Question

why transpiration and photosynthesis is compromise

Answer 1

 By closing stoma to conserve water, the diffusion of atmospheric CO2 into the leaf for carbon fixing is compromised. Productivity in the plant is therefore limited by the need to retain water. Closing stoma also builds up O2 from the light reactions in the leaf

Answer 2

Photosynthesis and transpiration both are a compromise for a plant. ... Photosynthetic plants that are active requires lots of water and the water demand is so high that it gets depleted through the transpiration process very quickly...