Moreover, a variety of other protein species were identified,
such as the chloroplast photosynthetic water oxidation
complex, oxygen-evolving complex protein 1, and chloroplast
manganese stabilising protein-II. All of these protein species
are involved in Photosystem II, which is the first protein
complex involved in the light-dependent reactions. In this
system, the energised electrons are replaced through the
oxidation of water to form hydrogen ions and molecular
oxygen [37]. Again, through the activity of the enzymes
involved in combating ROS and due to the dynamics of these
ions [38,39], one can hypothesise that oxygen species are
present in high amounts in such plants, which was corroborated
by the identification of a high number of enzymes such
as CAT, GPX, APX, and GR. Additionally, the hydrogen ions
thus generated are used by the ATPase to generate ATP. In
fact, the ATP synthase beta subunit was also identified as a
differentially abundant protein in the plants evaluated in this
work.