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- Author or Editor: T. Davis Sydnor x
Abstract
The 1980s are predicted to be a decade of change for the academic community. The 1960s were characterized by rapid increases in student numbers in all areas of higher education. Because of the tremendous demand, universities were able to hire additional faculty and staff. The 1970s were characterized by a relatively static enrollment period in most areas of the U.S. Numbers of new positions decreased, while student numbers and demand for services remained reasonably constant. Horticulture’s history during this period was slightly different. While student numbers increased during the 1960s, on a percentage basis, absolute numbers remained reasonably constant. Growth in horticulture came during the 1970s, when the number of new faculty positions being created were lower. The result has been strained budgets and nerves, as horticulture departments have been forced to provide services for a large number of students without the rapidly increasing budgets characteristic of the 1960s.
Abstract
Phytotoxicity of burlap treated with 6 concentrations of CuSO4 or copper naphthenate (Cu Nap) was determined by enclosing the root balls of Cotoneaster divaricata in the treated burlaps, observing their growth for 40 weeks, and analyzing root, stem and leaf tissue for Cu, Fe, and Mn. Burlap treated with up to 4.0% Cu Nap or levels of CuSO4 less than 0.2% was not phytotoxic. Burlap treated with solutions of CuSO4 ≥0.2% was phytotoxic. Tissue analyses indicate that the injury from CuSO4 treated burlap was the result of high Cu concentrations in the roots of enclosed plants.
Abstract
Treatment of burlap with copper sulfate (CuSO4) or copper naphthenate (Cu Nap) retarded its deterioration in soil. Deterioration of CuSC4-treated burlap was independent of treatment concentration while deterioration of Cu Nap-treated burlap was directly related to treatment concentration. Burlap treated with CuSC4 had a higher Cu content and lower initial break strength than burlap treated with Cu Nap. At 24°C, burlap treated with CuSC4 retained effective strength an average of 27 weeks, with Cu Nap, between 8 and 72 weeks. The rate of deterioration was significantly lower at 2°.
Abstract
Three gibberellins; GA3, GA4, GA7; and abscisic acid (ABA) from the shoot tips of greenhouse grown ‘Gloria’ azaleas, Rhododendron sp.L., were tentatively identified using column chromatography, gas-liquid chromatography, and Rumex leaf senesence bioassay. Growth regulators were quantitatively estimated biweekly from 6 weeks after shoot tip removal until anthesis.
GA3 levels remained nominal for the normal commercial treatment until after plants were returned to 19°C from the 9° cooler. Endogenous GA3 levels then peaked at 0.6 μg/bud at anthesis. GA4 levels remained fairly constant for all treatments and times at 0.1 μg/bud. GA7 levels remained fairly constant below 2 μg/bud except in the cold-treated plants when endogenous GA7 levels peaked at 0.6 μg/bud at the time that plants were removed from the cooler.
ABA levels were similar until 24 wks. from pinch when the levels dropped to undetectable levels in cold-treated plants and increased in treatments not given a cold treatment by peaking at 0.1 μg/bud at 28 wks. from pinch.
Of the commercially available gibberellins that were monitored, GA7 seemed to be the best treatment for chemically overcoming flower bud dormancy in azalea.
Abstract
Euonymus (Euonymus fortunei colorata Rehd.), English ivy (Hedera helix L.), and pachysandra (Pachysandra terminalis Sub. & Zucc.), were evaluated for their capability to produce a mat of ground cover plants in sod-like configuration. Euonymus and English ivy produced a satisfactory product in 12 weeks while pachysandra required 16 weeks. Of 7 media evaluated with English ivy as the test plant, pine bark mulch, peatmoss-perlite, and Metro Mix 300 were judged superior in transportability, overall quality and landscape acceptance to peatmoss-Haydite-perlite, peatmoss-Haydite, peatmoss-sand, and hardwood bark. Euonymus and English ivy sods in pine bark mulch and peatmoss-perlite media were evaluated for landscape establishment. Both species rooted into the soil and established without appreciable loss 6 months after transplanting into the field.
Abstract
Purposefully inflicted wounds were observed on 12 species of trees commonly used in urban landscapes and along city streets. One group was observed in an urban environment in Nashville, Tenn., the other in a rural lawn environment in Wooster, Ohio. Wound closure in both environments was more closely correlated to species than to commonly used growth parameters. In both environments, Fraxinus pennsylvanica and Liquidambar styraciflua closed wounds more quickly than Pyrus calleryana ‘Bradford’, Gleditsia triacanthos var. inermis, and Betula nigra.
Abstract
Low light intensity caused an increase in size and a delay in flowering of gloxinias (Sinningia speciosa Benth and Hooke cv. Dwarf Delight and Royal Frosted Red). The growth regulators succinic acid-2,2-dimethyl hydrazine (SADH) and (αcyclopropyl-α-(4 methoxyphenyl)-5-prymidinemethanol (ancymidol) decreased plant size and delayed flowering. ‘Dwarf Delight’ showed damage in response to ancymidol at 250 mg/liter and higher but ‘Royal Frosted Red’ showed no damage. SADH caused a noticeable increase in anthocyanin content of the inflorescence and chlorophyll content of the leaves.
Abstract
Photographs of five fully foliaged shade tree canopies (Acer. rubrum, Gleditsia triacanthos inermis, Gymnocladus dioicus, Pyrus calleryana, and Zelkova serrata) were taken using four film types, 50- and 28-mm lenses, and a range of three f-stops. Photographs of four leafless shade tree canopies (Gleditsia, Gymnocladus, Pyrus, and Zelkova) were taken using three film types and two lenses, at two f-stops. Film densities were determined with a light source and quantum sensor system for negatives of fully foliaged and leafless canopies and correlated with mean percentage of shade measured with a pyranometer. Pan-X film, at the correct f-stop setting, gave the highest correlation to mean percentage of the fully foliaged canopies. The 50-mm lens gave a higher correlation than the 28-mm lenses. Plus-X film, at an f-stop one above the proper setting, gave the highest correlation to mean percentage of shade of the leafless canopy. Plus-X film produced the most consistent results when photographs of the leafless canopy were taken during different days and times of the day. Using a densitometer to measure film density of the negatives gave high correlations to mean percentage of shade of the leafless canopy.
Abstract
The influence of leaching and water quality on the service life of Cu-treated burlap was investigated. Copper ammonium carbonate (CAC) and copper naphthenate (Cu Nap) treated burlap were more resistant to leaching with distilled H2O than CuSO4-treated burlap. When evaluating water quality, burlap treated with CuSO4 was found to be susceptible to ionic exchange of the Cu by Fe, Ca, Mg, Na or K. Soil burial tests of burlap treated with Cl or SO4 salts of Cu, Fe, Ca, Mg, Na and K resulted in the replacement of Cu and burlap deterioated within 1 month which was similar to untreated burlap. Water quality of leachates from 12 organic holding media such as pine bark, contained Ca and Mg in concentrations high enough to replace Cu in CuSO4-treated burlap. An inert holding media such as river sand would be preferred to reduce ion replacement and thus extend the service life of Cu-treated burlap.
Abstract
Wound closure and growth data were determined over a 2-year period for 12 cultivars of red maple (Acer rubrum L.) and branch and trunk wounds were analyzed for extent of associated discolored wood. A cultivar effect was noted in both closure and compartmentalization rates. ‘Armstrong’, ‘Doric’, ‘Gerling’, and ‘October Glory’ exhibited below average closure rates; ‘Schlesinger’, ‘Autumn Flame’, and ‘Autumn Glory’ had a more rapid closure rate in response to wounding. ‘Red Sunset’ and ‘Schlesinger’ were above average and ‘Bowhall’ and ‘Scanlon’ were below average in capacity to compartmentalize wounds. Previous years' twig extension growth was a good prediction of a plant's ability to close wounds. Higher nutrient levels of callus were associated with higher closure rates.