Pollen scavenging and rain involvement in the pollination mechanism of interior spruce

1996 ◽  
Vol 74 (1) ◽  
pp. 115-124 ◽  
Author(s):  
C. John Runions ◽  
John N. Owens
Keyword(s):  
Picea Glauca ◽  
Selective Pressure ◽  
Seed Orchard ◽  
Picea Engelmannii ◽  
Pollination Efficiency ◽  
Pollination Mechanism ◽  
Pollination Mechanisms ◽  
Seed Cone ◽  
Interior Spruce ◽  
Pollination Drop

Pollination drops are secreted from the ovules of interior spruce (Picea glauca or Picea engelmannii and their hybrid) as seed cones begin to close at the end of the pollination period. Secreted pollination drops persist within spaces surrounding the micropylar opening in closed seed cones. Saccate pollen floats into the micropyle within the pollination drop. Pollination drops become voluminous enough, within the enclosed spaces, to scavenge pollen adhering to the micropylar arms and other surfaces in proximity with the micropyle. Scavenging of pollen from cone surfaces adjacent to the integuments is sometimes facilitated by rainwater that can float pollen into the opening of the micropyle before cone closure and pollination drop secretion. In practice, periodic, light misting of seed orchard trees during seed cone receptivity might increase pollination efficiency by mimicking rainwater involvement in the pollination mechanism. Rainwater involvement in pollination of some modern conifers may reflect a similar situation in the pollination mechanisms of ancestral conifers. Environments with limited rainfall combined with the requirement for moisture in the pollination mechanism may have provided the selective pressure for evolution of the pollination drop. Keywords: pollination drop, Picea, conifer, sacci.

Pollination mechanism of seed orchard interior spruce

1995 ◽  
Vol 25 (9) ◽  
pp. 1434-1444 ◽  
Author(s):  
C. John Runions ◽  
Glenda L. Catalano ◽  
John N. Owens
Keyword(s):  
Temporal Correlation ◽  
Seed Orchard ◽  
Pollination Mechanism ◽  
Pollination Success ◽  
Engelmann Spruce ◽  
Interior Spruce ◽  
Pollination Drop ◽  
Cone Development ◽  
Dry Conditions ◽  
Natural Range

The pollination mechanism of interior spruce (white spruce, Piceaglauca (Moench) Voss, or Engelmann spruce, Piceaengelmannii Parry, and their hybrid) trees growing in a seed orchard was studied. Seed orchards are established in areas that are warmer and drier than the parent tree natural range. Hot, dry conditions during the pollination period adversely affected secretion of the pollination drop in unbagged seed cones as compared with bagged cones on the same tree. Unbagged cones remained open and apparently receptive for pollination for 5.3 ± 1.6 days (100 ± 31 h at >10°C), but pollination drops did not appear during this period. Pollination drops were secreted as cones began to close. The temporal correlation observed between cone closure and pollination drop secretion occurred as well in the higher relative humidity environment within pollination bags. Pollination drops in unbagged cones were smaller and did not persist as long as those in bagged cones. The micropylar arms, which capture pollen prior to pollination drop secretion, withered completely in unbagged cones before pollination drops were observed. Some withering of micropylar arms during cone receptivity is natural but complete withering means that the arms can not function in pollen capture throughout the period during which cones remain open. For this reason, supplemental mass pollination is best carried out early during the receptive period for trees growing in hot, dry environments. Overhead misting, used periodically during the receptive period to cool orchard trees, might slow seed-cone development and reduce micropylar arm withering, thereby increasing pollination success after supplemental mass pollination.

Frost hardiness, height, and dormancy of 15 short-day, nursery-treated interior spruce seed lots

2000 ◽  
Vol 30 (7) ◽  
pp. 1096-1105 ◽  
Author(s):  
C DB Hawkins ◽  
K B Shewan
Keyword(s):  
Picea Glauca ◽  
Day Treatment ◽  
Field Performance ◽  
Seed Orchard ◽  
Frost Hardiness ◽  
Control Treatment ◽  
Short Day ◽  
Physiological Processes ◽  
Interior Spruce ◽  
Day Nursery

Fifteen seed lots, five each from natural-stand, seed-orchard, and full-sib collections, of interior spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm., and their naturally occurring hybrids) were sown in February 1993. One half of each seed lot received an ambient photoperiod (control) treatment, while the other half got a blackout (short-day) treatment. All seedlings were grown under ambient photoperiod except during the 17 days of blackout. Frost hardiness assessments were done between July and May. Blackout treatment was effective in regulating height and promoting frost hardiness in all seed lots, particularly vigorous ones. Seed lots originating from high latitude or elevation were more frost hardy both at fall lift and spring planting. Full-sib seed lots from similar latitude displayed no elevational frost-hardiness trend. Blackout treatment promoted seedling dormancy (estimated with days to bud break) at lift, but it had little or no effect on dormancy at planting. Seedling dormancy and frost hardiness were acquired and lost differently, suggesting that they are independent physiological processes. Blackout treatment significantly reduced new roots at planting in all lots. This could retard early field performance and negate the apparent utility of blackout treatment.

Area-based breeding zones to minimize maladaptation

2004 ◽  
Vol 34 (3) ◽  
pp. 695-704 ◽  
Author(s):  
Gregory A O'Neill ◽  
Sally N Aitken
Keyword(s):  
Cluster Analysis ◽  
Picea Glauca ◽  
Grid Cell ◽  
Picea Engelmannii ◽  
Breeding Programs ◽  
Adaptive Value ◽  
Interior Spruce ◽  
Breeding Zone ◽  
Abc Analysis ◽  
Predetermined Number

A new breeding zone delineation scheme identifies for a given number of zones the zone-boundary placement that minimizes regional maladaptation in breeding programs. First, an adaptive map is created by using conventional genetic test data. Then, the large array of predicted adaptive values is subjected to cluster analysis, which assigns each grid cell of the region to one of a predetermined number of clusters (breeding zones) such that the sum of the squared distances between each cell's adaptive value and its cluster mean is minimized. This approach minimizes the average adaptive distance between the origin of a breeding program's selected trees and planting locations throughout the region of focus. The procedure is illustrated by the use of adaptive values of 69 interior spruce (Picea engelmannii Parry ex Engelm. × Picea glauca (Moench) Voss) open-pollinated families (sources) from southeast British Columbia, Canada. Adaptive values of each 1.5 km × 1.5 km grid cell in the 80 000-km2 region were predicted using a geneco logical model (R2 = 0.64), and the values were subjected to cluster analysis to identify breeding zone boundaries that were then mapped using a geographic information system. Regardless of the number of zones created, a regional maladaptation index was consistently smaller when zones were devised with area-based cluster (ABC) analysis than when zones were created by dividing the region into bands of equal elevational or adaptive-value widths. Application of the ABC procedure should assist in identifying the optimum breeding-zone alignment for a given number of zones.

Taxonomy and origin of present-day morphometric variation in Picea glauca (×engelmannii) seed-cone scales in North America

2006 ◽  
Vol 84 (7) ◽  
pp. 1129-1141 ◽  
Author(s):  
W.L Strong ◽  
L.V. Hills
Keyword(s):  
Rocky Mountains ◽  
Picea Glauca ◽  
White Spruce ◽  
Black Hills ◽  
Picea Engelmannii ◽  
Morphometric Variation ◽  
Engelmann Spruce ◽  
Seed Cone ◽  
Northern United States ◽  
Cone Scale

White spruce ( Picea glauca (Moench) Voss) and Engelmann spruce ( Picea engelmannii Parry ex Engelm.) seed-cones from 676 sites in Canada and the northern United States were analyzed to determine the degree and spatial extent of interspecific hybridization. Fifteen cone-scale variables were analyzed, with percent free-scale and scale shape considered best for differentiating these taxa. The results show that putative Engelmann spruce and their hybrids occur mostly in the vicinity of the Rocky Mountains. Putative white spruce occurs across Canada east of the Rocky Mountains, whereas white × Engelmann hybrids occur eastward to Manitoba and northward to 68° latitude in northwest Canada. To explain the occurrence of the latter taxon hundreds of kilometres from an Engelmann spruce pollen source, it is hypothesized that palaeohybridization occurred during the Wisconsinan glacial period, probably in the southern Montana – Wyoming – Black Hills (South Dakota) region, with the resulting hybrids spreading north and northeastward into interior Canada following the retreat of the Laurentide glacier. White and Engelmann spruce have morphologically distinct cone-scales, whereas their hybrids have intermediate characteristics. An emended species ( Picea albertiana ) and two subspecies (P. albertiana subsp. albertiana and P. albertiana subsp. ogilviei) are proposed to account for morphological intermediates between the parent species.

Conservation and divergence of gene expression plasticity followingc. 140 million years of evolution in lodgepole pine (Pinus contorta) and interior spruce (Picea glauca × Picea engelmannii)

2014 ◽  
Vol 203 (2) ◽  
pp. 578-591 ◽  
Author(s):  
Sam Yeaman ◽  
Kathryn A. Hodgins ◽  
Haktan Suren ◽  
Kristin A. Nurkowski ◽  
Loren H. Rieseberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Picea Engelmannii ◽  
Interior Spruce

Polyamine biosynthesis during somatic embryogenesis in interior spruce (Picea glauca x Picea engelmannii complex)

1996 ◽  
Vol 15 (7) ◽  
pp. 495-499 ◽  
Author(s):  
Vindhya Amarasinghe ◽  
Rajwinder Dhami ◽  
John E. Carlson
Keyword(s):  
Somatic Embryogenesis ◽  
Picea Glauca ◽  
Picea Engelmannii ◽  
Polyamine Biosynthesis ◽  
Interior Spruce

Polyamine biosynthesis during somatic embryogenesis in interior spruce (Picea glauca�Picea engelmannii complex)

1996 ◽  
Vol 15 (7) ◽  
pp. 495-499 ◽  
Author(s):  
Vindhya Amarasinghe ◽  
John E. Carlson ◽  
Rajwinder Dhami
Keyword(s):  
Somatic Embryogenesis ◽  
Picea Glauca ◽  
Picea Engelmannii ◽  
Polyamine Biosynthesis ◽  
Interior Spruce

The pollination mechanism of Engelmann spruce (Picea engelmannii)

1987 ◽  
Vol 65 (7) ◽  
pp. 1439-1450 ◽  
Author(s):  
John N. Owens ◽  
Sheila J. Simpson ◽  
Guy E. Caron
Keyword(s):  
Seed Set ◽  
Picea Engelmannii ◽  
Diurnal Fluctuation ◽  
Secretory Cells ◽  
Controlled Environment ◽  
High Humidity ◽  
Natural Conditions ◽  
Pollination Mechanism ◽  
Engelmann Spruce ◽  
Pollination Drop

The pollination mechanism of Picea engelmannii (Parry) was studied on small potted scions under natural conditions and in controlled environment chambers. Six stages of conelet development were recognized and related to pollen receptivity. Cone-lets appeared receptive for about 2 weeks but were actually receptive for only about 1 week. Secretory droplets appearing on the micropylar arms collected pollen for several days before pollination drops formed. Pollination drops formed acropetally in the conelet and only once from each ovule. Pollination caused rapid recession of the pollination drop, whereas the drop remained for several days on unpollinated ovules. There was some decrease in size of pollination drops during midday and reemergence the following night. Pollination drops were secreted by the nucellar tip in a manner similar to nectaries. Secretory cells collapsed following secretion. The drop contained 4.3% glucose and 3.8% fructose but no sucrose. High humidity increased the longevity and decreased the diurnal fluctuation in size of pollination drops. Conelets from trees with low leaf water potential developed more slowly and produced smaller and more viscous pollination drops. Cones averaged 103 ovuliferous scales, 90% of which were fertile. However, usually less than 50% of the potential seed set was achieved. One of the major causes for low seed set is inadequate pollination. A better understanding of the pollination mechanism and the receptive period may improve seed efficiency in controlled and supplemental mass pollinations.

The pollination mechanism in yellow cypress (Chamaecyparisnootkatensis)

1980 ◽  
Vol 10 (4) ◽  
pp. 564-572 ◽  
Author(s):  
John N. Owens ◽  
Sheila J. Simpson ◽  
Marje Molder
Keyword(s):  
Lipid Droplets ◽  
Pollen Grains ◽  
Water Droplets ◽  
Pollination Mechanism ◽  
Seed Cone ◽  
Pollination Drop ◽  
Micropylar Canal ◽  
The One ◽  
Cuticular Surface

Mature, dry, one-celled pollen was formed before pollen cones became dormant in the fall. Pollen averaged 27 μm in diameter, was irregular in shape, nonsaccate, and the surface was reticulate to tegillate-baculate and irregularly covered with orbicules. The pollen contained several large lipid droplets and no starch. No changes occurred in pollen during dormancy and pollen was shed at the one- or two-celled stage during the last half of March.All ovules were initiated and became flask shaped before seed-cone dormancy. No changes occurred in ovules during dormancy. Seed cones ended dormancy in early March, enlarged and opened, exposing the ovules. A pollination drop was produced by a breakdown of cells at the tip of the nucellus. A large pollination drop was exuded from each ovule in a cone but exudation did not occur at the same time in all ovules. Each ovule exuded and withdrew a pollination drop two to four times before the pollination drop was permanently withdrawn. Each ovule was receptive for a few days and each cone was receptive for about 1 week. The pollination drops were withdrawn in the presence or absence of pollen but were withdrawn more rapidly after pollen entered the pollination drop. The cuticular surface of the bract-scales prevented wetting of the surface and caused the beading of water droplets, which in turn could carry pollen to the micropyle. Pollen grains entering a pollination drop were withdrawn inside the drop into the micropyle. Cells lining the micropylar canal enlarged and sealed the canal while bract-scales enlarged and buried the ovules within the cone.

Nitrogen uptake and utilization by slow- and fast-growing families of interior spruce under contrasting fertility regimes

2003 ◽  
Vol 33 (6) ◽  
pp. 959-966 ◽  
Author(s):  
B D Miller ◽  
B J Hawkins
Keyword(s):  
Nitrogen Uptake ◽  
Picea Glauca ◽  
Dry Mass ◽  
Picea Engelmannii ◽  
Fertility Level ◽  
Fast Growing ◽  
Interior Spruce ◽  
Sib Families ◽  
Slow Growing ◽  
Mass Allocation

Six full-sib families of interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) of contrasting growth rates (three fast-growing, three slow-growing families) were grown from seed in a greenhouse under three fertility regimes (25, 75, and 125 mg nitrogen/seedling over 175 days). The use of vector analysis showed that the lowest fertility regime was nitrogen-limited while the highest indicated luxury consumption. After 175 days, fast-growing families were larger than slow-growing at all fertility levels. At the lowest fertility level, fast-growing families exhibited greater nitrogen productivity and utilization of internal nitrogen. At higher fertility levels, fast-growing families took up nitrogen more quickly and efficiently thus accumulating greater nitrogen reserves. Fast-growing families also exhibited a greater plasticity in dry mass allocation between shoots and roots with different fertility levels.

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