Reproductive biology of the herkogamous vine Chiococca alba (L.) Hitchc. (Rubiaceae) in the Atlantic Rain Forest, SE Brazil

Abstract

-(Reproductive biology of the herkogamous vine Chiococca alba (L.) Hitchc. (Rubiaceae) in the Atlantic Rain Forest, SE Brazil). The family Rubiaceae comprises a wide spectrum of floral mechanisms and two of them seem to be common in certain groups, e.g., distyly in Rubioidae and styllar pollen in Ixoroidae. These mechanisms include herkogamy, which is interpreted as a strategy that avoids self-pollination. This is the first report on the reproductive biology of Chiococca alba, a species that is widely distributed in America. We studied floral biology and the mating system, which were evaluated through fruit set comparisons after controlled crosses (self-and cross-pollinations and test for apomixis), as well as through the evaluation of pollen tube growth resulting from these controlled crosses. Flowers of C. alba are herkogamous, cream, protandrous and lasted for two days. No measurable nectar was found, despite the presence of a nectary-like structure at the base of the corolla tube. Chiococca alba is a preferentially self-incompatible species, but self-pollination and apomixis also contribute to the natural fruit-set. Its reproductive strategy (herkogamy associated with protandry) is different from that expected for members of Chiococceae tribe (i.e., styllar pollen presentation).Key words -Atlantic Rain Forest, breeding system, Chiococca, floral biology, herkogamy, pollination, Rubiaceae RESUMO -(Biologia reprodutiva da espécie hercogâmica Chiococca alba (L.) Hitchc. (Rubiaceae) na Floresta Tropical Atlântica, SE Brasil). A família Rubiaceae apresenta uma grande variedade de mecanismos florais e dois deles parecem ser comuns em determinados grupos, tais como a distilia em Rubioidae e apresentação de pólen no estilete em Ixoroidae. Estes mecanismos incluem a hercogamia, uma estratégia que parece minimizar as chances de autopolinização. Este é o primeiro estudo acerca da biologia reprodutiva de Chiococca alba, uma espécie de ampla distribuição na América. Foram coletados dados da biologia floral e do sistema reprodutivo, avaliado através da observação de formação de frutos e crescimento de tubos polínicos após cruzamentos controlados. Flores de C. alba são hercogâmicas, protândricas, de cor clara e duram dois dias. Não foi observada a produção mensurável de néctar, apesar da presença de uma estrutura semelhante a um disco nectarífero na base do tubo da corola. C. alba é uma espécie preferencialmente auto-incompatível, no entanto, a autopolinização e a apomixia também contribuem para a produção de frutos em condições naturais. A estratégia reprodutiva observada (protandria e hercogamia) é diferente daquela esperada para a tribo Chiococceae (i.e., apresentação de pólen no estilete).

The Hazardous Level of Heavy Metals in Different Medicinal Plants and Their Decoctions in Water: A Public Health Problem in Brazil

“…In this study, Cr concentration from the plants in the decoction process varied between 0.7 ± 0.4 and 23 ± 0.3 µg/L (Table 8), and the permissible oral daily exposure (PDE) value set by USP is 11,000 µg/day [17]. On the other hand, the concentration of Cu from the plants varies widely between 33 ± 0.4 and 374 ± 0.3 µg/L, and the recommended PDE by the USP is 3000 µg/day.…”

“…C. alba (L.) Hitchc. (Rubiaceae), commonly known in Brazil as "Cainca" or "cipó-cruz," is a tropical and subtropical shrub distributed in some regions of Brazil [17]. Also, Echites peltata is a medicinal plant marketed freely in various regions of Brazil.…”

Contribution to the knowledge of three Indian Spermacoce L. (Rubiaceae) and some preliminary information about their pollination ecology

“…At the time of pollen deposition the stigma lobes are fused so that contact between self-pollen and the receptive surfaces is improbable. Yeo (1993) and Castro et al (2008) suggested that protandry, herkogamy, and self-incompatibility are the primary means of avoiding self-interference in plants with secondary pollen presentation. Ladd (1994) stated the secondary pollen presentation has evolved to increase the efficiency and accuracy of pollen transfer because of the close proximity of pollen to the stigma while Webb & Lloyd (1986) stated that the proximity of pollen and stigma, however, could result in self-interference.…”

“…Ladd (1994) stated the secondary pollen presentation has evolved to increase the efficiency and accuracy of pollen transfer because of the close proximity of pollen to the stigma while Webb & Lloyd (1986) stated that the proximity of pollen and stigma, however, could result in self-interference. Castro et al (2008) suggested that the mechanism of secondary pollen presentation might be an accurate system for pollen transport, but that it may also have its costs.…”