Leaf anatomy related to photosynthetic pathway in coffee trees (Coffea arabica L.,var. Caturra Rojo) exposed to different solar radiation levels at Sierra Maestra, Granma, Cuba

A field experiment was conducted in order to investigate the effect of different solar exposition levels (open sunlight, regulated shade, and no regulated shade) on leaves anatomy of coffee trees (Coffea Arabica L. Var. Caturra Rojo) at the Sierra Maestra- Granma, Cuba. Histological and morphological leaf studies were made related with leaf area, leaf, palisade and spongy parenchyma thickness, thickness of abaxial and adaxial epidermis, number and dimensions of stomata. In open sun light conditions, the coffee trees showed some adaptation features characterized by a slower leaf area, an increasing of leaf area, palisade parenchyma and the epidermis thickness and higher stomata frequency. In all three solar exposition levels a greater chloroplasts quantity around the bundle sheet cells were observed. The growing of individual leaves was related to the rain independently from the exposition levels to the sun. The leaves of coffee plants growing under an open sunlight exposition showed the lower leaf area. The leaves growing during the hotter months while fructifying showed the smallest size