The measurement of plant moisture status and the development of stress in cacao

The importance of moisture status to cocoa production, the physiological behaviour of the tree, and in pest incidence on cocoa is stressed. Internal and external factors affecting the water balance and the development of moisture stress in cocoa are discussed. Some methods used to measure the internal moisture status of cocoa are described and evaluated. The pressure chamber was found to be a most useful instrument in water relations studies. The construction and use of the instrument are described in detail. Studies on diurnal changes in stem or pod diameter also gave useful information on water stress. Typical results given by the pressure chamber are presented and discussed in relation to the water balance of the plant. It was found that tensions of over 15 atmospheres frequently developed on unshaded mature cocoa during the sunny hours of the day irrespective of the soil moisture status. Daily minimum stress reflected soil water potential and maximum values were closely related to radiation intensity. Stress was highly dynamic, changing markedly within minutes. Dendrographs confirmed the existence of high daytime stress in cocoa. The practical importance of these findings is discussed in relation to cocoa agronomy, ecology and irrigation

Bibliographic Details

Main Authors:	Jones, Earl 81495, 107834 Quesnel, V.C., 56331 Chalmers, W.S., 68473 Fordham, R., 80036 Iton, E.F. eds., 79336 Hutcheon, W.V., 97646 Murray, D.B., 5330 Cocoa Research Institute, St. Augustine (Trinidad y Tobago), 4. International Cocoa Research Conference St. Augustine (Trinidad y Tobago) 8-18 Ene 1972
Format:	biblioteca
Published:	St. Augustine (Trinidad y Tobago) 1972
Subjects:	THEOBROMA CACAO, CONTENIDO DE HUMEDAD, BALANCE HIDRICO, TENSION DE ABSORCION, STRESS, RELACIONES PLANTA AGUA,
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