Effects of temperature during fruit growth and maturation on pigmentation of purple cherry tomato containing a functional anthocyanin

Abstract: Anthocyanins are natural pigments distributed widely among higher plants. Anthocyanins in plant-derived food are also important nutrient constituents, due to their dietary health benefits. Tomato (Solanum lycopersicum L.) is an important vegetable crop grown worldwide, many with anthocyanins in their fruit tissues, but the pigmentation varies specially in the popular purple tomato. To develop tomatoes with a high anthocyanin content, we conducted cultivation experiments under natural temperature and sunlight conditions using two purple cherry tomato cultivars ‘Toscana Violet’ and ‘Blue Bingo’ and an ordinary cherry tomato cultivar ‘Amakko’ as a control to clarify problems which we may encounter during year-round cultivation of purple tomatoes. The content of anthocyanins was high in the tomatoes cultivated in the winter but extremely low in those cultivated in the summer. These findings suggested that the high temperature in summer may cause poor anthocyanin production resulting in less pigmented fruits, although the yield of fruits itself is not be affected greatly. Furthermore, treatment of ‘Blue Bingo’ fruits at late growth and maturation stage by a night (8 h)-and-day (16 h) temperature regime of 15-22 ?C resulted in marked accumulation of anthocyanins in skin and outer pericarp of the fruits, but those of 20-27 ?C and 25-32 ?C had no or little accumulation.