Do breeding system and pollen limitation vary with altitude in the widespread herb, Cineraria erodioides (Asteraceae)?

• Published in: South African journal of botany 2019-03, Vol.121, p.377-385
• Main Authors: Black, H.N., Harrison, J.d.G., Cron, G.V.
• Format: Article
• Language: English
• Subjects: Alpine plant breeding systems; Cineraria erodioides; Drakensberg Alpine Centre; Pollen limitation; Self-pollination
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/j.sajb.2018.11.027

Alpine plant species may experience pollen limitation due to low availability of pollinators at higher altitudes, and therefore may be under selection for autonomous self-pollination to ensure reproductive success. Little is known about the reproduction of plant species at high altitudes in southern Africa and whether absence of pollinators influences their breeding system. Two pollination treatments (pollinator exclusion and pollen supplementation) were carried out on Cineraria erodioides (Asteraceae) and compared to natural pollination, at three altitudes in the subalpine (/upper montane) zone along Sani Pass in the southern Drakensberg of South Africa. Our results indicate that C. erodiodes is not able to autonomously self-pollinate, but requires a vector to effect cross-pollination. It may be self-incompatible, but further work is needed to confirm this. Limited pollen supplementation did not significantly improve fruit/seed set at the three altitudes tested (2275, 2637 and 2675 m above sea level). Preliminary use of fluorescent powders suggested that pollen transfer occurs over a range of distances, which may reflect the kinds of insects observed visiting C. erodioides – mainly Coleoptera (beetles) and Diptera (flies), and also likely by wind. •The breeding system of Cineraria erodioides did not vary at three different altitudes in the southern Drakensberg, South Africa.•Cineraria erodioides is not able to autonomously self-pollinate and may be self-incompatible.•Dispersal distances for simulated pollen (paint powder) may reflect ranges of pollinators at high altitude (Diptera, Coleoptera) and/or wind.