Morphological, anatomical, and ultrastructural changes in Vaccinium corymbosum fruits during ontogeny

Abstract

Given their attractive appearance and flavour, as well as high antioxidant content, Vaccinium corymbosum L. fruits are greatly appreciated by consumers. These quality traits are primarily dependent on pomological characteristics of the cultivar. Vaccinium corymbosum ‘Bluecrop’ is one of the most popular and valuable cultivars of highbush blueberry; however, its fruits become soft shortly after harvesting. Changes in the fruit structure and in the content of phenolic compounds and, in particular, emergence of some traits related to fruit firmness and shelf life, were analysed in the surface layers of ‘Bluecrop’ fruits from the stage of flowering through the fruit set stage to harvest maturity using light microscopy, transmission electron microscopy, and scanning electron microscopy. The study involved investigations of qualitative and quantitative changes in the development and microstructure of epicuticular wax, cuticle, epidermis, hypodermis, and stone cells, and analysis of the presence of tannins and anthocyanins. Moreover, it was found that the development of many traits associated with fruit firmness and shelf life started in the initial period of ontogeny. These results can be useful for the researchers developing new cultivars in detection of early manifestations of developmental features of specific quality traits and in comparative analyses of blueberry cultivars differing in fruit firmness and shelf life.