Changes in pigments, chlorophyllase activity, and chloroplast ultrastructure in ripening pepper for paprika

Two typical cultivars of pepper for paprika (Bola Roja of red fruits and Negral of brownish fruits) were analyzed for pigments, chlorophyllase activity, and plastid ultrastructure. Three ripening stages were considered: green, unripe (changing color), and fully ripe. Fully ripe peppers of the Negral cultivar retained chlorophyll, while in the Bola Roja fruits this disappeared at the end of maturation. Chlorophyllase activity was higher in the cv. Negral at the first two ripening stages, and similar in both cultivars at the fully ripe stage. Plastids of the early ripening stage were characterized by the typical grana-intergranal structure and a highly developed peripheral reticulum. In the last stage, plastids presented massive structural reorganization. All of these differences among both cultivars are discussed.