Why do broses start black and then turn yellow?

Broses, or the buds of certain plants, often start as black due to a buildup of anthocyanins, which are pigments that can appear dark. As the buds mature and the plant undergoes changes in light exposure and temperature, these pigments can break down or change, resulting in a yellow coloration. This transition can also be influenced by the plant's health and environmental conditions. The change serves various purposes, including attracting pollinators or signaling ripeness.