An increase in the oxygen
concentration in many plants results in a
decrease in the rate of photosynthesis. This
phenomenon of the inhibition of photosynthesis
by O2 was first discovered by a German
biochemist Warburg in 1920 in Chorella (a green
alga) and is called Warburg effect. O2 causes
greatest inhibition of photosynthesis when CO2
levels are low and light levels are saturating.
This effect is known to occur in C3 plants
(Soyabean) and C4 plants (Sorghum, Maize,
Sugarcane), etc.