Wang,H (reprint author),Chinese Acad Sci,Key Lab Plant Biodivers & Biogeog East Asia,Kunming 650201,Yunnan,Peoples R China.
Orchid species that are food mimics produce fewer fruits than species offering rewards, but few studies have shown the impact of environmental factors (e.g. anthropogenic activity, frost and herbivores) on their reproductive success over several seasons. In this study, we focused on the sole population of the endangered Calanthe yaoshanensis as it secretes no nectar. We investigated its floral biology, fruit set rates and prevailing environmental factors over three seasons (2008-2010). Mechanical self-pollination did not occur in C.yaoshanensis, but hand-selfed and crossed flowers produced equal numbers of fruit. However, seed viability and embryo size were significantly higher in cross-pollinated fruits maximizing embryonic fitness. Large hoverflies (Syrphidae) and Bombus patagiatus (gynes) were the only pollinarium vectors, but they often failed to disperse pollinaria. We interpret the temporary retention of the anther cap over the pollinarium as an adaptation lowering self-pollination. Insect-mediated rates of pollinarium removal were always higher than rates of pollinia deposition on stigmas. Over 3 years, natural rates of pollinarium removal differed significantly, whereas natural rates of fruit set were not significantly different (<22%). Climate, herbivory and anthropogenic collections also inhibited some fruit set and maturation. Both biotic and abiotic factors appear to lower the fecundity of this endangered population.(c) 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 421-433.
1.Chinese Acad Sci, Key Lab Plant Biodivers & Biogeog East Asia, Kunming 650201, Yunnan, Peoples R China 2.Chinese Acad Sci, Kunming Inst Bot, Germplasm Bank Wild Species, Plant Germplasm & Genom Ctr, Kunming 650201, Yunnan, Peoples R China 3.St Louis Univ, Dept Biol, St Louis, MO 63103 USA
Ren,Zong-Xin;Wang,Hong;Bernhardt,Peter;Camilo,Gerardo;Li,De-Zhu.Which food-mimic floral traits and environmental factors influence fecundity in a rare orchid, Calanthe yaoshanensis?,BOTANICAL JOURNAL OF THE LINNEAN SOCIETY,2014,16(21):5808-5811