The function of plant pigments in photosynthesis
That freed electron is transferred to the primary electron-acceptor molecule, pheophytin.
However, since photosystem II is the first step of the Z-scheme, an external source of electrons is required to reduce its oxidized chlorophyll a molecules. The photosynthetic action spectrum depends on the type of accessory pigments present. Photosynthesis - Part I: The thylakoid itself is enclosed by the thylakoid membrane, and within the enclosed volume is a lumen or thylakoid space.
A healing layer then forms on the stem and closes the wound, leaving the leaf scar, a prominent feature in many winter twigs and an aid in identification. The others are little bigger particles.