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Abstract
The Botanical Garden was conceived in 1968 when Dr. Fred C. Davison, President, charged a committee composed of faculty from the plant sciences “to study and present a final proposal for the establishment of a ‘Living Plant Library’ at the University of Georgia.” The epithet, Living Plant Library, was used in preference to botanical garden or arboretum which evoked memories of the original botanical garden at the University that existed from 1832 to about 1855; and/or the Arboretum started on South Campus about 1908 by Dr. T.H. McHatton, Head of Horticulture. Both gardens were extinguished by the path of progress – campus construction.
Abstract
Quality, the degree of excellence which a thing possesses, varies with the evaluator for excellence to one may be mediocrity to another. After considerable thought and examination of the literature, I have concluded that the quality attributes of woody ornamental plants as affected by mineral nutrition practices are not well defined. First, how exactly does one proceed to evaluate quality in a woody ornamental plant? The effects of mineral nutrition on the quality of vegetables and fruits would appear to be more obvious. Yield, color, firmness, taste, keeping quality, and chemical components may be useful traits for evaluating quality under a given set of nutritional, cultural, and environmental conditions In general quality on woody ornamentals appears to be related to visually pleasing, salable plants. There are various reports of fertilizer sources and rates on growth or appearance. I will review a limited number of these and then discuss the results of a questionnaire which was sent to nurserymen around the country concerning fertilization and woody ornamental plant production.
Abstract
Na2SO4, K2SO4, NaCl, KCl or CaCl2 at concentrations of 0.25N were applied daily as a soil drench or foliar spray to established plants of English ivy (Hedera helix L.). Marginal leaf necrosis developed after 28 days on plants drenched with Cl salts although necrosis was evident after 7 days and the injury was more severe on plants sprayed with Cl salts. Shoot dry weights of plants treated with Cl salts were significantly less than those of control or spray SO4 treatments. Leaf necrosis was not evident on plants drenched with SO4 salts, but shoot dry weights were significantly less than those of plants sprayed with SO4 salts or water. Shoot Na was greater from spray-applied Na salts compared to soil-treatments while shoot Cl was greater in soil-treated plants compared to spray Cl treatments. Shoot Cl generally corresponded with the severity of plant injury whereas shoot Na did not.
Abstract
Doublefile viburnums (Viburnum plicatum Miq. tomentosum Thunb.) were cultured at 2 pH ranges, 3 to 4 and 7 to 8, with 3 N treatments (NO3-N, NH4-N, or NO3-N plus NH4-N) supplied daily at a concentration of 1.5 meq N per pot. Fresh weights of shoots and roots from plants grown with NH4-N at pH 3 to 4 were significantly lower than from plants grown with other N treatments. Plants developed leaf necrosis and ultimately died when grown with NH4-N at pH 3 to 4. Limited leaf necrosis developed on other NH4-N treated plants. Leaf necrosis did not develop on leaves of plants grown with NO3-N at pH 3 to 4 or 7 to 8. Roots of all plants, except those grown with NH4-N at pH 3 to 4 appeared vigorous and healthy. Nitrate N was greatest in shoots of NO3-N treated plants. Shoot NH4-N levels were greatest in NH4-N treated plants and correlated with the severity of leaf necrosis. Total N concentration in shoots and roots were greatest in plants grown with NO3-N at pH 3 to 4 and NO3-N plus NH4-N at pH 3 to 4. In the growing medium, NO3-N predominated at the high pH range; NH4-N at the lower pH range. The N form and pH of the growing medium exerted marked effects on growth, and on N availability and utilization by viburnum.
Abstract
Salt tolerance of honeylocust (Gleditsia triacanthos inermis Willd.) was determined using 2 month-old potted seedlings salinized with 200 ml of NaCl, KCl and Na2SO4 at concentrations of 0.05N, 0.15N and 0.25N applied daily to soil. Leaflets of plants receiving Cl developed a tip and marginal necrosis while leaflets of plants receiving Na2SO4 were uninjured. Shoot dry weight of plants receiving NaCl and KCl (0.15N and 0.25N) were significantly lower than plants from control and all concentrations of Na2SO4 treatment Total soluble salts were not responsible for injury. Na had no adverse effect on growth although shoot Na levels were greater than 2% of dry weight in NaCl (0.15N and 0.25N) plants. Shoot Cl was a reliable index of the degree of salt injury, for the greater the tissue Cl, the more rapid the onset and the more severe the injury. Root Na and Cl levels were inconsistent and did not reflect the degree of injury observed. Honeylocust, although reportedly highly salt tolerant, was severely injured by exposure to Cl salts and this injury, correlated with shoot tissue analyses, suggested a specific ion effect.
Abstract
Cranberry plants, Vaccinium macrocarpon Ait. cv. Early Black, were grown with NO3-N, NH4-N or NO3-N + NH4-N at a concentration of 50 ppm N. Fresh weight of plants cultured on each Ν treatment was similar. Nitrate Ν was present in roots but not leaves. Ammonium Ν was present in both organs. Nitrate reductase activity was demonstrated in roots but not detected in leaves. Activity was significantly greater in roots of plants grown with NO3-N vs. NO3-N + NH4-N or NH4-N grown roots. Mycorr-hizae were not present in or on the roots and bacteria were eliminated as factors affected NO3 reduction. Results suggested cranberry was able to assimilate the NO3 form of N.
Cold hardiness levels of six cultivars of Chinese elm (Ulmus parvifolia Jacq.), `Select 380', `Orange Ribbon 740', `Emerald Isle', `Emerald Vase', `Drake', and `King's Choice', were determined over eight sample dates from 31 Aug. 1988 to 16 May 1989 and for `Emerald Vase' and `Drake', over three dates from 14 Feb. 1988 to 25 Apr. 1988. All cultivars tested achieved a maximum cold hardiness in December and January of – 21 to – 24C, except `King's Choice', which survived exposure to at least – 30C. `Emerald Isle' and `Emerald Vase' acclimated earlier (both – 9C on 31 Aug.) and reacclimated later (– 6 and – 9C, respectively, on 16 May) than other cultivars tested. `Emerald Vase' and `Drake' exhibited similar cold hardiness levels over the two years tested.
Buddleia species are attractive ornamental shrubs whose major cultural problem is infestations of the two-spotted spider mite. Two factors, drought stress and leaf pubescence, were examined for their effects on spider mite infestations. Drought stress was examined by placing 20 plants into a randomized block design and stressing ten of the plants. No differences in mite life parameters were found, although there was more uninfested area in nonstressed plants. This was probably due to the nonstressed plants' ability to outgrow the spider mite infestation. Leaf texture was examined by placing four female spider mites on 5 leaf disks of 37 cultivars and species of Buddleia and counting the number of eggs laid after 96 hours. There was a strong correlation between leaf pubescence and number of eggs laid. In a second experiment, using a shell vial with a leaf placed underneath the lid and five female spider mites in the vial itself, leaf pubescence was either removed with facial peel or left. In all cases but one, the removal of pubescence increased the number of eggs laid by the spider mites.
Stem cuttings from a prostrate clone of Cephalotaxus harringtonia (Forbes) K. Koch (Japanese plum yew) were taken monthly from Sept. 1994 through Aug. 1995, treated with K-IBA at 0 or 10,000 mg·liter–1, placed in a greenhouse under intermittent mist, and evaluated after 16 weeks. Cuttings taken from December to February and treated with K-IBA averaged 85% rooting, 10 roots per cutting, and a total root length of 35 cm. The next highest rooting percentages were for cuttings taken from March to May; poorest rooting occurred for cuttings taken from June to August and September to November, regardless of K-IBA application. Chemical name used: K-indole-3-butyric acid (K-IBA).
Plants of Salix alba `Britzensis' and Salix chaenomeloides were planted on 30, 60 or 90 cm centers in spring, 1992 and plants of Buddleia davidii `Black Knight' were planted at densities of approximately 45, 80, or 165 cm centers in fall, 1991. Stems of Buddleia were harvested in the summer and fall of 1992 and those of Salix were harvested in the winter of 1993. The number of stems/plant decreased but the number of stems/m2 increased with increasing plant density in all species. The stems of Salix alba `Britzensis' were significantly longer in the highest plant density.