Articles
ENVIRONMENTAL INFLUENCES ON TISSUE RESPONSES TO TWO BLOOM THINNING COMPOUNDS USING CHERRY LEAVES AS A MODEL SYSTEM
Article number
527_10
Pages
95 – 104
Language
Abstract
A common problem in using chemical thinners to regulate crop load of fruit trees is inconsistent activity under varying environmental conditions.
A goal of this study was to develop controlled methods for comparing environmental effects on plant responses to chemical thinners.
Cherry leaves were used as a model system to study two types of bloom thinners: ammonium thiosulfate (ATS) and a penetrating surfactant (‘Armothin’, Akzo Nobel Chem.). Generation of ethylene continued to increase with increasing rate of Armothin, but ATS applied at rates above 1% reduced ethylene biosynthesis.
Both Armothin and ATS caused direct injury, measured as stress ethylene generation, when the compounds were applied at 5% and 1%, respectively, and drying of the compound was prevented.
Additional ethylene generation resulting from desiccation stress after 15 minutes of drying (prior to ethylene assay) with Armothin, but no additional ethylene was generated from ATS-treated leaves with up to 60 minutes of drying.
Armothin activity was less responsive to temperature than was ATS. Ethylene generation plateaued over 25; to 35°C for Armothin, but ATS required temperature between 30° and 35°C for similar response.
Leaf desiccation rate was increased over controls by increasing concentration of Armothin, but not by ATS at 1%. Our results suggest that Armothin injures tissue by both direct damage to tissue and by indirect desiccation stress, while tissue damage from ATS is due to direct toxicity.
Our results also provide quantitative confirmation of the impression from field observations that activity of Armothin is more stable to variation in temperature than is ATS.
A goal of this study was to develop controlled methods for comparing environmental effects on plant responses to chemical thinners.
Cherry leaves were used as a model system to study two types of bloom thinners: ammonium thiosulfate (ATS) and a penetrating surfactant (‘Armothin’, Akzo Nobel Chem.). Generation of ethylene continued to increase with increasing rate of Armothin, but ATS applied at rates above 1% reduced ethylene biosynthesis.
Both Armothin and ATS caused direct injury, measured as stress ethylene generation, when the compounds were applied at 5% and 1%, respectively, and drying of the compound was prevented.
Additional ethylene generation resulting from desiccation stress after 15 minutes of drying (prior to ethylene assay) with Armothin, but no additional ethylene was generated from ATS-treated leaves with up to 60 minutes of drying.
Armothin activity was less responsive to temperature than was ATS. Ethylene generation plateaued over 25; to 35°C for Armothin, but ATS required temperature between 30° and 35°C for similar response.
Leaf desiccation rate was increased over controls by increasing concentration of Armothin, but not by ATS at 1%. Our results suggest that Armothin injures tissue by both direct damage to tissue and by indirect desiccation stress, while tissue damage from ATS is due to direct toxicity.
Our results also provide quantitative confirmation of the impression from field observations that activity of Armothin is more stable to variation in temperature than is ATS.
Authors
W. C. Olien, C. S. Knight
Keywords
Prunus persica, Prunus yedoensis, ammonium thiosulfate, Armothin, desiccation, ethylene, temperature
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