Question

what do plants use as a source of their hydrogen for photosynthesis

Answer 1

water

Answer 2

^ Yup! In photosystem II, water is oxidized via photolysis to yield electrons, hydrogens, and an oxide ion.
\[H_2O + 2 \space photons \space (light) \rightarrow 2e^{-} + 2H^{+} + O_{2}^{-}\]

Answer 3

The metabolism of plants is done through chemical and biochemical processes. They use the water, and sunlight to split water into hydrogen and oxygen, allowing photosynthesis to occur.
source-> search
Hope this helps.

Answer 4

Rogue it is more accurate to describe it as:
\[Q + 2 H _{2}O + hv \rightarrow Q _{2} + 2QH _{2}\]
Q is plastoquinone. QH2 the reduced form.

Answer 5

Superoxide anions O2- is actually harmful to photosystem II.