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  • Author or Editor: John D. Martin x
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Abstract

Several film forming antitranspirants were applied to salable, flowering chrysanthemum plants prior to placement in a controlled environment devised to simulate the interior of a home. Significant reductions in water loss resulted with all applications, with over a 40% reduction at highest concentrations. No discernable increase in floral display life was observed with any treatment. Higher concentrations of chemicals caused yellowing of foliage, and in some cases imparted a sticky residue or in some way impeded normal floral expansion. Film effectiveness persisted for at least 2 weeks with consistantly high transpiration losses for non-treated plants.

Open Access

Abstract

Three film-forming antitranspirants were applied to potted chrysanthemums (Chrysanthemum morifolium Ramat.) under greenhouse conditions from the time of potting rooted cuttings to saleable size. Folicote (a hydrocarbon wax emulsion of essentially fully refined paraffin) reduced water loss by an average of 39% and by as much as 65%, but generally detracted from plant appearance, delayed flowering, depressed fresh and dry weight, decreased flower size, increased height and reduced leaf area. While Clear Spray (a lateral based emulsion of undefined composition) and Wilt Pruf NCF (whose active ingredient is a polyterpene compound, Pinolene) reduced water loss 8 and 11% respectively, their side effects were less deleterious and, in a few cases, beneficial. Effects of antitranspirants under summer greenhouse conditions appeared to be of a greater magnitude than during a cooler season of the year.

Open Access

Abstract

The muskmelon cultivar Honey Dew (Cucumis melo L.) has unique horticultural and physiological characteristics, most notably an unusually long period between attainment of acceptable horticultural maturity and self-ripening in the field. Patterns of flowering, fruit set, fruit growth, solids accumulation, softening, ethylene production, respiration, and variation among individual fruits were studied during several seasons. Internal ethylene concentration may be estimated by the following formula: ppm internal = 3.7 ± 1.2 × rate of production in µl/kg-hr. The act of harvesting had no effect on ethylene production or internal concentration. Full ripening required an internal ethylene concentration of about 3 ppm. Horticultural maturity was attained at 35 to 37 days after anthesis, but self-ripening required about 47 days. Commercial harvests include fruits in this range of ages, so treatment with ethylene is required for uniform ripening and consumer satisfaction.

Open Access

A long-term horticultural experiment was conducted at two geographically distinct sites in southern Missouri in 2011–15 to study the response of American elderberry [Sambucus nigra (L.) subsp. canadensis (L.) Bolli] to various soil nitrogen (N) fertilizer levels. Three commercially available elderberry cultivars (‘Adams II’, ‘Bob Gordon’, and ‘Wyldewood’) were used. The three cultivars were each assigned to 16 of 48 four-plant plots in a completely randomized manner at each site. Four replications of four N fertilizer treatments (0, 56, 112, 169 kg⋅ha−1 N) were randomly assigned to each cultivar’s plots and applied for 4 years (2012–15). Fruit yields, plant growth, phenology, and pest incidence were determined each year. Fruit quality was assessed by analyzing basic juice characteristics as well as organic acids, carbohydrates, anthocyanins, and polyphenols from 2012–14 samples. Leaf tissue analysis determined the plants’ mineral contents in 2012–14. Most factors evaluated were significantly affected by site, year, and cultivar, whereas the effects of N fertilizer treatment were less definitive. Fruit yields and plant growth increased with increasing N levels. For example, plants fertilized with 0, 56, 112, and 169 kg⋅ha−1 N produced 123, 137, 155, and 161 fruiting cymes per plot (5.8 m2), respectively. The eriophyid mite incidence was higher on fertilized plants, but other pests were not influenced by the N treatment. Basic fruit juice characteristics (soluble solids, pH, titratable acidity, polyphenols) were not influenced by the N treatment, whereas total anthocyanins were statistically higher in unfertilized plants. Levels of organic acids and carbohydrates in juice varied statistically among N treatments, but patterns were difficult to discern. Leaf N concentrations were correlated with N fertilizer levels—2.75% N with the highest fertilizer level compared with 2.55% N in unfertilized plants. Leaf levels of most other macronutrients varied, but consistent patterns did not emerge, and none of the micronutrients was different among N treatments. Although elderberry plants responded positively to increased N fertilizer levels in terms of plant growth and fruit yield, genetics (cultivar) and environment (site, year) were more influential on most other experimental factors evaluated.

Open Access