Fruit is necessary in food, although each person has their preferences and tastes. The apple is usually one of the most consumed for its flavor, but we do not pay attention to its appearance.
Have you ever wondered why you have a dimple on the cusp? If it really hangs from the tree, why isn’t it a more elongated shape? Science has revealed in a study why it acquires that shape and has a dimple-shaped cusp.
The growth of the apple gives that shape
Basically, this physiognomy is the result of the different growth phases between the mass and the stem, according to the new mathematical study of the fruit. Apples are relatively spherical apart from the dimple on the top. But, a team from Harvard University in Cambridge set out to see if they could understand why the fruit has such an unusual shape.
The scientists used a gel that could adapt that shape over time. This helped to replicate the way an apple grows, and they compared it to the growth of real apples in an orchard. Combining this with mathematical modeling revealed that the underlying anatomy of the fruit – the way it grows at different rates and mechanical instability – play a joint role in dimple elevation, lower ridges, and the overall shape of the fruit.
Dr. Lakshminarayanan Mahadevan, the lead author of the study, had previously developed a simple theory to explain the shape and growth of apples. However, the project began to pay off when the researchers were able to connect observations of real apples at different stages of growth.
A mathematical theory solves the unknown
To understand the evolution of the apple and cusp shape, the researchers turned to a long-standing mathematical theory known as the singularity theory .
The singularity theory is used to describe a number of different phenomena. This can be used to learn about black holes or more abstract examples, such as light patterns at the bottom of a pool and the propagation of cracks. ” These focal points can sometimes take the form of singularities where the deformations are located ,” said the author, adding that ” a ubiquitous example is seen at the cusp of an apple, the inner dimple where the stem meets the fruit. “.
The team of researchers suggests that the peculiarity in this case is a slight alteration in the growth speed around the stem , compared to other parts of the apple, creating a dimple. The cusp of the block has nothing in common with the light patterns in a pool, but it is the same shape as them.
The team used numerical simulation to understand why the growth of the fruit’s rind and core form a cusp. Then, they corroborated the simulations with experiments that mimicked apple growth using gel that swelled over time. The experiments showed that different growth rates between most of the apple and the stem region resulted in the dimpled cusp .
These changes and cusp shapes are seen in some apples and other fruits, such as peaches , apricots , cherries, and plums . The team found that fruit anatomy can have joint functions by giving rise to multiple cusps in all similar fruits.
The authors say that the nature of the molecular signals that trigger inhibition of growth near the stem should be explored in the future. They also want to look at the mechanisms that relate cells to changes in the fruit’s tissues.
