Proline accumulation during anther development in Petunia hybrida

Accumulation of free proline within anthers of Petunia proceeds continuously from the mierospore stage to anthesis except for an intervening period when bud length is between 15 and 35 mm. The second increase in proline content coincides with the stage of anther desiccation. The metabolism of proline was studied in isolated peduncles fed [3H]proline and [14C]glutamine. Three factors appeared to be involved in elevating the proline content of the anthers: I. transport of proline from the leaves, II. transport of precursors and conversion to proline in the anthers and III. high stability of proline within the anthers.