Search Results

You are looking at 1 - 10 of 10 items for

  • Author or Editor: Stanley Ries x
Clear All Modify Search
Authors: and

Abstract

Triacontanol (TRIA) is synthesized by plants and is a component of most biological material. New formulations of TRIA have shown activity with femtomolar doses. Although the majority of TRIA in plants is bound to (and is located in) the cuticle, small amounts can be found in parenchyma tissue. Exogenous applications of TRIA regulate directly or indirectly several physiological and biochemical processes. Many studies have shown that TRIA can increase the yield of crops, but the results have not been sufficiently consistent in the United States to recommend its use commercially. Several experiments suggest that TRIA, a metabolite of TRIA, or a secondary messenger, moves rapidly in plants after initial application. Changes in the levels of several metabolites and the optimum environmental conditions for treatment indicate that carbohydrate metabolism may be involved in the plants’ response to TRIA. Additionally, several enzymes relating to carbohydrate metabolism increase in activity following TRIA treatment. Warm temperatures before foliar applications improved the plants response to TRIA. Many compounds have an antagonistic effect on the response of plants to TRIA. The most significant are phthalate esters, which commonly occur in water and the research environment. This contamination may explain the inconsistent results encountered by several researchers in the laboratory and field. TRIA has elicited many growth responses in plants with a rapidity not shown for other plant hormones or growth regulators.

Open Access

Abstract

Sap collected from trees of sugar maple (Acer saccharum Marsh.) in the springs of 1978, 1980, and 1981 was analyzed for 1-triacontanol (TRIA) content. TRIA was present at physiologically active concentrations which varied quadratically with sampling time during each spring season. The maximum TRIA concentration observed was about 11.4 × 10-9M. The highest concentration of TRIA in the sap shifted each year of collection.

Open Access

A methanol: water extract of tomato (Lycopersion esculentum Mill.) apices increased the growth of the alga Chlamydomonas reinhardtii. The active substance from the dried shoot apices was purified by C18 flash column and high performance liquid chromatography. The purified extract enhanced the growth of tomato, corn (Zea mays L.), and rice (Oryza sativa L.) seedlings at concentrations less than 1.0 mg·liter-1 . With Chlamydomonas, the purified extract increased cell division 111% at 0.1 mg·liter-1 and chlorophyll content 23% at 10 mg·liter-1 in 18 hours. Nuclear magnetic resonance and mass spectroscopy indicated that the purified fraction was a mixture of compounds having sugar moieties. Analysis by thin layer chromatography showed that the fraction was ninhydrin positive and more polar than the known plant hormones studied.

Free access

Abstract

Vegetable and field crops were grown on young residues of several cultivars of sorghum (Sorghum vulgare Pers.) in the greenhouse and field. Seedling growth of field corn (Zea mays L.) in the greenhouse was increased by residues of sorghum shoots, but not by residues of sorghum roots. In contrast the growth of sweet corn in the field was always decreased by residues of ‘Bird-a-Boo’ sorghum roots and whole plants. The growth and yield of snap beans (Phaseolus vulgaris L.) in the field was increased or decreased by sorghum residues depending on the sorghum plant part, quantity, cultivar, and soil environment. Although sorghum residues may stimulate crop growth in some instances, this stimulation was not easily controlled because the optimal range of sorghum residues and soil environment is too narrow and unpredictable.

Open Access

Several plant species that are not consumed by animals were collected, extracted with organic solvents, and tested at different venues for their effectiveness as animal feeding repellents. Species with the most repellent activity were daffodil (Narcissus pseudo narcissus), bearded iris (Iris sp.), hot pepper (Capsicum frutescens), catnip (Nepeta cataria) and peppermint (Mentha piperita). Considerable effort was expended to isolate and identify compounds from these species responsible for repellent activity. Eight chemicals have been isolated and purified, and four of them have been identified. Both daffodil and catnip contain more than one repellent, but none of the four compounds identified were common to both species. Combinations of extracts from more than one plant species proved to have more repellent activity than extracts from individual species used alone. In several tests these plant extracts proved to be as effective or better than available commercial repellents. A plethora of additives and surfactants were tested to increase repellent activity by enhancing the spreading, penetration or persistence of the extracts.

Full access

Abstract

Inconsistent yield increases in the United States have prevented recommending triacontanol (TRIA) for commercial application. Based on tests over several years, TRIA is recommended for use on many vegetable and agronomic crops in most provinces in the People's Republic of China. Their formulations were shown either to be less effective or no better than the colloidal dispersion developed by the Procter and Gamble Co. TRIA dispersions passed through 2 standard field sprayers and 3 of 5 experimental small-plot sprayers lost at least 37 % of their activity as measured by the increase in maize (Zea mays L.) seedling growth. Hexane extracts of water passed through sprayers and polyvinyl chloride (PVC) tubing contained more than 5 μg/liter of di-(2-ethyl)hexyl phthalate. This phthalate ester, as well as other phthalates, decreased activity of both the colloidal dispersion and emulsion formulations of TRIA at phthalate concentrations of 5 μg/liter or more. Phthalate esters are common in the environment, including water of developed countries, and are important constituents of the PVC tubing used on most American field and small-plot sprayers. Sprayers equipped with other types of hoses did not inactivate TRIA as measured by the growth of maize seedlings.

Open Access

Abstract

The yield response of crops to triacontanol (TRIA) applied as a colloidal dispersion was tested with 13 crop species in 45 field experiments over a 3-year period. Foliar application of TRIA resulted in treatment effects with 11 of the 13 crops and in 30 of the 45 experiments. The average yield increase was 14% with the optimum TRIA concentration in tests where yield was significantly increased, and was 5% over all 45 experiments. In seven experiments, significant yield decreases averaging 10% were measured with TRIA concentrations that increased crop yield of the same species in other tests. The most effective TRIA concentrations generally were 0.1 to 1.0 μg·liter−1. No particular stage of crop development for treatment was optimal for all crops. Based on the results of these studies, TRIA cannot be recommended for commercial application to crops in Michigan or similar environments. Chemical names used: 1-triacontanol (triacontanol).

Open Access

Abstract

The growth of several vegetable and field crops in the greenhouse was increased by applications of 1-triacontanol to the foliage, soil, or seed. Neither the seed nor soil treatments increased the yield of crops in the field. However, foliar sprays ranging from 5 to 500 mg/ha significantly increased the marketable yield of 7 of 10 crops tested. The average yield increase was based on comparisons of all the different rates and time of 1-triacontanol applications with untreated controls. The response of tomato, carrot and wheat seed treatments with 1-triacontanol was shown to be positively correlated with temperature at time of germination and early growth.

Open Access

Abstract

Triacontanol (TRIA), a 30-carbon primary alcohol, was shown to be a more effective plant growth stimulator when formulated as a colloidal dispersion than as a suspension in chloroform and Tween 20 or acetone naphthaleneacetic acid (NAA), and CaCl2. TRIA applied at rates of 0.1 and 1.0 μg/liter consistently increased the dry weight of maize (Zea mays L.) shoots and rice (Oryza sativa L.) seedlings in short-term greenhouse and growth chamber experiments. This application rate is 1000-fold lower than optimum levels applied with other formulations. A 99.45% pure sample of TRIA stimulated maize growth 2 times more than a sample containing 96.40% TRIA at a concentration of 0.5 μg/liter. Neither dispersion pH nor water hardness altered activity of TRIA formulated as a colloidal dispersion. It may be practical to apply TRIA with a controlled-droplet applicator in volumes of water as low as 8–11 liters/ha. The most important environmental factors evaluated for their effect on crop response to TRIA were time of day and temperature prior to spraying. In growth chamber studies, foliar application of TRIA 3 to 7 hours into the photoperiod resulted in twice the growth increase as applications made 11 hours into the photoperiod. In the greenhouse, with supplemental high intensity lamps, sprays were about twice as effective applied 11 hours (5 pm) as 3 hours (9 am) into the photoperiod. There was a positive correlation between the temperature of the growth chamber environment one hour before spraying and the response to TRIA; however, temperature of the environment for one hour after spray application had no effect on TRIA activity.

Open Access