Pollination ecology of the rare desert species Eremosparton songoricum (Fabaceae)

Abstract

The pollination ecology of Eremosparton songoricum (Litv.) Vass., a rare desert species endemic to central Asia, was examined by a series of observational studies and manipulative experiments in two natural populations during [2007][2008]. Results showed that the duration of flowering lasted 21 and 23 days, respectively, in Populations A and B from late May to late June in 2008. Anthesis of a single flower often lasted for 3 days. However, if pollinators were excluded, both the anthesis and stigma receptivity lasted 2 days longer. Mating-system experiment showed that E. songoricum was self-compatible and pollination success relied on pollinators. Fruit set after bagging without emasculation was 0.02 AE 0.01%. This suggested that spontaneous autogamy rarely happened. E. songoricum primarily relies on a combination of large floral display, secretion of nectar and a yellow 'nectar guide' on the standard to further attract pollinators, which may be the result of adaptation to a habitat with unreliable access to pollinators. A single flower produced~0.18 mL and 0.50 mL of nectar during 2 days in Populations A and B, respectively. The peak secretion occurred at 1300-1500 hours, which overlapped with the climax of visitation of the effective pollinators at 1300-1400 hours. There were four effective pollinators in both populations, namely Colletes popovi Nosk., Megachile terminate Morawitz, Coelioxys sp. and Bembix planifrons F.Mor. The most frequent one, Colletes popovi Nosk., was observed pollinating many flowers of the same individual plant (65.8 AE 1.1%) in Population A, suggesting that geitonogamous self-pollination is unavoidable. Inbreeding depression played a role during the period from fertilisation to fruit maturation.

Effects of sand burial, soil water content and distribution pattern of seeds in sand on seed germination and seedling survival of Eremosparton songoricum (Fabaceae), a rare species inhabiting the moving sand dunes of the Gurbantunggut Desert of China

“…5 Percentage germination and quiescence of scarified seeds (a) and percentage seedling emergence (b) (mean ± SE) of Eremosparton songoricum at different burial depths. Bars with the same letters are not significantly different at P<0.05 according to the LSD multiple comparison test understand the biological and ecological characteristics of this sand dune species for its conservation (Zhang et al 2008;Shi et al 2010). Our controlled experiments and 5-year field investigations indicated that the low seedling recruitment from sexual reproduction is a limiting factor for the regeneration of this species.…”

Effects of Artificial Sand Fixing on Community Characteristics of a Rare Desert Shrub

“…Seed germination rate in the wild is <3%, and seedling establishment rate is <0.1% (e.g., Shi et al. ; Zhang et al. , ).…”

“…Many studies have explored mechanisms of its extirpation and success of its conservation measures (e.g., Shi et al. ; Liu et al. ; Zhang et al.…”

“…Although an individual produces 100-3000 flowers, E. songoricum has low fruit (<16%) and seed set (<20%). Seed germination rate in the wild is <3%, and seedling establishment rate is <0.1% (e.g., Shi et al 2010;Zhang et al 2011aZhang et al , 2011b. Thus, sexual reproduction by E. songoricum is largely ineffective (Liu et al 2011;Zhang et al 2011b).…”

Pollination and breeding system in Adesmia bijuga Phil. (Fabaceae), a critically endangered species in Central Chile

“…For example, in very variable pollination environments, such as the Atacama Desert, the mixed mating system keeps the population of A. argyrophylla alive (González & Pérez 2010). Numerous studies demonstrated a mixed mating system in species with reduced habitat which probably helps to explain how the species are able to survive over time in small and isolated populations (Hill et al 2008, Gargano et al 2009, Shi et al 2010, Powell et al 2011. In this context, selfing ability and autogamous capacity provide reproductive assurance, producing enable seed production when pollinators or mates are scarce or unavailable, and outcross pollen is insufficient for full fertilization of ovules.…”