May interact with bacterial adhesins thereby protecting the reproductive tissues from microbial attack. Has no oxalate oxidase activity. 2 H(+) + 2 superoxide = H2O2 + O2 Binds 1 Mn(2+) ion per monomer. Monomer. In the absence of manganese, it forms tetrameric and pentameric forms which show superoxide dismutase activity. Found in the nectar. Nectary tissues and to a lower level ovary. Not detected in petals, stems, leaves, roots or other floral tissues. Expressed during nectar secretion, while the flowers remain open. Belongs to the germin family.