( ( Variability ( in ( new ( root production ) ) ) ) ( ( ( was ( more ( than twice ) ) ) ( that ( in ( leaf production ) ) ) ) ; ) )
(ROOT (S (NP (NP (NNP Variability)) (PP (IN in) (NP (JJ new) (NN root) (NN production)))) (VP (VBD was) (ADVP (RBR more) (IN than) (RB twice)) (NP (NP (DT that)) (PP (IN in) (NP (NN leaf) (NN production))))) (: ;)))
Variability in new root production was more than twice that in leaf production;
(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))))) (. .)))