Bud morphogenesis of white spruce Picea glauca seedlings in a uniform environment

1974 ◽  
Vol 52 (7) ◽  
pp. 1569-1571 ◽  
Author(s):  
D. F. W. Pollard

Differences in height growth occurring between provenances of white spruce are associated with variation in number of needle primordia formed in the dormant bud. The number is influenced by seasonal pattern of initiation. This investigation sought to establish whether normal morphogenesis could proceed in a constant environment, and whether provenance variation would be expressed in the absence of seasonal changes. Bud development was induced in five provenances of white spruce by subjecting 1st-year seedlings to short photoperiods. Developing buds were sampled at 3-week intervals over a period of 12 weeks. Throughout this time, photoperiod was kept at 8 h; temperature was constant at 22.5 °C (72.5 °F). Observations revealed a morphogenetic pattern comparable with that of buds in older, field-grown trees. Needle initiation on the primordial shoot ceased 6 to 12 weeks after the inception of bud development. The inferred endogenous control of bud development and its effect on shoot growth was influenced genetically, with significant differences in needle initiation occurring among the provenances. Differences in bud development may allow early selection for fast growth and hardiness in this species. The results of this investigation identify the period immediately after shoot growth as critical for subsequent growth of nursery stock.

1992 ◽  
Vol 70 (7) ◽  
pp. 1488-1492 ◽  
Author(s):  
Peter Nosko ◽  
Kenneth A. Kershaw

Week-old white spruce seedlings were grown for 7 days at pH 4.5, 3.9, 3.65, or 3.5 using a continuous flow system to deliver experimental solutions. At each pH, seedlings received either no aluminum or 10 μM Al, a concentration 2 – 3 orders of magnitude lower than the reported minimum Al concentrations required to induce toxicity symptoms in seedlings of a variety of tree species. In – Al treatments, root elongation was reduced at pH 3.9 and root dry weight was reduced at pH 3.5, compared with seedlings grown at pH 4.5. Exposure to 10 μM Al caused further reduction of root growth, the magnitude of which increased as pH decreased. This suggests that seedling root growth was affected by the increased proportion of the total Al existing as phytotoxic Al3+ at lower pH values or by an interaction of Al3+ and H+. Neither pH nor Al affected shoot growth. Both acidity and Al could limit natural regeneration of white spruce by preventing seedling establishment. Key words: aluminum toxicity, soil acidity, forest decline, white spruce, Picea glauca, forest regeneration.


1998 ◽  
Vol 28 (3) ◽  
pp. 418-426 ◽  
Author(s):  
Michael U Stoehr ◽  
Sylvia J L'Hirondelle ◽  
Wolfgang D Binder ◽  
Joe E Webber

Seed orchards for the production of conifer seed in British Columbia are usually located in areas favorable (warm and dry) for flowering and seed development, often considerably south of the source location of the parent trees. Differences in environmental conditions between seed orchard location and location of origin can affect progeny performance. It is suspected that this is caused by environmental factors that affect reproductive processes of parent trees and lead to altered physiological traits (aftereffects). This study examined if aftereffects are present in white spruce (Picea glauca (Moench) Voss). Control pollinations were made at two locations, Red Rock, near Prince George (53°N) in central British Columbia, and Kalamalka, near Vernon (50°N) in southern British Columbia, on five female trees using a four-male polymix. Identical genotypes through grafting were present at the two locations. Pollen maturing at each site was only used in the polymix at that particular location. Progeny were raised and germination traits, number of needle primordia, greenhouse and field heights, and frost hardiness were evaluated in a common environment. The location of seed development significantly affected all traits evaluated. Height growth aftereffects in the second field season were much less than those observed in the first field season. These results suggest that aftereffects are detectable in white spruce progeny performance in British Columbia.


1967 ◽  
Vol 43 (2) ◽  
pp. 155-160 ◽  
Author(s):  
R. E. Mullin

Two lots of 2-0 white spruce (Picea glauca (Moench) Voss) in soil blocks were brought into the greenhouse in February. The first lot, called "active" was left in the greenhouse for 10 days before transplanting. The second lot, called "dormant" was left in the greenhouse for 3 days before transplanting. The seedlings were then washed from the soil, graded, and exposed to the air on nets, some in the greenhouse, some in an adjacent laboratory. The exposure varied from 0 (immediate planting), to ½, 1, 1½, 2 and 2½ hours. After planting, the seedlings were grown in the greenhouse for four months, then removed from the soil and measured.The results showed greater mortality from root exposure of the "active" seedlings. The mortality increased with the length of exposure. Growth also was inhibited most within the "active" stock. However, growth was reduced even in the "dormant" stock by root exposures of ½ hour or longer. Differences due to location in greenhouse or laboratory during root exposure were not significant.


1965 ◽  
Vol 41 (1) ◽  
pp. 108-111 ◽  
Author(s):  
R. F. Sutton

Three ½-oz. spot applications of Dybar (pelleted fenuron: 3-phenyl-1, 1-dimethylurea) were given in 1960-61 to competing vegetation around each planted white spruce (Picea glauca (Moench) Voss) in an overmature boreal mixedwood. The herbicide was applied at distances from 1 to 7 feet from the spruce concurrently with planting, in fall, spring and summer. Survival of white spruce, 75 per cent in 1963, was not affected significantly by any of the treatments. A highly significant relationship was found between total live canopy in 1963 (X, not greater than 75%) and height growth of spruce in 1963 (Y):[Formula: see text]Significance of regression was not increased by the inclusion of either initial canopy or height of stock at planting. The study shows that the non-selective Dybar can safely be used at the time of planting to aid the establishment of white spruce, and that subsequent growth of the spruce is largely dependent on the density of total live canopy.


1975 ◽  
Vol 5 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Douglas F. W. Pollard ◽  
Abraham H. Teich ◽  
Kenneth T. Logan

Growth and development of seedlings of ten provenances were compared in three investigations. The provenances ranged from Oregon to south-east Alaska and were collected for the I.U.F.R.O. International Sitka Spruce Provenance Experiment. The potential for seedling growth was studied by measuring (a) the rate of shoot growth and (b) the duration of shoot elongation. Growth rate was rather uniform, being only slightly faster among northern provenances. The duration of shoot growth, under artificial declining photoperiods was strongly influenced by latitude of origin. The critical photoperiods necessary for sustained growth in southern provenances were up to 4 hours shorter than those in northern provenances. In the third investigation development of the terminal bud was followed during the first 8 weeks. After a 4-week induction period buds attained macroscopic sizes with ca. 100 needle primordia. Northern provenances had up to 65% more primordia than southern ones. At 8 weeks, a strong but reversed relationship was evident, with southern provenances having up to 35% more than northern provenances. These observations indicate that latitude-correlated variations will be an important feature of the I.U.F.R.O. Experiment, with southern provenances performing especially well in southern trials. Potential advantages of southern provenances will be protracted periods of shoot growth in young seedlings and protracted periods of development of the primordial shoot in overwintering buds. However, where summer seasons are short, such advantages may not be realized.


1977 ◽  
Vol 55 (21) ◽  
pp. 2728-2745 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder ◽  
Hilary Langer

Vegetative buds of Picea glauca (Moench) Voss were studied throughout the annual growth cycle in several trees in 1975 and 1976 and bud development was related to lateral vegetative shoot growth, date, and temperature sums.Vegetative buds became mitotically active in mid-April at lower elevations and about 6 weeks later at higher elevations. Shoot elongation was characterized by similar smooth sigmoid curves in both years. Shoot growth was slow for the 1st month, rapid during the 2nd month, and slow again for the 3rd month and ended by early August. Temperature sums related best to percentage of shoot elongation if the end of vegetative bud dormancy was used as the starting date and 5 °C was used as the threshold temperature. Arbitrarily chosen starting dates and threshold temperatures gave temperature sums which were related to shoot elongation only when shoot elongation was nearly completed. Generally, if the end of vegetative bud dormancy is known, the number of days from that time is nearly as accurate as the more complex use of temperature sums in predicting the percentage of shoot elongation or the stage of vegetative bud development.Bud-scale initiation occurred during shoot elongation. Axillary buds were initiated in mid-May and flushing occurred when shoots had elongated to about 30% of their final length in late May or early June. The end of shoot elongation coincided with the onset of leaf initiation on all trees in both years. The change from bud-scale initiation to leaf initiation was preceded by a marked increase in apical width and a slight increase in apical height and mitotic frequency. Leaf initiation was rapid for 6 weeks then slower for the last 4 weeks. Vegetative buds became dormant in mid-October.Vegetative bud development is closely related to shoot elongation. Breaking of vegetative bud dormancy was not affected by temperature but shoot elongation and flushing were affected by temperatures which occurred after dormancy was broken.


2001 ◽  
Vol 31 (12) ◽  
pp. 2200-2212 ◽  
Author(s):  
Debra C Stowe ◽  
Mohammed S Lamhamedi ◽  
Hank A Margolis

White spruce seedlings (Picea glauca (Moench) Voss) were grown in air-slit containers (IPL 25-350A) in a tunnel under four different irrigation regimes (IR-15%, IR-30%, IR-45%, and IR-60%, v/v; (cm H2O)3·(cm substrate)–3). At the end of the first growing season the water-relation variables of the shoots were determined. Seedling morphology, the rates of cuticular transpiration and terminal bud development, as well as the number of needle primordia were also measured. Irrigation regime had no significant effect on any of the water-relation variables. Seedlings grown under the IR-15% were smaller and completed bud development more quickly than seedlings grown under IR-30%, IR-45%, and IR-60%. The formation of needle primordia was enhanced under IR-30%. Both the irrigation regime and the amount of time the detached shoots were left to transpire had a significant effect on the rate of cuticular transpiration. A comparison of the water-relation variables at the end of the first (1998) and second (1999) growing seasons showed that the younger seedlings had more negative osmotic potential at tissue saturation and greater maximum modulus of elasticity values. None of the other water-relation variables were significantly affected by seedling age, but the absolute values of all the variables were greater in the younger (1+0) seedlings.


1966 ◽  
Vol 42 (3) ◽  
pp. 256-264 ◽  
Author(s):  
R. E. Mullin

In the fall of 1958, an experiment was begun at Midhurst Nursery to study the effects of root pruning at different stages of growth and at two depths, on 3-0 stock of white spruce (Picea glauca (Moench) Voss) and white pine (Pinus strobus L.). Root pruning was done by undercutting broadcast-sown seedbeds at two inch and four inch depths; in the fall as 2-0 (Sept. 16, 1958), in the spring at start of growth (April 30, 1959), during flush of growth (May 28, 1959) and towards end of terminal growth (June 25,1959).Seedbed counts were taken before lifting, in fall 1959, to study mortality. Random samples were taken on date of lifting (Sept. 17, 1959), for laboratory measurements to study effects on seedlings size. Other random samples were planted in experimental designs at Larose Forest. Counts of survival, and measurements of terminal growth were taken at the first, third and fifth year after planting.Results showed no mortality in the nursery but that all root pruning reduced height growth. Root pruning of white spruce after the flush of growth (June 25) increased survival and growth after outplanting, over that of unpruned stock. None of the treatments increased survival or growth of white pine. Depth of root pruning had no significant effect.


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