The ovary of an orange is actually composed of multiple carpels. Generally speaking, there are several carpels and an orange has several petals. In the early stage of flower and fruit development, many carpels are adhered together by cells. When the fruit ripens, the cells located in the middle of interventricular septum and attached to different carpels begin to expand, vacuolate and eventually die, leaving only a thin cell wall; The cells on both sides of the interventricular septum thicken the cell wall and become tough "membranes". This has caused the orange petals that were tightly stuck together to become loose and easy to separate. When orange petals separate, the cell wall structure connecting different orange petals is actually destroyed. Then, of course, after tearing it up, you can't put it back together. After separating the orange petals and carefully observing the surface of the membrane, you will find many small white fluffy structures, which are actually the cell walls of damaged expanded cells.