part_of part of part of whole plant development stage life of whole plant stage sporophyte development stage PO_GIT:139 sporphyte phase (exact) sporophytic phase (exact) PO_GIT:68 sporophytic development stage (exact) A whole plant development stage (PO:0007033) that has as primary participant a whole plant (PO:0000003) during the interval between fertilization (or apogamy) and death.