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Abstract

Storage at 4.5°C prevented decay of cut fronds of leatherleaf fern [Rumohra adiantiformis (G. Forst) Ching] artificially inoculated with Cylindrocladium heptaseptatum Sobers, Alfieri, & Knauss and/or naturally infected with C. pteridis Wolf and increased frond vase-life compared to 24° storage. Storage at 4.5° for 10, 21, and 31 days did not affect subsequent frond vase-life. Inoculation of fronds decreased vase life by 11% in one experiment and had no effect in a second. Prestorage dips in benomyl suspensions at concentrations as low as 38 ppm reduced frond decay by 82% when stored at 24° and increased vase-life of fern stored at both 4.5° and 24°. Benomyl [methyl l-(butylcarbamoyl)-2-benzimidazole-carbamate] dips at concentrations as high as 300 ppm had no detrimental effect on vase-life. Iprodione [3-(3,5-dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide] had no effect on vase-life.

Open Access

A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for Dieffenbachia maculata [(Lodd.) G. Don] `Camille' greenhouse production. Three soilless foliage plant growing mixes [Cornell, Hybrid, Univ. of Florida #2 (UF-2)] were prepared using either SP or CD and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (percent by volume): Cornell = 50 CD or SP:25 V:25 P, Hybrid = 40 CD or SP:30 V:30 PB, UF-2 = 50 CD or SP:50 PB. Initial CI concentrations and electrical conductivities were higher for CD-containing media (CDM) than SP-containing media (SPM). At termination, Ca, Mg, and NO3-N concentrations were higher for SPM than CDM. Bulk densities were lower for CDM than SPM for one medium, but not for the others. Water-filled pore space (W-FPS) and water-holding capacity (W-HC) were larger and air-filled pore space (A-FPS) generally was smaller for CDM than SPM. Cornell had the highest W-FPS and W-HC, lowest A-FPS and percentage of large particles, and produced the highest grade and heaviest plants. Plant top grades, fresh mass and overall mass, but not root grades and mass, were higher for CDM than SPM. Plant mass was positively correlated with initial medium W-HC but not with A-FPS. Lower K in mix UF-2 compared to the mixes containing vermiculite may have been partly responsible for the lesser growth in that mix.

Free access

A comparison was made of Philippine coconut coir dust and Canadian spaghnum peat as components of three growing media for greenhouse production of Dieffenbachia maculata `Camille'. The soilless media were prepared using coir or peat in various amounts (by volume) combined with pine bark, vermiculite, and/or perlite (Media A–50% coir/peat: 25% vermiculite: 25% perlite; Media B–40% coir/peat: 30% vermiculite: 30% bark; Media C–50% coir/peat: 50% bark). Chemical and physical properties of the soils were determined at the beginning and the end of the five-month production cycle. Plant root and top growth and grades were determined at the end of the experiment. Initially, saturated media extracts from coir-containing media had elevated K, Cl, and soluble salts levels compared to peat-containing media; however, by the end of the experiment those levels were lower in coir- than in peat-based media. Water-filled pore space and water-holding capacities were generally higher and air-filled pore space lower in coir- than in peat-based media, probably due to differences in particle size distributions. There were no interaction effects on plant growth between growing media and coir versus peat. Plant root and top growth in Media A > Media B > Media C and plant top growth was greater in coir- than in peat-based media. Differences in growth could be due, in part, to differences in media water-holding capacities.

Free access
Authors: and

Abstract

Four herbicides, alone and/or in combination, were evaluated for weed control in beds of leatherleaf fern [Rumohra adiantiformis (G. Forst) Ching]. Fair winter weed, predominantly chick weed [Stellaria media (L.) Cyr.], control was obtained with simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] at 2 kg active ingredient (a.i.)/ha, simazine + metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 1.1 + 2.2 kg a.i./ha and oxadiazon [2-terf-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] + simazine at 1.1 + 1.1 kg a.i./ha. Oxadiazon + simazine, oxadiazon + metolachlor at 1.1 + 2.2 kg a.i./ha, and simazine + metolachlor controlled spring weeds. All herbicide treatments gave fair weed control in summer. Except for simazine applied alone, none of the treatments injured leatherleaf fern visibly. Oxadiazon + metolachlor, oxadiazon + simazine, and simazine + metolachlor reduced winter weeding times. All combination treatments reduced spring weeding times, but none of the treatments reduced summer weeding times. No treatment reduced fern yield or affected average frond weights. Frond length and frond weight were positively correlated (r = 0.74).

Open Access

Abstract

Episcia cupreata (Hook.) Hanst. ‘Pink Panther’ plants were drenched with 0, 0.07, or 0.21 mg a.i. paclobutrazol and given night interruption lighting (NIL) of 4 hr (2200-0200 hr) at 2.6 μmol·s−1·m−2 or no light interruption. Paclobutrazol and NIL did not affect days to first flowering, while flower numbers per plant increased exponentially over time on paclobutrazol-treated and control plants. NIL increased flowers per plant from day 47 on. Flower longevity was greater on paclobutrazol-treated plants than controls. Plant size (canopy radius) was reduced by paclobutrazol, which caused a greater flower density per canopy area. Chemical name used: (R*, R*)-(±) β-[(4-chlorophenyl)methyl]-α-(l,l-dimethylethyl)-1H-l,2,4-triazole-1-ethanol (paclobutrazol).

Open Access

Zygotic embryo explants of grape cultivar AXR#1 were isolated from maw-e seeds and cultured on medium supplemented with naphthoxy acetic acid beta-(NOA) and benzylaminopurine (BA). Embryo explants dedifferentiated to form embryogenic callus. Globular stage embryos were visible in 9-10 months. On transfer 10 a growth regulator free medium supplemented with charcoal these globular embryos underwent further stages of embryo development. In a period of 30-40 days embryogenic tissues turned into clumps of somatic embryos displaying different stages of development Cotyledonary stage embryos were separated and transferred to basal medium. These embryos developed into complete plants. Cold and desiccation treatment of somatic embryos significantly enhanced the rate of plant conversion. Hypocotyl segments of elongated somatic embryos were good source explant for induction of shoot organogenesis. The hypocotyl-length and the proximity to-shoot-apex were found to influence the rate of shoot induction from hypotyl segments. Multiple shoot complexes which formed on hypocotyl segments were separated and individual shoots were grown on a root induction medium resulting in complete plant development. The possibility of both embryogenic and organogenic modes of plant regeneration make somatic embryos a highly versatile explant source for experiments on genetic manipulation.

Free access

Abstract

Leatherleaf fern [Rumohra adiantiformis (Forst.) Ching] was grown in controlled environment chambers set for day/night temperatures of 35/24C (high temperature regime, HTR) or 24/13C (low temperature regime, LTR). Fronds were harvested for vase life studies at 1100 and 1800 HR and held in holding rooms in deionized water. Plants were then moved to a greenhouse environment (16–25C) and, after 1 week, an additional set of fronds were harvested. Water uptake of harvested fronds declined exponentially and was generally lower for HTR fronds. HTR fronds had, for the most part, reduced vase life compared to LTR fronds. Most (81%) of the HTR fronds exhibited desiccation symptoms, whereas none of the LTR fronds did. These differences did not appear to be related to preharvest diffusive resistance or water potential differences.

Open Access

Abstract

Twenty gerbera (Gerbera jamesonii H. Bolus, ex Hook f.) cultivars were evaluated for longevity in deionized water (DI), deionized water containing 1 mg fluoride (F)/liter, and deionized water containing 200 mg 8-hydroxyquinoline citrate (8-HQC) + 20 g sucrose (S)/liter. Flowers of different cultivars differed in fluoride sensitivity. Sensitive cultivars developed necrosis on the tips of ray florets within 12 to 24 hr of exposure to fluoridated water, whereas the least-sensitive cultivars were injured within 4 to 6 days. Petal necrosis was the prim ary factor reducing longevity in fluoridetreated flowers. Petal necrosis did not occur on flowers held in DI or 8-HQC + S. The mean postharvest lives of the 20 cultivars held in fluoridated water, DI, and 8-HQC + S were 2.6, 5.3, and 8.3 days, respectively.

Open Access

Physical properties differed significantly among five Philippine-produced coconut (Cocos nucifera L.) coir dust sources. Bulk densities ranged from 0.04 to 0.08 g·cm–3. Air-filled pore space, water-filled pore space, and total pore space ranged from 9.5% to 12.6%, 73.0% to 80.0%, and 85.5% to 89.5% (v/v), respectively. Total solids accounted for 10.5% to 14.5% of total volume, and water-holding capacities ranged from 750% to 1100% of dry weight. Significant differences existed in particle size distribution, with the largest differences occurring for particle sizes <8.0 mm and 0.25 to 0.50 mm in diameter. Chemical properties were determined for 12 sources from the Philippines, Sri Lanka, or Indonesia. The pH and electrical conductivities ranged from 5.6 to 6.9 and 0.3 to 2.9 mS·cm–1, respectively, and were significantly different among sources. No significant differences occurred among samples with respect to Fe, Mn, Zn, B, Cu, NH4-N, and Mg concentrations. Coir dust samples contained Fe, Mn, Zn, B, and Cu at 0.01 to 0.07 mg·L–1. The levels of NH4-N and Mg were 0.1 to 0.2 and 1.0 to 7.4 mg·L–1, respectively. Significant differences occurred between sources for Ca, Na, and NO3-N, with levels (mg·L–1) ranging from 1.0 to 24.3, from 22.3 to 88.3, and from 0.4 to 7.0, respectively. The widest ranges occurred in K (19 to 948 mg·L–1) and Cl (26 to 1636 mg·L–1). Sources differed with respect to cation exchange capacities, with values ranging from 38.9 to 60.0 meq/100 g.

Free access

Abstract

Reduction of irrigation level on leatherleaf fern [Rumohra adiantiformis (G. Forst) Ching] to 150 cm/year from 311 cm/year (recommended rate) had no effect on frond yield or fresh weight and increased vase life on 3 of 7 harvest dates. Nitrogen sources of urea or NH4NO3 did not affect frond yield or fresh weight, but there were some minor variable effects on vase life.

Open Access