Reproductive system of Eriocnema fulva Naudin (Melastomataceae), an endemic species of Minas Gerais state, SE Brazil

Abstract

Eriocnema fulva Naudin is a perennial herb, endemic to Minas Gerais state, SE Brazil, found on humid, shaded rocky riverbanks in montane semideciduous seasonal forests. The species is threatened, but information regarding its biology is still lacking, although such information is fundamental to any management plan. We aimed to evaluate the reproductive system of Eriocnema fulva in the Jambreiro Forest (19° 58'-59' S and 43° 55'-52' W, 800-1100 m altitude), municipality of Nova Lima, by experiments carried out in 1997 and 1998. The flowers are white, and flowering is of the steady state type, occurring once a year from November to December. Anthers are poricidal, and pollen is the only resource for visitors. The chromosome number is n = 17 during meiosis. The species is self-compatible, but does not produce fruits by spontaneous self-pollination or agamospermy; it requires pollen vectors and buzz pollination in order to produce fruits. Cross-pollination is the main reproductive strategy of E. fulva, and is accentuated by the small number of flowers (one or two in each plant) opened per day. Although the population studied was shaded by forest canopy, the seeds needed light to germinate. Germination ratio was lower in germination cabinet on filter paper (14% after 30 days) than in greenhouse on soil brought from the forest (47% after 25 days). Although the fruit is a capsule and the seeds are small, dispersion (anemochory or hydrochory) does not seem to occur at long distance, as it is the case for other Melastomataceae species with similar syndrome.Keywords: buzz pollination, chromosome number, reproduction system, self-compatible. Sistema de reprodução de Eriocnema fulva Naudin (Melastomataceae), uma espécie endêmica do estado de Minas Gerais, sudeste do Brasil ResumoEriocnema fulva Naudin é uma planta herbácea, perene, endêmica no estado de Minas Gerais, sendo encontrada em paredões rochosos úmidos, ao longo de riachos sombreados pela Floresta Estacional Semidecídua Montana. A espécie é ameaçada de extinção e não existem informações sobre a sua biologia, embora sejam fundamentais para um plano de manejo. Com o objetivo de avaliar o sistema de reprodução, foram feitos experimentos em 1997 e 1998 em uma população na Mata do Jambreiro (19° 58'-59' S e 43° 55'-52' W, 800-1100 m de altitude), no município de Nova Lima. As flores são brancas e a floração é do tipo steady state, ocorrendo uma vez ao ano durante novembro e dezembro. As anteras são poricidas e o pólen é a única recompensa para os visitantes. O número cromossômico encontrado na meiose foi n = 17. A espécie é autocompatível, não produz frutos por autopolinização espontânea nem por agamospermia, mas requer obrigatoriamente vetores de pólen e polinização vibrátil. A polinização cruzada é a principal estratégia reprodutiva de Eriocnema fulva, sendo acentuada devido ao pequeno número de flores abertas por dia, apenas uma ou duas em cada planta. Embora as populações estejam localizadas em ambientes sombreados e úmidos, as sementes precisam de luz para ...

Reproductive biology and species geographical distribution in the Melastomataceae: a survey based on New World taxa

“…If this relationship between breeding system and geographic distribution applies to the family as a whole, one would anticipate that the species of Melastomataceae with restricted distributions are likely to be sexual species, dependent on pollination for their reproductive success. However, for the moment, there are only isolated studies on the reproductive biology of these endemic species (Andrade et al, 2007) to corroborate this hypothesis.…”

Crepuscular pollination and reproductive ecology of Trembleya laniflora (Melastomataceae), an endemic species in mountain rupestrian grasslands

“…The absence of apomixis may be associated with the endemism and restricted occurrence of T. laniflora on rocky outcrops of campo rupestre in Minas Gerais (Martins, 1997;Santos et al, 2012). The relationship between the reproductive system of Melastomataceae and the geographic distribution of the species is a topic already described in the literature (Goldenberg and Sherpherd, 1998;Andrade et al, 2007;Santos et al, 2012). In general, apomictic species present a wider geographic distribution than those dependent on sexual reproduction, and the latter are frequently endemic or have restricted distribution (Goldenberg and Sherpherd, 1998;Santos et al, 2012).…”

Constant flower damage caused by a common stingless bee puts survival of a threatened buzz-pollinated species at risk

“…The pistil has a style somewhat longer than the stamens with a small and poorly delimited stigma. The species is self-compatible but does not produce fruits by spontaneous self-pollination (Andrade et al 2007a). Fruit set after crosspollination was about 3-fold when compared to geitonogamous pollination in that population, and the plants suffered pollinator limitation.…”

“…There are records of only four populations, all with distribution restricted to rocky cliffs close to small water bodies in the Quadrilátero Ferrífero (Iron Quadrangle) (Andrade 2009), a region in southeast Brazil under heavy anthropogenic impact derived from iron ore mining (Jacobi and do Carmo 2008;Jacobi et al 2011). Studies on the floral biology of E. fulva have detected frequent damage to its flowers (Andrade et al 2007a).…”