The relative importance of initiation and early development on cone production in Douglas fir

1969 ◽  
Vol 47 (7) ◽  
pp. 1039-1049 ◽  
Author(s):  
John N. Owens
Keyword(s):  
Vegetative Growth ◽  
Succinic Dehydrogenase ◽  
Douglas Fir ◽  
Relative Importance ◽  
Succinic Dehydrogenase Activity ◽  
Cyclic Pattern ◽  
Cone Production ◽  
Lateral Buds ◽  
Lateral Bud ◽  
Bud Initiation

Lateral bud initiation as determined by increased succinic dehydrogenase activity in the axils of certain leaves occurs by April 1 in the Victoria area. The number of lateral buds initiated did not vary significantly in 1967 and 1968 while the number of buds which developed did. Not all primordia which are initiated develop. Some abort very early and disappear completely while others develop bud scales then cease development and become latent. The rest of the primordia fully develop as vegetative, male, or female buds. In 1967 when abundant cones developed, 56% of the primordia fully developed and most of these became reproductive buds. In 1968 when no cones developed, only 31% of the primordia fully developed and all of these became vegetative. The number of cones produced was, therefore, not determined directly by the number of primordia initiated but by the proportion of primordia which developed as reproductive buds. The presence of abundant maturing cones on shoots formed the previous year greatly reduces the number of primordia which develop and, also, reduces the possibility of these becoming reproductive buds. Previous vegetative growth and cone crops affect the cone productivity in subsequent years and help explain the cyclic pattern of reproduction in Douglas fir.

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.

Cone Production of Douglas-fir and Grand Fir and its Climatic Requirements

1973 ◽  
Vol 3 (1) ◽  
pp. 61-70 ◽  
Author(s):  
S. Eis
Keyword(s):  
Climatic Factors ◽  
Douglas Fir ◽  
Climatic Variables ◽  
Successful Development ◽  
Bud Development ◽  
Cone Production ◽  
Cloudy Weather ◽  
Sunny Weather ◽  
June July ◽  
Bud Initiation

Thirty-six-year records of Douglas-fir and grand fir cone counts were analyzed with eight climatic variables to find which combinations of climatic factors were related to the induction of reproductive buds and the successful development of the strobili. Cool, cloudy weather during June, July, and August, 26–24 months before cone maturation, was the first prerequisite for abundant reproductive bud initiation. The second was cold, sunny weather during December, January, and February, 20–18 months before cone maturation. A wet April, 16 months before cone maturation, resulted in a higher proportion of megasporangiate strobili being differentiated, while a warm, dry, sunny June, 14 months before cone maturation, favored successful bud development. Since the prerequisites for a good cone crop include an alternation of cool, moist summers (2 years prior) and warm, dry summers (1 year prior), good cone crops in two consecutive years can not be expected. And since additional environmental prerequisites must be fulfilled, a lapse of several years between good cone crops is probable.

Histology and histochemistry of elongating needles of Pinus strobus subjected to a long-duration, low-concentration exposure of sulfur dioxide

1981 ◽  
Vol 59 (12) ◽  
pp. 2558-2567 ◽  
Author(s):  
K. E. Percy ◽  
R. T. Riding
Keyword(s):  
Growth Parameters ◽  
Succinic Dehydrogenase ◽  
Pinus Strobus ◽  
Wall Region ◽  
Growth Reduction ◽  
Succinic Dehydrogenase Activity ◽  
Long Duration ◽  
Bud Set ◽  
Total Carbohydrates ◽  
External Growth

Two-year-old seedlings of Pinus strobus were grown from budbreak to bud set (11 weeks) in air containing 132 ± 26 μg SO2∙m−3. Histological and histochemical effects on elongating needles were examined. Cellular injury was restricted to mesophyll parenchyma. Affected cells manifested a progressive alteration of protoplast staining proportional to the degree of injury. Total carbohydrates and plastids aggregated at cell walls. Total proteins and proteins containing sulfhydryl–disulfide groups decreased. Phospholipid staining in the plasmalemma – cell wall region appeared reduced. Succinic dehydrogenase activity was enhanced and was apparent longer in injured cells. Needle ontogeny was slowed in fumigated seedlings. There were no significant differences in external growth parameters after 11 weeks. The injury can, therefore, be classified as latent or hidden. The SO2 effects could contribute to a growth reduction in successive increments.

Cost of reproduction in Douglas-fir

1992 ◽  
Vol 70 (7) ◽  
pp. 1429-1432 ◽  
Author(s):  
Yousry A. El-Kassaby ◽  
Hugh J. Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Annual Ring ◽  
Ring Width ◽  
Energy Allocation ◽  
Douglas Fir ◽  
Environmental Correlations ◽  
Annual Ring Width ◽  
Trade Off ◽  
Cone Production ◽  
Seed Cone

The balance between allocating energy resources to reproduction or growth has considerable theoretical interest. Conflicting ecological requirements and evolutionary pressures often necessitate a trade-off in energy allocation. We obtained measurements on seed-cone production and annual ring width of 365 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from 29 open-pollinated families for 8 years. Phenotypic, genetic, and environmental correlations were computed for seed-cone production and ring width for each year. Five of the eight environmental correlations were negative (range −0.077 to −0.305), reflecting the reality of the trade-off in physiological terms. Six of the eight genetic correlations were negative (range −0.199 to −0.776), indicating that a trade-off exists at the genetic level between energy allocation to reproduction and to somatic growth. These findings agree with the current theory of life-history evolution. Key words: Pseudotsuga menziesii, cone production, annual ring width, genetic correlation.

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