Help cure lemon tree.

My young lemon tree (its age about 5 month) gives new suckers but leaves don't grow correctly. The new leaves of lemon tree is small, wrinkled with visible veins. If you know what is it please write me. Thank you.

 

Overwatering can cause leaf curl let it almost dry out between waterings.

 

Plant roots look healthy, but leaves look very little and sick. I can't understand the reason that.