CHANGES IN LEAVES AND STEM DIAMETER OF COCOA TREE (Theobroma cacao L.) IN DROUGHT STRESS

Abstract

In general, research on plant drought response of cocoa has been done mainly on seedlings. However, information about the response of cocoa tree to drought stress is still very small. The purpose of this resesrch to study the change in leaves number per branch, leaf mass per area ratio (LMA) and stem diameter of the 6 years old cacao tree before and during drought stress period. Drought stress treatment with through fall displacement experiment (TDE) system which is a treatment with through fall displacement experiment (TDE) system which is a method of usng the roof panels plastic are placed under the canopy of trees where the roof can be opened and closed. Experimental design used in this study was completely randomized design with factorial treatment between drought stress treatment (no stress/control; drought stress (roofing) and time (month of sampling). Three designated as a control plot (plot of non-roofing), and three plots defined as a plot roofing. Measurement of variables made on each plot by randomly selecting six cacao trees. The result showed that drought stress with TDE system does not influence to the leaf number per branch, leaf mass per area ratio, and stem diameter of cocoa tree even though that TDE system effectively reduce infiltration of rainwater into the ground, however, soil water content decreased by 30% had no effect on cocoa crop growth aged 6 yers. The growth of cocoa plants before and during drought stress showed the leaves number per branch increased from 17.18 to 38.88 leaves; LMA values are relatively constantly is 8.7 mg/cm2 and cocoa stem diameter increased from 29.72 cm to 33.67 cm