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- Author or Editor: Marlin N. Rogers x
Abstract
One of the prerequisites for a thriving profession of floriculture and ornamental horticulture is a continuing supply of enthusiastic and well-trained young people, who will eventually move into leadership and management positions. We need young people who have comprehensive bases in the fundamental sciences that underlie our profession, but who also have hands-on and practical backgrounds in the applications of this science to the art and sciences of horticulture. We need people who will eventually staff and manage our greenhouses and nurseries in production- and marketing-oriented positions. We also need scientists holding advanced degrees who will fill the teaching, research, and extension positions in our colleges, universities, and research institutes in the years to come.
Abstract
Since postharvest physiology of cut flowers was reviewed in some detail 10 years ago (109, 110), this review will concentrate primarily on more recent research, but will include such references to earlier work as are needed for clarification.
Abstract
Hardwood bark, amended with either urea (CO(NH2)2) or ammonium nitrate (NH4NO3) was composted in 210 liter drums at 10 to 40°C or heated to 55°. In the supplemental heat composted (SHC) bark amended with CO(NH2)2, pH increased to 6.8 to 7.4 within the first week. Bark amended with CO(NH2)2 generated more heat than bark amended with NH4NO3. Phenolic content decreased (as indicated by the Folin-Ciocalteu (F-C) method), and germination percentage of Lactuca sativa L. cv. Grand Rapids seed in water extracts of bark samples increased with time. Additions of polyvinylpyrrolidone (PVP) to extracts decreased phenolic content and increased the percentage of seed germination. Plant growth assays using Chrysanthemum × morifolium Ramat ‘Bright Golden Anne’ revealed a possible N deficiency in SHC NH4NO3 treated bark. Plants grown in SHC CO(NH2)2 amended bark did not have as severe a N deficiency. As time of composting increased, naturally composted (NC) bark treated with either N source gave plant growth comparable to that of the control plants grown in a medium of peat:perlite:vermiculite:soil (3:2:2:1 v/v).
Abstract
Concentrations of abscisic acid (ABA) in purified extracts of ‘#3 Indianapolis White’ were measured with a gas liquid chromatograph (GLC) and confirmed by combined gas chromatography-mass spectrometry (GC-MC). Apices contained 1½ to 3 times as much ABA as young or old leaves. Plants under long day (LD) treatment contained more ABA than those receiving short days (SD). ABA levels in the apices of plants sprayed with ethephon, (2-chloroethyl) phosphonic acid, and receiving 2 or 3 weeks SD, were lower than in plants given only 2 or 3 weeks SD.
Abstract
Sequential treatment of F1 hybrid geranium seedlings with different kinds and concentrations of chemical growth regulators produced well-proportioned plants with increased numbers of large-sized inflorescences and decreased flowering time compared with controls. (2-Chloroethyl)trimethylammonium chloride (chlormequat),α-cyclopropyl-α-(4-methoxzphenyl)-5-pyrimidine methanol (ancymidol) or (2-chloroethyl)phosphonic acid (ethephon) applied 2 to 3 weeks after potting caused increased production of branches and closely spaced initiation of several flower buds. These were hastened in growth and development by subsequent applications of gibberellic acid (GA3). Excessive increases in plant height caused by high-concentration GA3 applications were partly controlled by carefully timed second applications of either ancymidol or chlormequat.
Abstract
Chrysanthemum, ‘#3 Indianapolis White’, subjected continuously to atmospheres containing 1-4 ppm ethylene failed to initiate and develop flower buds under short day conditions. The plants showed typical epinastic symptoms, shortening of internodes, thickening of stems and loss of apical dominance. The plants developed many short axillary shoots, each with a few small leaves. The top leaves on the plant became smaller and smaller and were less dissected than the controls. Subjecting plants alternatively to ethylene containing and normal atmospheres generally prevented flowering also, but occasionally crown budding occurred. Bioassay of endogenous auxins showed that these growth promoting substances were maintained at high levels in the ethylene treated plants, which may account for their failure to flower. In addition, ethylene also seemed to affect the polar auxin transport system of the plant.