The possible role of abscisic acid and cytokinins in growth rhythms of Theobroma cacao L.
Abscisic acid was identified in extracts of cacao buds by combined gas-liquid chromatography/mass spectroscopy. Cytokinin activity was detected in these extracts by biological assay. Both hormones were found to vary in concentration in response to defoliation treatments. ABA levels in the leaves increased following depletion of soil moisture. The possible role of these hormones in the control of bud growth is discussed. It is suggested that a feed-back inhibition may operate in cacao and other species of intermittent growth, in that shoot growth can eventually become limited by a critical leaf area. According to this hypothesis, internal moisture stress, which appears to be a prerequisite for synchronous flushing of cacao under field conditions, would trigger the: hormonal control of bud growth, thanks to its effect on leaf shedding or on the formation of abscission layers
| Main Authors: | , , , |
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| Format: | biblioteca |
| Published: |
1974
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| Subjects: | THEOBROMA CACAO, SUSTANCIAS DE CRECIMIENTO VEGETAL, ETAPAS DE DESARROLLO DE LA PLANTA, ACIDO ABSCISICO, CITOCININAS, BRASIL, |
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| Summary: | Abscisic acid was identified in extracts of cacao buds by combined gas-liquid chromatography/mass spectroscopy. Cytokinin activity was detected in these extracts by biological assay. Both hormones were found to vary in concentration in response to defoliation treatments. ABA levels in the leaves increased following depletion of soil moisture. The possible role of these hormones in the control of bud growth is discussed. It is suggested that a feed-back inhibition may operate in cacao and other species of intermittent growth, in that shoot growth can eventually become limited by a critical leaf area. According to this hypothesis, internal moisture stress, which appears to be a prerequisite for synchronous flushing of cacao under field conditions, would trigger the: hormonal control of bud growth, thanks to its effect on leaf shedding or on the formation of abscission layers |
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