Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga

Abstract

-(Reproductive phenology, floral biology and pollination of Allamanda blanchetii, an Apocynaceae endemic of the Caatinga). The reproductive phenology, floral biology, pollination mechanism and breeding system of Allamanda blanchetii A.DC. were studied in natural populations in the Almas Farm, Paraíba, Brazil. Allamanda blanchetii is a shrubby species, endemic of the Caatinga, flowering from February to July, with peak in March-April. The fruiting followed the flowering and continued until September. The tubular flowers are pink, their strong herkogamy preventing self pollination. The pollen grains are deposited in the upper side of the style head (non-receptive region), still in the pre anthesis phase (dehiscent anther), characterizing a secondary pollen presentation. The flowers produce an average of 36.6 µL of nectar, that is the only resource to the floral visitors. Allamanda blanchetii is self incompatible and the results suggest a late-acting self-incompatibility mechanism. The floral attributes are compatible with the melittophilous and psychophilous syndromes. In fact, the observed pollinators were the bee Eulaema nigrita Lepeletier, as main pollinator, and four species of butterflies, which act as secondary pollinators. The occurrence of strong herkogamy, secondary pollen presentation and self-incompatibility mechanism indicates high degree of specialization of pollination and breeding systems of A. blanchetii.Key words -herkogamy, secondary pollen presentation, self incompatibility RESUMO -(Fenologia reprodutiva, biologia floral e polinização de Allamanda blanchetii, uma Apocynaceae endêmica da Caatinga). A fenologia reprodutiva, a biologia floral, o mecanismo de polinização e o sistema reprodutivo de Allamanda blanchetii A.DC. foram analisados em populações naturais na Fazenda Almas, Paraíba, Brasil. Allamanda blanchetii é uma espécie arbustiva, endêmica da Caatinga, com floração de fevereiro a julho e pico nos meses de março e abril. A frutificação acompanhou a floração e estendeu-se até o mês de setembro. As flores são tubulares e de coloração rosa, cuja forte hercogamia evita a autopolinização. O pólen é depositado na parte superior da cabeça do estilete (região não receptiva), ainda na fase de botão em pré antese (anteras deiscentes), caracterizando a apresentação secundária de pólen. As flores produzem uma média de 36,6 µL de néctar, o qual é o único recurso para os visitantes florais. Allamanda blanchetii é auto-incompatível e os resultados sugerem mecanismo de incompatibilidade de ação tardia. Seus atributos florais estão relacionados com as síndromes de melitofilia e psicofilia e, de fato, os polinizadores registrados foram a abelha Eulaema nigrita Lepeletier como principal polinizador e quatro espécies de borboletas que atuam como polinizadores secundários. A ocorrência de forte hercogamia, apresentação secundária de pólen e mecanismo de auto-incompatibilidade indicam o elevado grau de especialização dos sistemas de polinização e reprodução de A. blanchetii.Palavras-chave -apresentaçã...

Phenological study of populations of Cnidoscolus quercifolius in the Western Seridó, Paraiba state, Brazil

“…The highest peaks of flowering and fruiting in these plants were observed during the rainy season, with flowering closely following the period of leaf flushing and leaf blade expansion. Fruiting, on the other hand, continued for a longer period of time, extending into the phenophase of leaf fall, similar to the results reported by Lima (2007); Amorim et al (2009), and Araújo et al (2011), in other plant communities in the caatinga a determinant factor in plant reproduction in tropical regions, especially in tropical dry forests (Griz & Machado 2001). The phenophases of flowering and fruiting were observed to have annual patterns in C. quercifolius in this study and for the period in which it developed.…”

“…Phenological research projects at the community and species levels in the semiarid tropics have contributed greatly to our understanding of the adaptive aspects of the plants occupying these complex biomes, characterized by climatic extremes and high degrees of endemism (Pereira et al 1989;Barbosa et al 1989Barbosa et al , 2003Vogel & Machado 1991;Locatelli & Machado 1999a,b;Quirino & Machado 2001;Machado et al 1997Machado et al , 2002Santos et al 2005;Quirino 2006;Lima 2007;Amorim et al 2009;Guedes et al 2009;Araújo et al 2011;Sobrinho et al 2013).…”

Towards a unified terminology for angiosperm reproductive systems

“…The LSI is still poor understood in angiosperms, found in species of families and genera with taxonomically close relationships (Gibbs 2014). Several families present species with late-acting self-incompatibility, such as Apocynaceae (Araujo et al 2011), Bignoniaceae (Bittencourt Júnior 2017), Fabaceae (Borges et al 2008) and Malvaceae (Souza & Venturieri 2010).…”

High specialisation in the pollination system of Mandevilla tenuifolia (J.C. Mikan) Woodson (Apocynaceae) drives the effectiveness of butterflies as pollinators

“…) and Allamanda blanchetii L. (Araújo et al . ), but only in Apocynum sibiricum L. (Waddington ) were they reported as the main pollen vector. For the genus Mandevilla , Linhart & Feinsinger () observed butterflies visiting flowers of M. hirsuta , but reported that they collected only small amounts of pollen and that hummingbirds were the main pollinator of M. hirsuta .…”