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  • Author or Editor: Lyle E. Craker x
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Abstract

Ethylene treatment of field harvested cranberries (Vaccinium macrocarpon Ait.) promoted red color development in the fruit. Anthocyanin production by berries in 3 different stages of maturity was greatest when the fruit was treated with ethylene in the light. Light stimulated ethylene production by the cranberry fruit.

Open Access
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Mulch, light level, and nitrogen fertilization were tested for their effects on productivity of horehound (Marrubium vulgaris L.). Yield of this plant increased under mulched conditions and with the addition of nitrogen fertilizer. Yield decreased with reduced light levels. Productivity of individual plants correlated with the number of branches per plant, leaf size, and leaf chlorophyll content. The number of branches per plant decreased with increased shading, but increased with increased nitrogen fertilization. The influence of mulch and shading on productivity could be due to the changes in soil temperature and in soil water potentials. Full-sun, high nitrogen, and mulch are suggested for optimum field production of horehound.

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Air pollution may play a role in gametophytic selection. To estimate whether such selection was occurring, pollen grains from homozygous and heterozygous tomato plants were tested under pollution stress. Homozygous pollen could be expected to respond to pollution more uniformly than heterozygous due to the identical genotype of the pollen grains. Acid rain reduced pollen germination and tube elongation in Lycopersicon hirsutum LA1777 (heterozygous) and Lycopersicon pennellii LA716 (nearly homozygous). UV-B reduced tube length of the pollen from both plants, but ozone only reduced pollen tube length of L. pennellii. The responses of these two kinds of pollen to acid rain, ozone, and UV-B appears to be same in terms of heterozygosity and stress dosages, suggesting the reduction of pollen germination and tube elongation under pollution stress may be mediated through physiological or physical alterations and not a response of different genotypes.

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Variation in light quality is known to modify plant morphology, growth, and chemical constituency in plants. In the present study, the effect of light quality on growth and essential oil composition in rosemary (Rosmarinus officinalis L.) was investigated by comparing plants receiving supplemental red (660 nm) and far-red (730 nm) with each other and with control plants not receiving supplemental light. Except for the supplemental light treatments, all plants were grown under natural light conditions in a greenhouse and received full daylight, averaging 9.23 h/day during the study. The red and far-red light treatments, given as day extensions, started daily 15 min before sunset and continued for 4 h each evening for 4 weeks. No significant differences were observed in biomass yield from the different light treatments, but far-red light caused elongation of internodes and a reduction in the number of leaves in comparison with control and red-light treated plants. Essential oil production was highest in plants grown under far-red light treatments.

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The passage of the Dietary Supplement Health and Education Act in 1994 made the use of supplements more acceptable in the U.S., increasing demand for botanicals to use in health care and maintenance. These botanicals, primarily medicinal and aromatic plants, currently represent about 25% of the dietary supplement market in the U.S. Although much of the market for botanicals traditionally has been met through collection of plants in the wild, enhanced cultivation of several species will be essential to bring standardized, quality plant materials into the marketplace.

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The cellulase in leaf abscissing abscission zones of coleus was observed to have an isoelectric point of 4.7. Ethylene promoted activity whereas IAA inhibited activity in the abscission zones as compared with untreated controls. The enzyme could be purified 130 fold with a combination of gel filtration, and anion exchange and affinity chromatography. Both silver-stained SDS-PAGE and cellulase activity-stained native PAGE exhibited 2 bands in the finally purified protein, suggesting two isozymes. The 2 protein bands with molecular weights of 56 and 62 kD were apparently monomers. A test of cellulase activity at various pHs indicated high level of activity at pH 5 and pH 7.2. Activity increased with an increase in reaction temperature to 50°C. Both isozymes appeared necessary for abscission in coleus.

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Maca (Lepidium meyenii Walp.), a root crop similar to radish, has been consumed in Peru for thousands of years as a food and medicine. Medicinally, the plant is used to increase human and livestock stamina and to ameliorate fertility problems associated with living at the high elevations in which the plant grows. The reputation of maca as a fertility and libido enhancer has increased the popularity of the plant in the United States and other Western countries. Constituents of interest in maca include fatty acids and macamides, but to evaluate the quality of maca products and raw material, fatty acid and macamide standards are required. While fatty acid standards are obtainable, macamide standards are not commercially available. In this study, one major macamide, n-benzylhexadecanamide, was synthesized with high yields using benzylamine and palmitoyl chloride as starting materials. The process, which was a relatively easy, one-step synthesis, could be used also to obtain other macamides without going through a time-consuming isolation. The major macamides in extracts of dried, ground maca sourced from vendors in the United States and Peru were identified and quantified by LC-UV/MS using n-benzylhexadecanamide as a standard compound.

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Black cohosh [Actaea racemosa L.; syn. Cimicifuga racemosa (L.) Nutt], a plant native to the eastern United States, is believed to have been used as a medicinal by Native Americans for thousands of years. Currently, the root of the species is popular as a herbal remedy for the relief of menopausal symptoms. Recent estimates suggest that over 90% of the black cohosh sold is collected from the wild, resulting in an unsustainable harvest of ≈9 million individual plants per year. This study investigated the morphological variation of the plant at the population and species levels to assist plant breeders working on domestication and government agencies responsible for conservation of the species. Examination of leaves and flowers suggest morphological of the species is relatively low, but that several populations have unique morphological characteristics.

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Plants of rosemary [Rosmarinus officinalis L. (Lamiaceae)] were grown in pots containing a soilless (1 sphagnum peat:1 perlite) or soil-based (1 sphagnum peat: 1 perlite:1 field soil) growing medium and fertilized with either 12N-5.2P-12.5K controlled-release fertilizer (CRF) at 9.0 g/pot; constant liquid fertilization (LF) with 20N4.3P-16.7K at 150 mg N/liter; constant LF at 150 mg N/liter, plus CRF at 4.5 g/pot; weekly LF at 150 mg N/liter; or weekly LF at 150 mg N/liter, plus CRF at 4.5 g/pot. Constant LF plus CRF generally reduced plant height and depressed shoot fresh weight relative to other fertilizer regimes. Essential oil content was highest in plants receiving weekly LF. Plants grown in the soil-based mix were shorter, shoot fresh and dry weight tended to be lower, and essential oil yield was higher when compared to plants grown in the soilless mix. Satisfactory growth was obtained in both media when rosemary plants were fertilized with 12N-5.2P-12.5K CRF at 9.0 g/pot or weekly LF with 20N<.3P-16.7K at 150 mg N/liter.

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Abstract

Three genotypes (‘Heinz 1350’, neglecta-1, yellow-green-5) of tomato (Lycopersicon esculentum Mill.) were grown during winter under natural light or with natural light supplemented with light from high-pressure sodium vapor (HPS) lamps (200-400 μmol·s-1·m-2). The plants were grown in sand culture with NO- 3 or NH+ 4 nutrition. Symptoms resembling Ca, Mg, K, and P deficiencies developed on the foliage of plants exposed to radiation from HPS lamps. Clustering of short branches in the lateral and terminal growing regions (yg-5) and epinasty (‘Heinz 1350’ and neg-1) developed on the shoots receiving HPS irradiation. Ethylene evolution by the three genotypes was enhanced by the supplemental lighting and NH+ 4 nutrition. Concentrations of Ca, Mg, K, and P in the shoots were lower in plants receiving HPS irradiation than in plants grown under natural light. Dry weights of shoots were increased by supplemental lighting relative to the weights of the plants receiving only natural light. Total accumulation of Ca, Mg, K, and P was not suppressed by HPS lighting, indicating that the phytotoxic effects of the lamps was not due to their effects on total nutrient accumulation.

Open Access