Sweet cherry development is a fascinating process that determines the size, structure, and quality of the fruit we harvest. By understanding the stages of sweet cherry fruit growth, from flowering to seed and pit formation, growers can better manage orchards and improve yield.
How Does a Cherry Move from a Flower to the Fruit We Harvest?
This infographic outlines the main stages of fruit development in sweet cherries, focusing on how the different fruit tissues form and grow over time.
The process begins with flowering, when the plant produces flowers containing the ovary with ovules. After successful pollination and fertilisation, sweet cherry development begins, and the ovary grows into a young fruit.
Seed & Pit Formation (Stage I)
During Stage I, the ovary develops into a young fruit and the basic fruit structure is established. The pericarp begins to form, consisting of:
- Exocarp, the outer skin
- Mesocarp, the flesh
- Endocarp, the inner layer surrounding the seed
At this stage, both the cherry pit and seed formation begin, and early development of the fruit tissues takes place.
Endocarp Formation (Stage II)
In Stage II, the inner cells of the endocarp lignify and form a hard shell around the seed. This structure becomes the pit that is commonly removed when eating a cherry. During this stage, the fruit continues to grow, while the pit hardens and defines the inner structure of the fruit.
Mesocarp Development (Stage III)
During Stage III, flesh cells enlarge and accumulate sugars, water and nutrients, forming the edible part of the fruit.
By the end of these stages, the fruit has its full structure: a seed enclosed by the endocarp, surrounded by the mesocarp, and protected by the exocarp.
But what happens when this delicate structure is exposed to water at the wrong moment?
From Fruit Growth to Fruit Cracking
Did you know that the outermost skin layer of a sweet cherry, called the cuticle, which is a thin protective layer covering the exocarp, is only about 1 micrometer thick? That’s much thinner than a human hair, which measures between 4 and 12 micrometers. When water collects on the fruit’s surface or the air is very humid, tiny cracks can form in the cuticle. These microcracks are invisible to the naked eye but can be seen under a microscope. Microcracks are the first step toward the larger cracks.
Cracking in sweet cherry fruit is a sequence of events. Cuticle deposition ceases at the end of stage II, when the fruit has a mass of about 2–3 g. By the end of stage III, the fruit typically reaches about 10–12 g. As a result, the existing cuticle is subjected to high strain and becomes very thin, like a balloon.
Water on the fruit surface, or even high humidity, can induce microcracks in the cuticle. During rainfall, water may enter the fruit uncontrollably through these microcracks. The water moves along the skin tissues (epidermis and hypodermis) into the flesh cells, which have a strongly negative osmotic potential due to their high sugar content, meaning that water is naturally drawn into the cells. However, these flesh cells have thin and unstable cell walls and may rupture once water enters.
The ruptured cells release their contents into the apoplastic space (the space between cells). Not only sugars but also acids, especially malic acid, are released. This acid weakens the cell walls of neighbouring cells, making them more prone to failure. As long as water continues to enter the fruit, progressively more cells rupture.
At a critical point, the tissue can no longer withstand the high strain in the fruit skin, and a microcrack develops into a macrocrack, making the crack visible. As water uptake continues, this process persists and the crack elongates. This is why cracking remains a major challenge in orchards.
Where CrackSense Comes In
Fruit cracking is a major issue in orchards because it directly reduces fruit quality and marketability, leading to significant economic losses and contributing to food waste. Cracking not only affects the appearance of the fruit but also increases its susceptibility to pathogens, further compromising yield. Growers must constantly manage environmental factors such as irrigation, humidity, and rainfall, but traditional monitoring methods are often manual, time-consuming, and reactive, making it difficult to prevent cracking before it occurs.
CrackSense aims to address this challenge by progressing through multiple development stages, shifting from manual monitoring to high-throughput, real-time, proximal, and remote sensing tools integrated with advanced agri-environmental monitoring. The data gathered from experiments will be scaled up and applied at several pilot sites across two continents, enabling the prediction of fruit cracking intensity at the plot, regional, and yearly levels.
Understanding sweet cherry development and the stages of sweet cherry fruit growth is essential for improving orchard practices and fruit quality. To follow the latest advancements and learn more about the project, we encourage you to follow us on LinkedIn and read our articles on Newsroom, where we regularly share updates on our progress.