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Trees were grown for 2 years as a function of three container volumes (10, 27, and 57 liter) the first year and six shifting treatments (10 liter both years, 10 to 27 liter, 10 to 57 liter, 27 liter both years, 27 to 57 liter, or 57 liter both years) the second year when containers were spaced 120 cm on center, Height and caliper were greatest for magnolias grown in 27- or 57-liter containers both years. Caliper was greater for trees shifted from 10-liter containers to the larger container volumes compared to trees grown in 10-liter containers both years, Trees grown in 10-liter containers both years tended to have few roots growing in the outer 4 cm at the eastern, southern, and western exposures in the grow medium, During the second year, high air and growth medium temperatures may have been primary limiting factors to carbon assimilation during June and August. Using large container volumes to increase carbon assimilation and tree growth may be even more important when daily maximum air temperatures are lower during late spring or early fall compared to midsummer.
Premature flower bud abscission imposes a serious limitation on longevity of potted Hibiscus in interiorscape situations, Ethylene is known to be one causative factor. Past research has suggested that carbohydrate depletion of buds may also be involved,
A series of experiments was conducted to examine the relationship between carbohydrate levels and ethylene sensitivity of flower buds under low irradiance levels. Two cultivars were used: `Pink Versicolor', which is very susceptible to bud abscission, and the more resistant `Vista', In the first experiment, plants were harvested twice weekly after placement in interiorscape rooms (8.5 μmol m-2 s-1 for 12 hrs per day; 26.5°C day/night) until all buds had abscissed. At each harvest, buds from four size groups were collected for analysis. In the second experiment, source/sink strength of buds was manipulated by selective daily removal of certain sized buds. Remaining buds were collected just prior to abscission for analysis. In two additional experiments, `Pink Versicolor' plants were treated with either silver thiosulfate or ethephon prior to placement in interiorscape rooms. Plants were harvested twice weekly and buds collected. For all experiments, bud dry wt, total soluble sugars and starch content were determined.
Trees were grown for 2 years as a function of three container volumes (10, 27, and 57 liter) the first year and six shifting treatments (10 liter both years, 10 to 27 liter, 10 to 57 liter, 27 liter both years, 27 to 57 liter, or 57 liter both years) the second year when containers were spaced 120 cm on center, Height and caliper were greatest for magnolias grown in 27- or 57-liter containers both years. Caliper was greater for trees shifted from 10-liter containers to the larger container volumes compared to trees grown in 10-liter containers both years, Trees grown in 10-liter containers both years tended to have few roots growing in the outer 4 cm at the eastern, southern, and western exposures in the grow medium, During the second year, high air and growth medium temperatures may have been primary limiting factors to carbon assimilation during June and August. Using large container volumes to increase carbon assimilation and tree growth may be even more important when daily maximum air temperatures are lower during late spring or early fall compared to midsummer.
This study examined three transport systems used to transport fresh, non-stored cut flowers from Bogotá, Colombia, to the United States on a monthly basis for 1 year. Five cultivars of cut rose (Rosa hybrida), alstroemeria (Alstroemeria peruviana), carnation (Dianthus caryophyllus), and gerbera (Gerbera jamesonii) were commercially transported using a 7-day conventional distribution system with temperature controls and two rapid transport systems (3-day or 24-hour) with little or no temperature controls, respectively. Temperatures during the 24-hour transport system increased steadily and temperatures were at or above 10 °C for ≈18 h, with half of that time above 15 °C for all shipments. The 3- and 7-day systems had temperature fluctuations ranging from 3 to 24 °C and 3 to 19 °C, respectively. Flowers transported using the rapid transport systems had a significantly longer vase life compared with the 7-day transport in 83% of the shipments of alstroemeria and roses, in 58% of the shipments of carnations, and in 50% of the shipments of gerberas. Vase life increased 5.6% to 17.1% (0.7 to 2.1 days) for roses, 3.2% to 16.7% (0.5 to 2.7 days) for alstroemerias, 12.8% to 34.6% (1.1 to 6.2 days) for gerberas, and 4.6% to 8.8% (1.1 to 2.3 days) for carnations when using the rapid transport systems compared with the 7-day transport system. Some cultivars were more tolerant of the longer transport. The results show that when using fresh, non-stored flowers, the rapid transport systems had equal or longer vase life than the 7-day transport system in the majority of shipments for each flower species. Results also demonstrate that better temperature management during transport is a critical issue in the floral industry that needs to be improved upon.
Degraded inland and coastal water quality is a critical statewide concern in Florida and other states. Nutrients released from land-based human activities are present in water bodies resulting in algal blooms and increased eutrophication that impairs water bodies for their intended uses. There are differing approaches to addressing eutrophication, including voluntary adoption of current best management practices (BMPs) for nutrients, state regulation, or local county or municipal ordinances. The local ordinance, some including a summer (or so-called “wet season”) fertilizer ban or “blackout,” has been the chosen approach in some Florida counties and municipalities to address local water quality issues. Many components of these ordinances follow published BMPs, and there is agreement in the literature on the effectiveness of these practices for preventing nutrient losses from the landscape. However, there has been disagreement among stakeholders regarding the inclusion of a total fertilizer ban in a local ordinance. Regulators are asking about the best approach to controlling urban pollution and if banning fertilizer in the growing season would achieve the desired environmental protection and whether there are any potential unintended consequences associated with removing fertilizer from turfgrass growing in the summer months. The scientific literature documents the nature and scope of the water pollution problem, and numerous research reports have addressed fertilizer BMPs to prevent nutrient losses from the landscape. This article discusses the increased rate of eutrophication and reviews the pertinent national literature regarding managing urban landscape fertilization to protect water quality. Particular attention is given to fertilization practices during the active landscape plant (especially turfgrass) growth period that corresponds to the summer fertilizer bans in some Florida local ordinances. Therefore, special attention is paid to the question of what information is in the scientific literature and whether a fertilizer ban is the best way of achieving the goal of improving urban water quality. Research summarized in this review points to potential unintended consequences of increased nutrient losses from urban landscapes, particularly turfgrass, when proper, recommended fertilization and irrigation practices are not followed.
Abstract
• In the article “Efficacy of Ancymidol, Daminozide, Flurprimidol, Paclobutrazol, and XE-1019 when Followed by Irrigation”, by James E. Barrett, Carolyn A. Bartuska, and Terril A. Nell (HortScience 22(6): 1287–1289, December 1987), Table 1 was printed incorrectly. The corrected table appears below.
Exposure to 0.1, 1.0, or 10 μL·L−1 ethylene for 4 days at 21 °C reduced the display life of 17 commonly traded potted foliage plant genotypes (Aglaonema ‘Mary Ann’, Anthurium scherzerianum ‘Red Hot’ and ‘White Gemini’, Aphelandra squarrosa ‘Dania’, Chlorophytum comosum ‘Hawaiian’, Codiaeum variegatum pictum ‘Petra’, Dieffenbachia maculata ‘Carina’, Dracaena marginata ‘Bicolor’ and ‘Magenta’, Euphorbia milii ‘Gaia’, Euphorbia splendens ‘Short and Sweet’, Ficus benjamina, Polyscias fruticosa ‘Castor’, Radermachera sinica ‘China Doll’, Schefflera elegantissima ‘Gemini’, Schefflera arboricola ‘Gold Capella’, Spathiphyllum ‘Ty's Pride’). Ethylene treatment hastened leaf and bract abscission or senescence. The responsiveness of plants to ethylene varied considerably; six genotypes were sensitive to 0.1 μL·L−1 ethylene, whereas three genotypes required exposure to 10 μL·L−1 ethylene to trigger visible injury. Four genotypes (Asplenium nidus, Chamaedorea elegans ‘Neathe Bella’, Hedera helix ‘Chicago’, Syngonium podophyllum ‘White Butterfly’) included in our study were insensitive to ethylene. Treating Aglaonema ‘Mary Ann’, Polyscias fruticosa ‘Castor’, and Schefflera arboricola ‘Gold Capella’ plants with 0.9 μL·L−1 1-methylcyclopropene (1-MCP, provided as EthylBloc™), a gaseous ethylene-binding inhibitor, for 4 to 5 h at 21 °C reduced the deleterious effects of ethylene. The release of 1-MCP from two sachets containing EthylBloc™ into a single shipping box also protected Aphelandra squarrosa ‘Dania’, Euphorbia milii ‘Gaia’, Polyscias fruticosa ‘Elegans’, and Schefflera arboricola ‘Gold Capella’ plants from ethylene injury after simulated transport. Our data reveal the genetic variation in ethylene sensitivity among potted foliage plants and highlight genotypes that benefit from 1-MCP treatment.
Abstract
Vegetative Chrysanthemum morifolium Ramat. ‘Nob Hill’ plants were treated with foliar sprays of ancymidol, daminozide, flurprimidol, paclobutrazol, or XE-1019 and then overhead-irrigated 0.5, 1, 2, 4, 8, or 24 hr later. Irrigation prior to 4 hr reduced the efficacy of daminozide but did not alter efficacy of other chemicals. Efficacy was not affected when similar plants were treated with a medium drench of the same chemicals, except daminozide, and followed with irrigation at 1,24, or 48 hr. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrmidinemethanol (ancymidol), butanedioic acid mono-(2,2-diemthylhydrazide) (daminozide), α-(l-methylethyl)-α-[4-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol (EL-500) (flurprimidol), (±)-(R*,R*)-beta-((4-chlorophenyl)methyl)-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (PP-333) (paclobutrazol), and (E)-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-l-penten-ol (XE-1019).
A series of experiments on ethylene-insensitive (EI) petunia plants (Petunia ×hybrida Hort. Vilm.-Andr.) generated in two genetic backgrounds were conducted to determine the involvement of ethylene in horticultural performance. Experiments examined various aspects of horticultural performance: days to flower, flower senescence after pollination and without pollination, fruit set and ripening, and adventitious root formation on vegetative stem cuttings. The development of EI plants was altered in several ways. Time from seed sowing to first flower anthesis was decreased by a week for EI plants grown at 26/21 °C. Flower senescence in nonpollinated and self-pollinated flowers was delayed in all EI plants compared to wild-type plants. Fruit set percentage on EI plants was slightly lower than on wild-type plants and fruit ripening on EI plants was delayed by up to 7 days. EI plants produced fewer commercially acceptable rooted cuttings than wild-type plants. There was a basic difference in the horticultural performance of the two EI lines examined due to a difference in the genetic backgrounds used to generate the lines. EI plants displayed better horticultural performance when grown with day/night temperatures of 26/21 °C than 30/24 °C. These results suggest that tissue-specific ethylene insensitivity as well as careful consideration of the genetic background used in transformation procedures and growth conditions of etr1-1 plants will be required to produce commercially viable transgenic floriculture crops. EI petunias provide an ideal model system for studying the role of ethylene in regulating various aspects of plant reproduction.