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- Author or Editor: Stephen L. Buchmann x
Abstract
Airborne pollen concentrations (grains/m3) within and near trees of 2 cultivars of Olea europaea L. were studied during the 30-day pollination period at 2 urban sites in Tucson, Ariz. ‘Manzanillo’, the dominant horticultural cultivar, was compared to the fruitless ‘Swan Hill’. Air sampling using a Burkard trap was undertaken from 2 Apr. until 1 May 1985; during this period, 95% of the 1985 Olea pollen was airborne. Peak atmospheric Olea pollen concentrations at both sites occurred on 14 Apr. 1985. Pollen concentrations around the ‘Manzanillo’ site ranged from 7 grains/m3 to 6196 grains/m3 per day. At the ‘Swan Hill’ site, daily totals were an order of magnitude less, from 5 to 309 grains/m3 per day. Hourly pollen concentrations for the ‘Manzanillo’ site on the peak day varied from 1000 to 18,133 grains/m3 per hr. Hourly values at the ‘Swan Hill’ site on the peak day varied from 7 to 896 grains/m3 per hr. Both sites exhibited rapidly increasing pollen concentrations at sunrise with a sharp increase for the ‘Manzanillo’ site between 1100 to 1300 hr. Both cultivars produced about 85,000 pollen grains per anther. An unknown anatomical or physiological factor in ‘Swan Hill’ inhibits stomial rupture, resulting in 85% inhibition of anther dehiscence and pollen-shedding.
Abstract
Conditions for in vitro germination of jojoba [Simmondsia chinensis (Link) Schneider] pollen were optimized in order to study the influence of storage temperature on viability. A medium consisting of 300 mg·liter−1 CaCl2·2H2O, 100 mg·liter−1 KNO3, 10 mg·liter−1 H3BO3, 20% sucrose, and 4% to 5% Difco Bacto-agar was optimal for germinating both fresh and stored pollen. Pollen germinated readily in media with a pH range of 4 to 8. The optimum incubation temperature range for pollen germination was 25° to 30°C. When stored at room temperature (22° to 25°), the initial pollen viability was decreased to 50% in 3 weeks and to 0% after 10 weeks, as determined by in vitro germination. Pollen stored at 4° maintained its initial viability for 10 weeks, followed by a gradual decrease in germination to 70% in 17 weeks and 0% after 22 weeks. Pollen stored at −196° in liquid nitrogen for 2 years retained a germination percentage as high as that of fresh pollen. The eryogenieally stored pollen, when used in controlled pollinations, produced normal fruit set comparable to that with fresh pollen.