Chromosome Studies in Bignonieae (Bignoniaceae): The First Record of Polyploidy in Anemopaegma

Abstract

Summary Anemopaegma (Bignonieae, Bignoniaceae) includes 45 species distributed from Mexico to Northeastern Argentina. The genus is monophyletic and well supported by morphological and molecular characters. However, the delimitation of species within Anemopaegma is complex. In this study, we determined chromosome numbers and interphase nuclei structure for 5 shrubby species of Anemopaegma, 3 of which belong to the Anemopaegma arvense species complex. While most shrubby species analyzed were polyploids (2nϭ4xϭ80), polyploidy was not encountered among the climbing members of the genus. Furthermore, interphase nuclei was shown to vary among species. In particular, A. album was the only species that presented semi-reticulate interphase nuclei, while A. glaucum and A. scabriusculum presented areticulate nuclei. Anemopaegma acutifolium and A. arvense, on the other hand, presented an interphase nuclei structure that was intermediate between the areticulate and semi-reticulate types. Overall, our findings suggest that ploidy level may have had an important role in the diversification of the Neotropical genus Anemopaegma.

Mating in the pseudogamic apomicticAnemopaegma acutifoliumDC: another case of pseudo‐self‐compatibility inBignoniaceae?

“…The occurrence of polyploidy and polyembryony in other species of the genus Anemopaegma of probable hybrid origin (Sampaio ; Firetti‐Leggieri et al . ) suggest the existence of an agamic polyploid complex in this group, as postulated for some species of Handroanthus (Piazzano ; Costa et al . ; Bittencourt & Semir ; Bittencourt & Moraes ).…”

“…Moreover, the possibility that this delay is caused by inbreeding depression effects is weakened because the occurrence of allopolyploidy in Anemopaegma species (Firetti‐Leggieri et al . ) can reduce these effects (Barringer ; Husband et al . ) and allows a sexual embryo and endosperm to develop normally in self‐pollinated pistils.…”

“…But the occurrence of polyploid (Firetti‐Leggieri et al . ), polyembryonic and sporophytic apomictic (Sampaio ) species in a complex of putative hybrid origin (Gentry ; Firetti‐Leggieri et al . ), suggests that self‐fertility may occur in these species as in the other apomictic Bignoniaceae (Bittencourt & Moraes ).…”

“…), polyembryonic and sporophytic apomictic (Sampaio ) species in a complex of putative hybrid origin (Gentry ; Firetti‐Leggieri et al . ), suggests that self‐fertility may occur in these species as in the other apomictic Bignoniaceae (Bittencourt & Moraes ). In the polyploidy, sporophytic apomictic Anemopaegma acutifolium DC, no endosperm development is observed for unpollinated pistils, indicating obligate pseudogamy for seed and fruit set (Sampaio ).…”

“…Anemopaegma is a genus of vines and shrubs with only selfincompatible species reported so far (Correia et al 2006;Carvalho et al 2007). But the occurrence of polyploid (Firetti-Leggieri et al 2011), polyembryonic and sporophytic apomictic (Sampaio 2010) species in a complex of putative hybrid origin (Gentry 1973;Firetti-Leggieri et al 2011), suggests that self-fertility may occur in these species as in the other apomictic Bignoniaceae (Bittencourt & Moraes 2010). In the polyploidy, sporophytic apomictic Anemopaegma acutifolium DC, no endosperm development is observed for unpollinated pistils, indicating obligate pseudogamy for seed and fruit set (Sampaio 2010).…”