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- Author or Editor: Patricia S. Holloway x
Abstract
Seeds of Alaska iris, Iris setosa Pall. ssp. interior (Anders.) Hult., were collected from wild stands near Fairbanks and subjected to the following treatments: 0 or 125 days of stratification; 24-hr soak in water or 1000 mg·liter-1 gibberellic acid (GA3); alternating (25°/10°C) or constant (21°) temperatures; and germination in darkness or light. After 7 days, germination was best (95.0%) with stratified seeds that were soaked in GA3 and germinated at constant temperatures in the dark. A greenhouse study in which stratified seeds were soaked in water or GA3, sown in a commercial peat and vermiculite seed germination mix, and germinated beneath clear or black plastic confirm ed that germination was highest (64.4%) and most uniform (83.3% filled container cells) with the com bined treatments of GA3 and darkness.
Five woody ornamentals Rosa rugosa, Cotoneaster acutifolia, Malus baccata, Picea glauca and Pinus contorta var. latifolia, were grown for 4 seasons mulched with one of five treatments: 2.5 cm or 5 cm of crushed basaltic quarry stone, 5 cm or 10 cm of quaking aspen wood chips, and an unmulched control. Maximum soil temperatures at the 10 cm depth on the wood chip plots were decreased by as much as 8°C over control plots, and soil moisture was increased. Stone mulch plots showed a slight increase in both temperature and moisture. Soil minimum temperatures were lower on the wood chip plots than the other treatments early in the season, but were slightly higher in September. Soil pH and available N, P and K did not differ among mulch treatments. Weed growth was suppressed by all mulch treatments but was best controlled on the wood chip plots followed by the 5 cm stone plots. Plant growth for all species except Rosa rugosa was greatest on the stone mulch plots. Roses growing on the stone mulch plots and the control were subject to significant dieback from winter injury and did not show any difference in total growth after 4 years when compared with the wood chip plots. Plants grown on the wood chip plots exhibited varying degrees of nitrogen deficiency which may be related to reduced nutrient uptake in cooler soils or to a significant amount of rooting in the mulch-soil interface.
Five woody ornamentals Rosa rugosa, Cotoneaster acutifolia, Malus baccata, Picea glauca and Pinus contorta var. latifolia, were grown for 4 seasons mulched with one of five treatments: 2.5 cm or 5 cm of crushed basaltic quarry stone, 5 cm or 10 cm of quaking aspen wood chips, and an unmulched control. Maximum soil temperatures at the 10 cm depth on the wood chip plots were decreased by as much as 8°C over control plots, and soil moisture was increased. Stone mulch plots showed a slight increase in both temperature and moisture. Soil minimum temperatures were lower on the wood chip plots than the other treatments early in the season, but were slightly higher in September. Soil pH and available N, P and K did not differ among mulch treatments. Weed growth was suppressed by all mulch treatments but was best controlled on the wood chip plots followed by the 5 cm stone plots. Plant growth for all species except Rosa rugosa was greatest on the stone mulch plots. Roses growing on the stone mulch plots and the control were subject to significant dieback from winter injury and did not show any difference in total growth after 4 years when compared with the wood chip plots. Plants grown on the wood chip plots exhibited varying degrees of nitrogen deficiency which may be related to reduced nutrient uptake in cooler soils or to a significant amount of rooting in the mulch-soil interface.
Research was initiated in 1990 to study spore viability, spore germination in vitro, and methods of controlled environment culture for the endangered Aleutian shield-fern, Polystichum aleuticum. Examination of spores using scanning electron microscopy revealed from 24% to 78% deformed and possibly nonviable spores per plant. Normal spores germinated in 30-45 days on both Knop's solution and Hoagland's No 2 solution in aseptic culture. Germination was most rapid on cultures with less than 6 g/1 agar. Cultures with no agar were susceptible to contamination by algae, and sporophyte losses during transfer to greenhouse media were high. Germination rate and subsequent appearance of the first leaf stage did not differ significandy within a medium pH range of 4.7 to 7.0. Spores exhibited a thermodormancy at 25°C, but germinated well at 18°C and required light for germination. Sporophyte transfer from aseptic culture was most successful after true fronds beyond the first leaf stage had developed. A commercial bedding plant mix composed of Sphagnum sp. peat and perlite provided an optimum rooting medium for the ferns.
Frozen lingonberries (Vaccinium vitis-idaea subsp. minus) and bog blueberries (V. uliginosum) were processed using recipes of the Alaska Cooperative Extension Service. Overall antioxidant activity (H-ORAC) was 71 μmol·g-1 of TE for frozen bog blueberries and for lingonberries, 160–165 μmol·g-1 of TE. Processing into fruit leather and drying increased levels in bog blueberries to 260–430 μmol·g-1 of TE and lingonberries to 457–939 μmol·g-1 of TE. Leathers and dried fruit had significantly higher levels of total anthocyanins (frozen bog blueberries: 2.1 μg·g-1, leather: 8.0 μg·g-1, dried: 9.8 μg·g-1; frozen lingonberries 1.4 μg·g-1, leather: 4 μg·g-1, dried: 5.2 μg·g-1); total phenolics (frozen bog blueberries: 4.8 μg·g-1, leather: 19 μg·g-1, dried: 26 μg·g-1; frozen lingonberries 7.7 μg·g-1, leather 24 μg·g-1, dried: 38 μg·g-1); and quercetin (frozen bog blueberries: 6.7 μg·g-1, leather: 86 μg·g-1, dried: 150 μg·g-1; frozen lingonberries 7.7 μg·g-1, leather 110 μg·g-1, dried: 430 μg·g-1). Bog blueberries did not have detectible levels of p-coumeric acid or benzoic acid, but lingonberries showed a significant increase in dried fruit and leather (frozen fruit p-coumeric: 0.18 μg·g-1g, leather: 0.45 μg·g-1, dried: 1.4 μg·g-1; frozen fruit benzoic: 0.41 μg·g-1, leather: 0.84 μg·g-1, dried: 0.71 μg·g-1). Frozen and processed lingonberries had little or no vitamin C. Bog blueberries had detectible levels in all treatments [highest in leather (440 μg·g-1), frozen berries (220 μg·g-1)]. ORAC, total anthocyanins, total phenolics, and quercetin were detected in all other processing methods (canned fruit, syrup, canned juice, jam, sauce, frozen j uice, and freezer jam). Levels were similar to or lower than frozen fruit.
Seeds of three Sanguisorba species native to Alaska were germinated in growth chambers with constant air temperatures of 5°, 10°, 15°, 20°, 25°, or 30°C and an irradiance of 150 μM·m–1·s–2 for an 18-hr photoperiod to identify optimum germination in relation to temperature and light. Four replicates of 100 seeds each were sown onto filter paper in petri dishes in each temperature treatment. At 20°C, four additional dishes per species were enclosed in foil to exclude light. Dishes were arranged at random by species in large clear plastic bags, and daily counts of radicle emergence were recorded. Germination of all three species was fitted to third-order polynomial equations by regression analysis. The predicted optimum germination temperature for Sanguisorba officinalis was 25°C; S. menziesii was 24°C; and S. stipulata was 25°C. Germination was most rapid (days to 50% germination) for each species in the 25°C treatment. S. stipulata did not germinate at 5°C, and both S. stipulata and S. menziesii showed less than 50% germination at 30°C. Seeds of all species germinated as well in darkness as in light.
Yields of `Quinault' everbearing strawberries were compared during three seasons for plants grown under eight different mulch treatments with or without polyethylene row covers. In 1987, yields using clear polyethylene mulch with or without row covers (3.81 kg/m2 and 3.45 kg/m2, respectively) were significantly greater than all other mulch, treatments. Yields ranged from 1.05 kg/m2 to 2.60 kg/m2 for black polyethylene; black over white two-sided, embossed polyethylene; black latex liquid; permeable landscape fabric; white over black two-sided, embossed polyethylene mulch, all with row covers or the unmulched control plot without a row cover. During the second year, yields using clear polyethylene mulch were significantly greater than all treatments except for black polyethylene (5.32 kg/m2 and 4.74 kg/m2, respectively). Yields for the other mulch treatments ranged from 3.55 kg/m2 to 3.85 kg/m2. The summer of 1988 was warmer than average which may account for the improved performance of the black polyethylene mulch. In 1989 results were similar to 1987 in which the clear polyethylene mulch had significantly higher yields (5.66 kg/m2) than all other mulches (2.12 - 4.31 kg/m2). Clear polyethylene mulch with or without row covers is recommended for everbearing strawberry production in Alaska,
Berries and vegetables can be sources of beneficial phytochemicals that may have antioxidant activity in the human diet. Information on type and quantity of phytochemicals may open new crop opportunities for berries and vegetables harvested in Alaska. A method was developed for detecting ascorbic acid and eight phenolic acids on an HPLC instrument using a reverse phase Merck Chromolith C18 column. The method used UV absorbance detection at 280nm to separate a standard solution of the following nine phytochemicals: ascorbic acid, gallic acid, protocatechuic acid, p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, caffeic acid, syringic acid, p-coumaric acid and ferulic acid. The mobile phase was a mixture (3.5% to 14% gradient) of organic solvent (5 parts acetonitrile: 2 parts methanol) and aqueous solvent (2 mmol aqueous trifluoroacetic acid - TFA) at a flow rate of 2 mL/min. In 2003, over 60 samples of berries and 60 samples of baby greens were extracted and analyzed. Plant samples were extracted by blending 10-20g of frozen plant tissue with 5 parts TFA. The extracts were centrifuged, diluted 4:1 and filtered (0.2 μm). Chromatograms from HPLC analysis for all samples were complex in peak size and number. Chromatograms for six extracts of high bush cranberries, Viburnum edule, exhibited intense peaks that indicate the presence of caffeic acid, based on retention times. Chromatograms for seven extracts of rose hips, Rosa acicularis, exhibited peaks that indicate the presence of ascorbic acid, based on retention times. Gallic acid and p-hydroxybenzoic acid are apparent minor components in the leaves of some baby greens. This research will continue in 2004 with more plant samples and further method development for detection of other phytochemicals.
Abstract
A single application of 50, 100 or 500 mg/liter gibberellic acid (GA) during 75% full bloom induced seedless fruit development in lingonberries growing in their native habitat in Alaska. Fruit set was increased by the 500 ppm GA treatment in the absence of insect pollination. Fruit set was not increased by GA in open-pollinated plants. Berry weight and diameter were unaffected by GA treatments.
Abstract
Three seedling populations of lingonberries from Fairbanks, Alaska, Oulu, Finland, and the Pasvik River Valley, Norway were exposed to 0, 170, 344, 513, 681, 843, 1013, and 1185 hours of continuous chilling temperatures (4 ± 1°C) to determine chilling requirements necessary to satisfy rest. Both the Finnish and Alaskan populations required at least 681 hours of chilling to obtain maximum terminal vegetative budbreak. Continuous chilling for 1185 hours was insufficient to obtain maximum budbreak in the Norwegian population. In the Finnish and Alaskan populations neither the percentage of stems exhibiting lateral budbreak nor the number of lateral branches per stem differed among chilling treatments. Plants from Norway showed significantly greater lateral budbreak in the 513- and 681-hour treatments than in all other treatments. At least 681 hours of chilling were necessary to achieve normal flowering in the Finnish population.