The leaves are a sign of freshness and tend to be even sweeter as they are harvested after they are fully ripe. Fruits generate ethylene gas when ripe. This type of plant hormone causes fruits to ripen even faster. Hormones are made in plants and animals, and even in small amounts, they have the effect of causing biochemical reactions in tissues and cells. In addition, in the presence of ethylene gas, fruit cells tend to stop ripening nearby fruit cells. Leaves are easily peeled and have almost no seeds. Juicy and rich sweetness will be a habit.
An optical sensor measures sugar content (sweetness), sourness, and internal disorders. It is an excellent device that can select only sweet and delicious fruits by shining light on each one without damaging the fruits and measuring the amount and wavelength of the transmitted light.
From NARO, it seems that the growth of new shoots and leaves is promoted and the tree vigor is strengthened by the application of carbon dioxide gas (1,250 to 2,000 ppm) in the spring for the citrus fruit “Shiranui” (“Dekopon”) cultivated in the facility. At the same time, it seems that the fruit set rate will increase. In addition, it seems that the fruit quality will be improved by applying carbon dioxide gas in autumn as well as in spring.