Pollen quality limitation in the Iberian critically endangered genus Pseudomisopates (Antirrhinaceae)

Abstract

Pollen limitation occurs when sexual reproduction is decreased due to inadequate pollen receipt. Limitation is usually associated with the quality and the quantity of pollen; still, most studies do not discriminate between the two. We used handpollination experiments and observations of floral visitors to determine the mating system and limitations to seed production of the Spanish endangered species Pseudomisopates rivas-martinezii. We tested for agamospermy, autogamy, obligated autogamy, cross-pollination and supplementation. The response variables considered were fruit set, seed set and viable seed set. Previous studies indicated that (i) the species exhibits extensive clonal growth, (ii) plants flower profusely in summer, (iii) seeds showed to be highly unviable, and (iv) no seedlings were observed in the field. We found that P. rivas-martinezii is predominantly self-incompatible, has an unexpected generalized pollination system considering its occluded corolla, and is limited by qualitative rather than quantitative pollen limitation. These results indicate that, in addition to other presumed environmental factors, the low seed viability of this self-incompatible species is due to pollen quality limitation as a result of reduced mate availability.

Narrow endemics in European mountains: high genetic diversity within the monospecific genus Pseudomisopates (Plantaginaceae) despite isolation since the late Pleistocene

“…Pseudomisopates is a pyrophyte in which germination is strongly stimulated by fire (Amat, ; Amat et al ., ). It has been shown to be self‐incompatible and reproduction is pollen‐limited (Amat et al ., ).…”

“…The species is ecologically linked to the Cytisus oromediterraneus‐ scrubland belt found across the Iberian Central Range, and extends from 1400 to 1990 m a.s.l. (Amat et al ., , ). Pseudomisopates is a pyrophyte in which germination is strongly stimulated by fire (Amat, ; Amat et al ., ).…”

“…Given that distribution models based on a low number of presence records may be problematic (Pearson et al ., ), we modelled the distribution of the co‐occurring shrub species Cytisus oromediterraneus instead. This species characterizes the habitat of Pseudomisopates (Amat et al ., ), but it is more widely distributed in mountains of the northern half of Iberia and southern France (Cubas et al ., ). We retrieved 368 point localities of C. oromediterraneus from the Spanish node of the Global Biodiversity Information Facility (GBIF, http://www.gbif.es/; Otegui et al ., ).…”

Local shifts in floral biotic interactions in habitat edges and their effect on quantity and quality of plant offspring

“…Pollen limitation also involves qualitative components of plant reproduction (i.e. offspring viability), which depend on the features of transferred pollen ( Wilcock and Neiland 2002 ; Amat et al 2011 ; Arceo-Gomez and Ashman 2014 ). The interplay between the structuring of plant populations and insect assemblages can affect the quality of pollen delivery (i.e.…”

“…In the first case, PL originates from insufficient pollen transfer, which is typically due to the scarcity of pollinators ( Ashman et al 2004 ). Instead, qualitative PL is due to a poor quality of the pollen admixture deposited onto stigmas ( Amat et al 2011 ; Arceo-Gomez and Ashman 2014 ). Variations in abundance, composition and behaviour of pollinating fauna may represent a primary source of both quantitative and qualitative PL ( Gómez et al 2010 ).…”