Ocorrência de auto-incompatibilidade homomórfica em Mitracarpus longicalyx E. B. Souza & M. F. Sales (Rubiaceae - Spermacoceae)

Abstract

-(Occurrence of homomorphic self-incompatibility in Mitracarpus longicalyx E. B. Souza & M. F. Sales (Rubiaceae -Spermacoceae)). The breeding system of Mitracarpus longicalyx was studied from September to December 2004 at Feira de Santana, BA, Brazil. This species is an annual herb found in the "caatinga" of northeastern Brazil, flowering between June and December. The inflorescences are glomerules with ca. 90 flowers. Each flower has a white 4-5 mm long hypocrateriform corolla. The flowers are protandrous with a three days long staminate phase followed by a five days long pistilate phase. No overlapping between phases was observed within a flower, but flowers in different phases appear in the same inflorescence. M. longycalyx is psycophilous species, pollinated by Hemiargus hanno hanno (Stoll, 1790) (Lycaenidae). Hand-pollination tests indicated that M. longicalyx is a self-incompatible, non-agamospermous species, with high fruit set under natural conditions (97.8%) in the studied population; fruit set was also high (82.3%) with hand cross-pollinations but geitonogamous hand pollination gave zero fruit set. Out-crossed pollen tubes reached the ovary within 24h after pollination, while selfed pollen grains failed to germinate or selfed pollen tubes failed to penetrate the stigmatic papillae. The results indicate that M. longicalyx has homomorphic self-incompatibility, possibly of the sporophytic type, in addition to protandry. Homomorphic self-incompatibility is very rare in the Rubiaceae, a family with abundant occurrence of heteromorphic self-incompatibility.Key words -breeding system, Mitracarpus, protandry, Rubiaceae, self-incompatibility RESUMO -(Ocorrência de auto-incompatibilidade homomórfica em Mitracarpus longicalyx E. B. Souza & M. F. Sales (Rubiaceae -Spermacoceae)). O estudo da biologia reprodutiva de Mitracarpus longicalyx E.B. Souza & M.F. Sales foi realizado durante os meses de setembro a dezembro de 2004, em Feira de Santana, BA, Brasil. Esta espécie é uma erva anual ocorrente em áreas de caatinga, florescendo de junho a dezembro. As inflorescências são glomérulos com 90 flores em média, que apresentam corola hipocrateriforme, medindo 4-5 mm de comprimento e coloração branca, sendo visitadas e polinizadas por borboletas da espécie Hemiargus hanno hanno (Stoll, 1790) (Lycaenidae). As flores são protândricas, com duração da fase estaminada de três dias e da fase pistilada de cinco dias. Não ocorre sobreposição das duas fases na mesma flor, mas podem ocorrer flores em diferentes fases na mesma inflorescência. Polinizações experimentais indicaram que M. longicalyx é uma espécie autoincompatível não agamospérmica, com produção natural de frutos elevada (97,8%) na população estudada. A frutificação também foi elevada nas polinizações cruzadas manuais (82,3%), não ocorrendo frutificação nas polinizações manuais geitonogâmicas. Tubos polínicos provenientes de polinizações cruzadas alcançaram o ovário dentro de 24 horas, enquanto que grãos de pólen provenientes de autopolinização não germinaram o...

Phytochemical profile, toxicity and antioxidant activity of Aloysia gratissima (Verbenaceae)

“…In Brazil, its folk name is "erva-santa", popularly named by local communities that use its aqueous extract to which they attribute several therapeutic benefits. In traditional medicine, it is thought to be a remedy to alleviate and help treat symptoms associated with headaches, bronchitis, and nervous system disorders 1 including depression 2 and also to treat digestive system disorders. 3 However, there are no published studies investigating Aloysia gratissima's toxicity while scientific articles about its chemical composition or antioxidant action are scarce, with those available focusing mainly on aqueous extract.…”

Is the pollination biology ofBathysaandSchizocalyxconsistent with their segregation? A first approach for two sympatric species in southeastern Brazil

“…cuspidatus suggests the action of a sporophytic mechanism of self‐incompatibility, as proposed for Coffea canephora (Devreux et al, ). However, as pointed out by Souza et al () for Mitracarpus longicalyx , self‐incompatibility in S . cuspidatus may be gametophytic associated with stigmatic inhibition, as found in other species of Coffea (Lashermes et al, ).…”

“…Its members also have a wide spectrum of pollination agents, mainly diurnal and nocturnal insects of different orders (e.g., Riveros et al, ; Ortiz et al, ; Lasso & Naranjo, ; Teixeira & Machado, ; Consolaro et al, ; Santos et al, ; Ávila & Freitas, ; Xie et al, ), and also hummingbirds (e.g., Sobrevilla et al, ; Ornelas et al, ) and bats (Sazima et al, ). As the angiosperm family with the most heterostylic taxa (Barrett & Richards, ), reproductive studies have focused on species with this trait, and little is known about pollinators and self‐incompatibility systems in homomorphic taxa (Souza et al, ).…”

Pollinators of Richardia grandiflora (Rubiaceae): an Important RuderalSpecies for Bees

“…Among the breeding systems of self-incompatibility known in Rubiaceae, the heteromorphic heterostyly system is the most widely distributed (Souza et al 2007). Information about homomorphic self-incompatibility in Rubiaceae is scarce, and there are few studies such as with Cephalanthus occidentalis (Imbert & Richards 1993), Manettia cordifolia (Consolaro et al 2005), and Mitracarpus longicalyx (Souza et al 2007).…”

“…Information about homomorphic self-incompatibility in Rubiaceae is scarce, and there are few studies such as with Cephalanthus occidentalis (Imbert & Richards 1993), Manettia cordifolia (Consolaro et al 2005), and Mitracarpus longicalyx (Souza et al 2007). This reality can be a consequence of the concentration of studies in reproductive biology on heterostylic species (Souza et al 2007) and not exactly the rarity of the homomorphic selfincompatibility in Rubiaceae. Due to the relevance of this information, self-incompatibility in R. grandiflora needs to be further investigated, conducting controlled hand pollination and microscopic studies, to understand the mechanisms that are involved in this process.…”