Hobbies And Interests
Picked
Lemons and other picked fruit begin to rot as soon as they are picked. In the case of a lemon, the picking is done from a lemon tree. Most fruit, if left unpicked, will eventually rot on the vine or fall to the ground and rot there. The act of picking severs the connection between the fruit and the plant, speeding up the rotting process.
Ripening
Most commercially grown fruits are picked at the optimal time to allow as large a time window as possible in which the fruit will be palatable, and therefor marketable to customers. Most fruits, such as lemons, are picked before they are ripe, and are allowed to ripen while being transported to customers. Physiological processes such as softening of the fruit tissue and sugar conversion continue, and are necessary to bring a fruit to full ripeness.
Natural Aging
Some fruits that are not consumed will eventually succumb to what is considered natural aging, which is often simply a continuation of the ripening process. As fruits ripen, for example, they become softer, and this physiological process may continue to the point where the fruit tissue is significantly degraded, and is unpalatable. The fruit may still be safe to consume, but might be considered rotten by most people.
Disease
As fruits such as lemons age, they also succumb to a variety of infections, such as fungus, that make the fruit not only unpalatable, but also unsafe to eat. A wound that penetrates the skin of a lemon, for instance, may introduce fungus or some other infection. Latent pathogens that penetrated the fruit early in its developmental stage may also become activated as the fruit begins to break down, causing the fruit to rot.