C4 plants preferred in tropical region because:
(i) They consume 30 ATPs (12 ATPs more than C3 plants) to produce one molecule of glucose favoured in tropical region.
(ii) In these plants photorespiration is the mechanism not to lose the photosynthetic carbon.
(iii) In the process of photorespiration, RuBP is catabolised to a 3-carbon atom compound instead of combining with CO2.
(iv) More than 50% CO2 fixed by photosynthesis is lost in photorespiration.
(v) Photorespiration acts to undo the work of photosynthesis as no energy rich compound is produced during this process.
(vi) Thus C4 plants are better photosynthesizers than C3 plants and C4 pathway is of adaptive advantage in tropical region and thus these plants are preferred.
