HORTICULTURE

Detailed explanation-1: -Both photosystems contain many pigments that help collect light energy, as well as a special pair of chlorophyll molecules found at the core (reaction center) of the photosystem. The special pair of photosystem I is called P700, while the special pair of photosystem II is called P680.

Detailed explanation-2: -P700, or photosystem I primary donor, is the reaction-center chlorophyll a molecular dimer associated with photosystem I in plants, algae, and cyanobacteria.

Detailed explanation-3: -The reaction center chlorophyll (or the primary electron donor) of photosystem II that is most reactive and best in absorbing light at wavelength of 680 nm. P680 is a group of pigments that are excitonically coupled or that act as if the pigments are a single molecule when they absorb a photon.

Detailed explanation-4: -The primary electron donor of photosystem I, P700, is a chlorophyll species that in its excited state has a potential of approximately-1.2 V.