Comparative floral nectar attributes in four <i>Swertia</i> species (Gentianaceae)

Abstract

Aims: Floral nectar secretions at interspecific and intraspecific levels, as well as the variation among different flowers within a plant, influence pollinator attraction. By impacting pollinator visitation patterns, these factors consequently influence pollination effectiveness and plant reproductive success. However, our understanding of the variability in floral nectar production is limited by a lack of quantitative measurements. Methods: In this study, we selected four sympatric species within the genus Swertia (Gentianaceae), Swertia bimaculata, S. cincta, S. kouitchensis and S. punicea, to study variations in floral nectar attributes. We compared volume, sugar concentration and sugar content (weight) for flowers under two treatments: (1) flowers bagged for 24 hours and (2) freshly opened flowers in natural field conditions. We examined differences among neighboring flowers to test floral nectar variations across and within individual plants. Results: We found that floral nectar attributes were significantly different among the studied species. Except for sugar concentration in S. bimaculata and S. kouitchensis, all nectar attributes differed between treatments. Sugar concentration •研究报告•