( ( Gibberellins production ) ( ( ( occurs mainly ) ( in ( ( ( the roots ) and ) ( young leaves ) ) ) ) . ) )
(ROOT (S (NP (JJ Gibberellins) (NN production)) (VP (VBZ occurs) (ADVP (RB mainly)) (PP (IN in) (NP (NP (DT the) (NNS roots)) (CC and) (NP (JJ young) (NNS leaves))))) (. .)))
Gibberellins production occurs mainly in the roots and young leaves.
(ROOT (S (NP (JJ Young) (NNS roots) (CC and) (NNS leaves)) (VP (VBP are) (NP (NP (DT the) (JJ major) (NNS sites)) (PP (IN of) (NP (NN gibberellin) (NN production))))) (. .)))