Apples fall from trees due to the force of gravity. When apples ripen, they become heavier and eventually detach from the tree, falling to the ground.
If apples fall to the ground, it is primarily because the planet exerts on them a force of attraction called gravity. More specifically, the Earth attracts everything towards its center, and thus also the apples in their tree. As long as the apple remains attached to the branch, this terrestrial attraction is counterbalanced by the resistance of the peduncle, but as soon as it weakens or breaks, it heads for the ground! This force of gravity is directly related to the mass of objects; the more massive an object is, the stronger the attraction. It is therefore because of gravity that the apple inevitably ends up on solid ground, and no one has ever seen an apple gently float towards the sky.
When an apple ripens, it prepares the ground for its detachment through a special area: the abscission zone. To put it simply, it's a layer of cells at the base of the stem that gradually becomes fragile. As the apple reaches maturity, these cells soften, their walls weaken, and they separate easily. The result is that the connection between the branch and the fruit thins and eventually breaks without any particular effort. This natural process is influenced by the action of the plant hormone called ethylene, but also by the decrease of other hormones like auxin, both of which are essential in regulating this zone. Once the connection is sufficiently weakened, a gust of wind or just the weight of the fruit will cause the apple ready to be harvested to fall.
The weather clearly affects the dropping of apples. When temperatures fluctuate significantly, swinging from intense heat during the day to marked cold at night, it stresses the fruits, which can fall prematurely. A strong gust of wind or heavy rain can also trigger a fairly massive drop within a few hours. Conversely, prolonged drought alters the tree's water supply, reducing its nutrient intake and promoting the rapid appearance of the famous abscission zone, where the fruit detaches. Additionally, a late frost episode in spring weakens young fruits, making their drop common a few weeks later. In short, temperature, wind, precipitation, and even drought periods largely determine whether an apple will remain firmly attached or ultimately fall prematurely.
Ethylene is somewhat the key trigger for apple drop. This gaseous hormone is naturally produced by apples as they ripen, akin to a signal that tells the apple, "Okay, it’s time to let go." Essentially, as apples reach maturity, ethylene accumulates, activating the formation of a weak zone at the base of the fruit called the abscission zone, and speeding up the separation of the apple from its stem. The riper an apple becomes, the more ethylene it produces, leading to a chain reaction where one ripe apple can also accelerate the ripening and dropping of neighboring fruits. This is also why a perfectly ripe apple placed next to other fruits in your bowl will make them ripen faster.
Pests like wormy apples (codling moth larvae) seriously weaken the apple by boring galleries into it. As a result, the injured apple falls earlier than expected. Certain diseases, such as scab or downy mildew, damage the surface of the apples and injure the internal tissues. Weakened by these attacks, the apples easily detach from their branch with the slightest gust of wind. In short, diseases and pests play a direct role in the premature dropping of fruit.
Did you know that ethylene, a plant hormone involved in the ripening of apples, is also commercially used to artificially initiate the ripening of various fruits such as bananas and avocados?
Severe weather conditions such as strong winds or hail can accelerate the premature dropping of apples, sometimes seriously damaging farmers' crops.
Did you know that fruit trees, such as apple trees, naturally shed some of their fruits to focus on the growth of the remaining ones? This process, known as natural thinning, allows the remaining apples to grow larger and taste better.
Although we often associate the red apple with ripeness, some varieties of ripe apples remain completely green or yellow. Therefore, the dropping of the fruit is not always a reliable sign of complete ripeness.
Some apples may remain attached to the tree due to a low ethylene level or incomplete development of the abscission zone. Specific climatic conditions or certain varieties can also influence this phenomenon.
A drop of apples caused by a disease is often characterized by visible symptoms such as dark spots, apparent rot, or deformation of the fruit. In case of doubt, it is advisable to consult a specialist.
It depends: if the apple has fallen recently and shows no damage or rot, it is edible. However, damaged apples with blemishes or a suspicious smell should be avoided.
The best time for picking depends on the variety of apples and their intended use (immediate consumption or storage). Generally, the color, firmness, and ease of detachment of the fruit from the branch indicate that it is ready to be harvested.
Yes, it is possible to reduce the early drop of apples by controlling pests and diseases, regularly watering the tree, and avoiding stressful situations such as drought or nutritional deficiencies.
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