor O'Reilly ◽  
J.N. Owens ◽  
J.T. Arnott ◽  
B.G. Dunsworth
Keyword(s):  
Cold Storage ◽  
Growing Season ◽  
Shoot Elongation ◽  
Moisture Stress ◽  
Western Hemlock ◽  
Morphological Development ◽  
Cavity Size ◽  
Bud Development ◽  
Nursery Culture ◽  
Dormancy Induction

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings grown in two different container cavity sizes that received four different dormancy induction treatments, short (SD) or long days (LD), in combination with moisture stress (D) or no moisture stress (W), in the greenhouse, and lifted and placed in cold storage (November, January, or March) were planted on two adjacent coastal reforestation sites on Vancouver Island, British Columbia, and monitored for phenological responses during the first growing season. The SD seedlings flushed sooner and began bud development later than the LD seedlings, although the effect on flushing was small for those lifted in March. Moisture stress and SD together in the greenhouse reduced shoot elongation rates but had little impact on field bud development. Cold storage of seedlings lifted in November and January delayed flushing, reduced shoot elongation rates, and advanced bud development compared with the March-lifted stock. The influence of cavity size was generally small on most variables measured. Shoot elongation was slightly faster on the southeast site than on the northwest site, whereas bud development was more rapid on the northwest site. The effect of site on date of flushing varied with nursery treatment.

Effect of nursery culture on morphological development of western hemlock seedlings during field establishment. II. Survival, shoot length components, and needle length

1994 ◽  
Vol 24 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Conor O'Reilly ◽  
J.N. Owens ◽  
J.T. Arnott ◽  
B.G. Dunsworth
Keyword(s):  
Shoot Growth ◽  
Unit Length ◽  
Moisture Stress ◽  
Western Hemlock ◽  
Morphological Development ◽  
Needle Length ◽  
Nursery Culture ◽  
Reverse Pattern ◽  
Dormancy Induction ◽  
Short Days

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings grown in two different container cavities that received four different dormancy induction treatments, short (SD) or long days (LD) in combination with moisture stress (D) or no stress (W) in the greenhouse, and lifted and placed in cold storage (November, January, or March), were planted on two adjacent coastal reforestation sites in British Columbia and monitored for survival and morphological development. Survival was greatest in seedlings grown in the larger cavities in the greenhouse, in seedlings lifted in March, and in seedlings not treated to moisture stress. Seedling shoots had more stem units on the southeast than the northwest site, but the amount varied with nursery treatment. Seedlings from the LD treatments produced more stem units during free growth and lammas growth than those from the SD treatment. Nevertheless, most shoot growth was predetermined in the buds during nursery culture, accounting for a minimum of 67% of the final number of stem units. Stem unit length (SUL) was longer in seedlings on the southeast site than on the northwest site for those treated to LD in the nursery. Seedlings treated to short days showed the reverse pattern (SDW) to this, or were unaffected by site (SDD). Shoots and needles were shortest for seedlings from the SDD treatment and for those lifted in November. Shoot growth was greatest for seedlings lifted in March and for those treated with LD, mainly owing to their longer SUL. Lammas growth was most frequent in seedlings from the smaller cavities, and in those from the November and March lifts.

Bud development in western hemlock. I. Annual growth cycle of vegetative buds

1973 ◽  
Vol 51 (11) ◽  
pp. 2223-2231 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Mitotic Activity ◽  
Shoot Elongation ◽  
Growth Cycle ◽  
Leaf Primordia ◽  
Annual Growth ◽  
Western Hemlock ◽  
Bud Burst ◽  
Bud Development ◽  
Vegetative Buds ◽  
Number Of Leaves

Vegetative apices of mature Tsnga heterophylla (Raf.) Sarg. were studied throughout the annual growth cycle. Apices become mitotically active during the last week of March. Leaf primordia elongate, causing the buds to swell, while the apex remains small and produces bud scales. Axillary buds are initiated about mid-April. Little shoot elongation occurs before vegetative buds burst in mid-May. After bud burst, rapid shoot elongation occurs for about 7 weeks, during which time the apex also elongates and the rest of the bud scales are initiated. There is a marked increase in mitotic activity in the apex during the transition from bud-scale initiation to leaf initiation, which occurs early in July when the grand phase of shoot elongation is complete. This is believed to be the time when vegetative apices undergo transition to become reproductive apices. Leaf primordia are initiated in rapid succession until mid-August, when two-thirds of the final number of leaves are initiated and the subtending shoot is fully elongated. From mid-August until mid-November, no shoot elongation occurs, leaf primordia are initiated more slowly, and mitotic activity in the apex gradually decreases. After all of the next season's leaves have been initiated, about mid-November, mitotic activity in the apex stops and the vegetative buds become dormant.

Bud development in coastal Douglas-fir seedlings in response to different dormancy-induction treatments

1993 ◽  
Vol 71 (10) ◽  
pp. 1280-1290 ◽  
Author(s):  
Joanne E. MacDonald ◽  
John N. Owens
Keyword(s):  
Cell Walls ◽  
Moisture Stress ◽  
Douglas Fir ◽  
Bud Development ◽  
Stress Treatment ◽  
Leaf Initiation ◽  
Short Day ◽  
Long Day ◽  
Dormancy Induction ◽  
Short Days

Bud development in response to different dormancy-induction treatments in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) seedlings was investigated under commercial greenhouse conditions. There were three treatments: short day without moisture stress, short day with moisture stress, and long day with moisture stress. Within the first week in the short day treatments, neoformed-leaf initiation ended and bud-scale initiation began and ended. Rapid leaf initiation began in week 1 and was completed by week 5 for the short day with moisture stress treatment and week 6 for the short day without moisture stress treatment. Slow leaf initiation was completed by week 13. Crown cells became apparent within the pith during weeks 3–6; cell walls thickened between weeks 8 and 13. Within the first week of the long day with moisture stress treatment, neoformed-leaf initiation ended and bud-scale initiation began. Bud-scale initiation ended by week 3 or 4. Then slow leaf initiation began and continued until week 6. Rate of leaf initiation was rapid during weeks 8–10 and decreased slightly during weeks 10–13. By week 13, apical height had decreased markedly, indicating an imminent end to leaf initiation. Crown cells became apparent within the pith during weeks 5–13; cell walls thickened between weeks 10 and 13. Key words: bud development, dormancy induction, short days, moisture stress, Douglas-fir, seedlings.

Influence of dormancy induction treatments on western hemlock seedlings. II. Physiological and morphological response during the first growing season on a reforestation site

1991 ◽  
Vol 21 (2) ◽  
pp. 175-185 ◽  
Author(s):  
S. C. Grossnickle ◽  
J. T. Arnott ◽  
J. E. Major
Keyword(s):  
Low Temperature ◽  
Root Development ◽  
Growing Season ◽  
Western Hemlock ◽  
Root Collar Diameter ◽  
Short Day ◽  
Long Day ◽  
Collar Diameter ◽  
Root Collar ◽  
Dormancy Induction

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings from four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, short-day wet) were planted on a coastal reforestation site in British Columbia and monitored for physiological response and morphological development over the first growing season. Seedlings in all DIT showed a similar net photosynthetic, needle conductance, and shoot water potential response to seasonal low temperature, non droughty, and late summer drought conditions. Pressure–volume analysis at the beginning of the growing season (late February) showed short-day wet seedlings to have lower saturated and turgor loss point osmotic potentials than other DIT, while at the end of the growing season (October) there was no osmotic potential difference between DIT. At the end of the growing season, short-day wet seedlings had a much lower maximum modulus of elasticity than other DIT, indicating their shoots were still elongating. Morphological assessment 1 month after field planting showed short-day DIT seedlings had less needle damage and greater root development in response to continuous low temperature exposure. Four months after planting, long-day wet seedlings had the greatest shoot (i.e., height, root collar diameter) and root development in response to mild temperatures and high soil moisture conditions. Eight months after planting, survival was between 95 and 97% for all DIT. Long-day DIT seedlings had the greatest height and all DIT had similar root collar diameter and root development. Short-day DIT seedlings had the best shoot/soil roots ratio. Short-day wet seedlings had the least number of stem units per centimetre of new shoot development throughout the growing season. Results are discussed in reference to stock quality assessment presented in the first paper of this series.

Bud development in coastal Douglas-fir seedlings under controlled-environment conditions

1993 ◽  
Vol 23 (6) ◽  
pp. 1203-1212 ◽  
Author(s):  
Joanne E. MacDonald ◽  
John N. Owens
Keyword(s):  
Moisture Stress ◽  
Douglas Fir ◽  
Controlled Environment ◽  
Crown Height ◽  
Bud Development ◽  
Leaf Initiation ◽  
Short Day ◽  
Two Stages ◽  
Transitional Phase ◽  
Dormancy Induction

Bud development under controlled-environment conditions in coastal Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) seedlings was investigated. In eight dormancy induction treatments, type of short, day, temperature, and moisture varied. Photoperiod was decreased to 8 h either abruptly (abrupt short day) or gradually (gradual short day). Temperature was either constant at a high temperature or gradually decreased to a low temperature. Moisture was controlled either to result in no moisture stress or to cause moisture stress. Once a dormancy induction signal was perceived by seedlings, neoformed-leaf initiation stopped and bud development began. Bud development involved two stages of primordial initiation (bud scale and leaf) separated by a transitional phase. The change from neoformed-leaf to bud-scale initiation was faster, fewer bud scales were initiated, and the development of the bud-scale complex was faster under abrupt short day than under gradual short day. The transitional phase was shorter and hence leaf initiation began earlier under abrupt short day than under gradual short day and under no moisture stress than under moisture stress. More leaf primordia were initiated under abrupt short day than under gradual short day and under no moisture stress than under moisture stress. The bud-scale receptacle was concave under abrupt short day and convex under gradual short day. Crown height was greater under abrupt short day than under gradual short day.

Flowering in a jack pine seedling seed orchard increased by spraying with gibberellin A4/7

1983 ◽  
Vol 13 (6) ◽  
pp. 1056-1062 ◽  
Author(s):  
Robert A. Cecich
Keyword(s):  
Growing Season ◽  
Seed Orchard ◽  
Shoot Elongation ◽  
Jack Pine ◽  
Ethanol Solution ◽  
Bud Development ◽  
Seedling Seed Orchard ◽  
Female Flowering ◽  
Accelerated Growth ◽  
Control Tree

Jack pine (Pinusbanksiana Lamb.), in a 3-year-old orchard established with accelerated-growth seedlings, were sprayed with gibberellin A4/7 (GA4/7) in an Aromox–ethanol solution during the 1981 growing season. Seven treatment periods were evaluated: the entire growing season, shoot elongation, bud development, early (first half) and late (second half) shoot elongation, and early and late bud development. Three concentrations of GA4/7 (200, 400, and 600 mg•L−1) were applied in all combinations with treatment periods. Three treatments increased female flowering: 400 and 600 mg•L−1 GA4/7 sprayed the entire growing season and 600 mg•L−1 sprayed during bud development. The number of pollen clusters was increased by spraying 400 and 600 mg•L−1 GA4/7 during any treatment period except early shoot elongation and late bud development or during shoot elongation (400 mg•L−1 only). The 200 mg•L−1 GA4/7 increased pollen clusters only if sprayed during early bud development or the entire growing season. The percentage of trees bearing pollen increased with all concentrations of GA4/7. The 1982 shoot growth of trees sprayed in 1981 during shoot elongation or the entire growing season (all GA4/7 levels pooled) was significantly less than control-tree growth or that of trees in the other treatment periods. The best treatment for increasing both male and female strobili was 600 mg•L−1 GA4/7 sprayed during bud development.

scholarly journals Morphology, Physiology, Survival, and Field Performance of Containerized Coastal Douglas Fir Seedlings Given Different Dormancy-induction Regimes

HortScience ◽  
2006 ◽  
Vol 41 (6) ◽  
pp. 1416-1420 ◽  
Author(s):  
Joanne E. MacDonald ◽  
John N. Owens
Keyword(s):  
Seedling Survival ◽  
Dry Weight ◽  
Growing Season ◽  
Moisture Stress ◽  
Root Collar Diameter ◽  
Shoot Dry Weight ◽  
Collar Diameter ◽  
Terminal Buds ◽  
Root Collar ◽  
Dormancy Induction

The effects of different dormancy-induction regimes on first-year containerized coastal Douglas fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] seedling morphology and physiology in the nursery, as well as seedling survival and performance after one growing season in a common garden, were investigated. In early July, three dormancy-induction regimes were applied: moderate moisture stress (MS), short day (SD), and short day with moderate moisture stress (SD+MS). In early October, seedling height, root collar diameter, and shoot dry weight were unaffected by regime, but root dry weight was reduced in seedlings from the MS and SD+MS regimes compared with the SD regime. At this time, morphogenesis was completed in all terminal buds of seedlings from both SD regimes, whereas it continued in all terminal buds of seedlings from the MS regime. Furthermore, 25% to 88% of terminal buds from the SD regimes were endodormant, but none from the MS regime were endodormant. In March, budbreak occurred at the same time in seedlings from the two SD regimes and was earlier than in seedlings from the MS regime; root growth capacity was unaffected by regime. After one growing season, there were no regime differences in seedling survival, root collar diameter, shoot dry weight, root dry weight, length of the current-year leader, or number of needles on the leader.

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.

The effects of summer shoot production on height growth components of seedlings of California red and white fir

1992 ◽  
Vol 22 (5) ◽  
pp. 690-698 ◽  
Author(s):  
Stephen W. Hallgren ◽  
John A. Helms
Keyword(s):  
Soil Moisture ◽  
Growing Season ◽  
Shoot Elongation ◽  
Height Growth ◽  
Shoot Morphology ◽  
Apical Dome ◽  
White Fir ◽  
Shoot Production ◽  
Terminal Shoot ◽  
Needle Primordia

Morphogenesis of the terminal shoot was studied in 2-year-old seedlings of California red fir (Abiesmagnifica A. Murr.) and two elevational sources of white fir (Abiesconcolor (Gord. & Glend.) Lindl.). Seedlings were either watered or left unwatered during the growing season in order to produce different shoot morphologies and seedlings with and without a summer shoot. Under favorable soil moisture, the frequency of summer shoot production was 32, 53, and 82% for red fir and high- and low-elevation white fir, respectively. Drought from mid-May to mid-September reduced summer shoot production to less than 1% in both species. Spring shoot morphology was not an indicator of capacity to produce a summer shoot. Rate of primordium production was directly related to apical dome diameter. However, when the normal spring increase in apical dome diameter was arrested by summer shoot elongation, the rate of primordium production appeared to be unaffected. Although the apical and subapical meristems were active at the same time, they did not appear to be antagonistic. The major effects of producing a summer shoot were as follows: (i) elongation of 60–120% more intemodes in the current growing season, (ii) production of 15–40% more needle primordia in the overwintering bud, (iii) production of 30–60% more primordia annually, and (iv) increase in the percentage of total primordium production that developed into needles from 60% to 75–80%.

The Influence of Fruit and Bud Volumes on Eucalypt Flowering—An Exploratory Analysis

1998 ◽  
Vol 46 (2) ◽  
pp. 281 ◽  
Author(s):  
Marie R. Keatley ◽  
Irene L. Hudson
Keyword(s):  
Factor Analysis ◽  
Discriminant Analysis ◽  
Development Time ◽  
Growing Season ◽  
Exploratory Analysis ◽  
Large Individual ◽  
Bud Development ◽  
Seed Maturity ◽  
Development Period

The appearance of buds and development of fruits in 51 species of Eucalyptus L’Hér. were examined to determine whether bud and fruit volume had an influence on flowering. These variables exert an influence on eucalypt flowering as individuals and as members within an umbel. Flowering earlier in the growing season is characteristic of species with large, individual bud and fruit volume and those that have a large umbel volume. The number of buds and fruits in an umbel is influenced by volume of the individuals. Development time of buds was longer in umbels which had a larger total volume. Bud and fruit umbel volume was positively correlated with the timing of bud appearance as was seed maturity with individual fruit and fruit umbel volume. A threshold of bud and fruit volume was indicated below which seed maturity and time of flowering is not reflected by volume. Discriminant analysis used nine predictors to assign 80% (overall) of section members of Adnataria (91%), Bisectaria (60%), Maidenaria (67%) and Renantheria (87%) to their true groups. Across groups examination adduced the possibility of each group having a distinct bud development period and a discernible cessation of flowering. Five clusters were revealed whose members were significantly differentiated on seed maturity, section, individual fruit volumes, bud and fruit umbel volumes. Factor analysis outlined four factors—buds, fruits, timing and development—which accounted for 78.9% of the variance.

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