exacting
adj.
having complicated nutritional requirements; especially growing only in special artificial cultures
fastidious microorganisms|certain highly specialized xerophytes are extremely exacting in their requirements
Synonym: fastidious
adj.
severe and unremitting in making demands
an exacting instructor|a stern disciplinarian|strict standards
Synonym: stern, strict
adj.
requiring precise accuracy
an exacting job|became more exigent over his pronunciation
Synonym: exigent