Reproductive success and fruit quality of Ipomoea purpurea (Convolvulaceae) populations at the species southern distribution limit

Abstract

The fruit and seed production of  I. purpurea were estimated with respect to different pollination treatments (autonomous self-, hand self-, and hand cross-pollination treatments) during two reproductive seasons. Seed mass, fruit mass, and seed number per fruit were measured for each fruit and
compared between treatments and seasons to evaluate fruit quality. The results obtained for Argentinean populations confirm that this species is self-compatible and capable of producing fruits by autonomous selfing. Reproductive success of naturally pollinated plants was high (> 50%). A ripened fruit weights 0.1 g and contains 4-6 seeds which represent ca. 60% of the total fruit mass. Fruit and seed traits were not
significantly different between pollination treatments and between years. In addition, fruits and seeds produced by natural pollination were compared between different flower color morphs. No significant differences were detected, with the exception of one morph (pink flowers) which produced fruits with a slight lower number of seeds than the fruits of the other morphs (white or purple flowers). The main flower visitors were different species of Hymenoptera, which can be considered as pollinators. Other flower visitors were recorded but they do not seem to make a significant contribution to transfer pollen.