Low temperatures also affect the development of chlorosis in coffee leaves and, depending on the growth stage,the damage is irreversible when chloroplast destruction is observed. Nevertheless, there seems to be a strict relation between the carbohydrate content and the development of injuries (Franco 1970), which could be directly associated with the maintenance of leaf water potential and a lower freezing temperature. Some adaptations to tolerate light energy and excess temperature are leaf curvature and thick ening, mainly due to the cuticle thickness. Compared to shaded coffee plants, those exposed to full sunlight have 11% thicker leaves (Fahl et al. 1994).