$C_{4}$ plants show kranz type of anatomy. In kranz anatomy, the mesophyll is undifferentiated and its bundle sheath cells occur in concentric layers around vascular bundles. First stable product in $C_{4}$ plant is $OAA$ (oxaloacetic acid). $OAA$ is reduced to malic acid in mesophyll cells. There is little loss of photosynthetic activity on account of photorespiration as it is absent in $C_{4}$ plants. In $C_{4}$ plants, photosynthesis is appreciable even under water stress