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  • Author or Editor: T. Davis Sydnor x
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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.

Open Access

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.

Open Access

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.

Open Access

Abstract

Columns of discolored and decayed wood associated with 42 wounds in silver maple (Acer saccharinum L.) were examined with a pulsed-current resistance meter (Shigometer) prior to dissection. Resistance measurements, expressed as a percentage of control readings, were correlated to depth, cross-sectional areas, and calculated volume of the discolored and decayed wood column. The instrument accurately detected the presence and depth of discolored wood. Relative decay volume could be established in a nondestructive manner.

Open Access

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.

Open Access

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.

Open Access

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°.

Open Access

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.

Open Access

Abstract

Five species of ornamental trees were examined with an Eppley pyranometer for interception of total solar radiation between 380 nm and 1100 nm. Measurements were made at the northern dripline and expressed as percentage of shade. Trees were selected for varying forms, branch, and canopy densities. Mean percentage of shade for the fully foliaged and leafless canopies, respectively, were Pyrus calleryana ‘Chanticleer’ 75% and 43%, Acer rubrum ‘Red Sunset’ 69% and 25%, Zelkova serrata ‘Village Green’ 61% and 24%, Gymnocladus dioicus 60% and 15%, Gleditsia triacanthos inermis ‘Moraine’ 56% and 21%. No statistically significant (PSO.05) correlation was observed among solar radiation intercepted and photosynthetically active radiation (PAR) intercepted, pathlength, silhouette area, and canopy volume. Growth habit did not affect shading capacities significantly.

Open Access

Abstract

Flower bud development was ascertained by biweekly dissections of shoot apices, until bud color was apparent. Satisfactory results were obtained when plants were given 3 weeks at 2 or 9°C, followed by 3 applications of GA3 at 250 ppm. The results were less satisfactory when attempts were made to completely substitute GA3 for the cool temp requirement to break dormancy.

Open Access