Soluble and wall-bound activities of acid phosphatase, β-glucosidase, α-galactosidase and invertase in the ovules ofGossypium arboreum L. andGossypium hirsutum L. are implicated in the hydrolysis and translocation of substrates during pre- and postanthesis phases. The physiological functions of these hydrolytic enzymes are discussed in relation to early ovule development and cotton fibre differentiation.