title: Mixed pollen load and late-acting self-incompatibility flexibility in Adenocalymma peregrinum (Miers) L.G. Lohmann (Bignonieae: Bignoniaceae).
abstract: Mixed cross and self-pollen load on the stigma (mixed pollination) of species with late-acting self-incompatibility system (LSI) can lead to self-fertilized seed production. This "cryptic self-fertility" may allow selfed seedling development in species otherwise largely self-sterile. Our aims were to check if mixed pollinations would lead to fruit set in LSI Adenocalymma peregrinum, and test for evidence of early-acting inbreeding depression in putative selfed seeds from mixed pollinations. Experimental pollinations were carried out in a natural population. Fruit and seed set from self-, cross and mixed pollinations were analysed. Further germination tests were carried out for the seeds obtained from treatments. Our results confirm self-incompatibility, and fruit set from cross-pollinations was three-fold that from mixed pollinations. This low fruit set in mixed pollinations is most likely due to a greater number of self- than cross-fertilized ovules, which promotes LSI action and pistil abortion. Likewise, higher percentage of empty seeds in surviving fruits from mixed pollinations compared with cross-pollinations is probably due to ovule discounting caused by self-fertilization. Moreover, germinability of seeds with developed embryos was lower in fruits from mixed than from cross-pollinations, and the non-viable seeds from mixed pollinations showed one-third of the mass of those from cross-pollinations. The great number of empty seeds, lower germinability, lower mass of non-viable seeds, and higher variation in seed mass distribution in mixed pollinations, strongly suggests early-acing inbreeding depression in putative selfed seeds. In this sense, LSI and inbreeding depression acting together probably constrain self-fertilized seedling establishment in A. peregrinum.
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: M O
authors.initials: MO
authors.lastname: Duarte
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Mendes-Rodrigues
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: M F
authors.initials: MF
authors.lastname: Alves
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: P E
authors.identifier: http://orcid.org/0000-0002-6162-8702
authors.initials: PE
authors.lastname: Oliveira
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
authors.forename: D S
authors.initials: DS
authors.lastname: Sampaio
mesh_terms: D029402:Bignoniaceae / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018533:Biomass; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018525:Germination; D000071422:Inbreeding Depression; D056771:Ovule / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D011058:Pollen / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D054817:Pollination; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D057945:Self-Fertilization; D060436:Self-Incompatibility in Flowering Plants
keywords: Adenocalymma peregrinum (= Memora peregrina); cryptic self-fertility; germinability; inbreeding depression; self-fertilisation