Why does the watermelon have a Mercedes-Benz mark?

The hollow fruit phenomenon. ①Climate. Generally, when encountering drought or low temperature, the internal nutrient supply of watermelon is insufficient, the surrounding areas of the seeds cannot expand naturally, the rate of cell division slows down, and the number of cells in the fruit is insufficient. If high temperatures are encountered for a long time in the later stages of growth, the peel will continue to develop and it is easy to form a transverse hollow fruit. ②Moisture. During the fruit expansion period, there is severe drought and water shortage, and the cells in the fruit cannot fully expand, resulting in hollow fruits. During the fruit development and maturity period, if you water too much, the surrounding areas of the seeds have already matured, while the other part of the pulp tissue continues to develop, resulting in uneven development and the formation of vertically broken hollow fruits. ③Harvesting time. Under normal growth conditions, nutrients and water will be continuously transported to the fruit. If they are not harvested in time after maturity, the backflow of nutrients and water will often occur, resulting in hollow fruits.