Red nectar presentation and characterization of the breeding system of an Andean nightshade

Flowers of Jaltomata weigendiana (Solanaceae) secrete red nectar that is visible through the partially translucent corolla. We report the pattern of nectar presentation during the sexual phases of the flower and characterize the breeding system. Comparison of flower sets experiencing daily removal starting Day 1 with flowers that accumulated nectar for one or two days prior to daily removal revealed no discernible effect on the life-of-the-flower nectar production, sugar production and floral longevity. Flowers produce about the same cumulative volume of nectar during the two sexual phases. However, cumulative nectar sugar production is about 4 times higher during the male phase. Nectar standing crop ranged from 4–26.6 µl for Day 1 flowers and 0–8.7 µl for flowers from which nectar was removed the previous day. With daily removal of nectar, 21 of 40 flowers contained no nectar during the last day of the flower's life. All unmanipulated flowers developed fruits (autonomous self-pollination). However, manual self-pollinations and manual cross-pollinations resulted in fruits that weighed significantly more and had significantly more seeds than fruits produced by autonomous self-pollination. Protogyny and herkogamy promote cross-pollination, but delayed autonomous selfing at the end of the flower's life ensures seed set if pollinator-mediated pollination fails.