Size-dependent allocation of biomass to ancillary versus flowers of the inflorescences of the epiphyte Tillandsia stricta Soland (Bromeliaceae)

Abstract

RESUMO -(Influência do tamanho do corpo na alocação de biomassa em estruturas de suporte e flores da bromélia epífita Tillandsia stricta Soland. (Bromeliaceae)). A quantidade de recursos investidos na reprodução sexuada em geral é positivamente correlacionada à quantidade dos mesmos recursos investidos no corpo vegetativo da planta; porém nem sempre de forma proporcional. A proporção dos recursos da planta alocados na reprodução sexuada pode aumentar, diminuir ou se manter constante ao longo do aumento do tamanho do corpo vegetativo. Embora compreendendo milhares de espécies, as epífitas são pouco conhecidas quanto ao padrão de alocação de recursos na reprodução sexuada. Neste estudo é descrita a variação da alocação de recursos na reprodução sexuada da bromélia epífita Tillandsia stricta Soland conforme diferentes tamanhos de corpo vegetativo. O objetivo é avaliar como tal alocação se dá para a inflorescência total à medida que seu corpo vegetativo cresce, bem como quantificar a participação das estruturas de suporte da inflorescência nesta alocação. Com o aumento do corpo vegetativo, a alocação de biomassa na inflorescência como um todo reduziu de 37% para 12%. Entretanto, especificamente para as estruturas de suporte e flores que constituem tal inflorescência, a redução na alocação de biomassa foi de 30% para 9%, nas estruturas de suporte, e de 10% para 3% nas flores. Tanto a área foliar total quanto a área por folha, usadas aqui como indicadoras de forrageamento, também aumentaram com o aumento do tamanho do corpo vegetativo. Tais resultados são discutidos quanto à capacidade de T. stricta de se reproduzir sexuadamente sob as condições heterogêneas da copa das árvores. Palavras-chave: alocação, alometria, Bromeliaceae, estruturas reprodutivas de suporte, TillandsiaABSTRACT -(Size-dependent allocation of biomass to ancillary versus flowers of the inflorescences of the epiphyte Tillandsia stricta Soland (Bromeliaceae)). The amount of resources invested in reproduction is closely correlated to plant size. However, the increase in reproductive investment is not always proportional to the increase in vegetative growth, as the proportion of plant resources allocated to reproduction can increase, decrease or be maintained along different plant sizes. Although comprising thousand of species, epiphytes are poorly studied in relation to reproductive allocation (RA). We describe the variation in the RA of the epiphytic bromeliad Tillandsia stricta Soland with increasing plant sizes. Our goal is not only to evaluate the RA of the whole inflorescence but also quantify the contribution of ancillary structures in the final RA of this plant species. With increasing sizes of T. stricta the reproductive allocation of biomass to the whole inflorescence decreased significantly along plant sizes from 37% to 12%. Reproductive allocation to ancillary and to flowers decreased respectively from 30% to 9% and 10% to 3%. As leaves are the main source of water and nutrients absorption in atmospheric Tillandsia, the total leaf area and ...

Effect of rosette size, clonality and spatial distribution on the reproduction of Vriesea carinata (Bromeliaceae) in the Atlantic Forest of Paraná, southern Brazil

“…Th e reproductive eff ort in V. carinata diff ers from what has been reported for other species, because fl ower production is frequently correlated with plant size, which usually increases with increased resource availability (Ågren et al 2008;Dauber et al 2010). In bromeliads, sexual reproduction tends to increase with an increase in plant size (Benzing 1981;Hietz et al 2002;Mondragón et al 2004;Mantovani & Iglesias 2009). For V. carinata, factors such as the clonality discussed below might be causing an increase in competition for resources and limiting the amount invested in fl ower production, thereby uncoupling the eff ect of rosette size on reproductive eff ort.…”

“…Th e amount of resources invested in reproduction is closely correlated with plant size and biomass, such that bigger/heavier plants invest more in fl owering than smaller plants (Aarssen & Taylor 1992). For bromeliads, the amount of resources invested in reproductive structures is also correlated with the size of the plant, but not always proportionally (Mantovani & Iglesias 2009).…”

Morphological Phylogenetic Analysis of Two Early-Diverging Genera of Bromelioideae (Bromeliaceae)

“…The environments of the Cerrado (Ratter et al 1997) and restinga (Mantovani & Iglesias 2001, 2008 are notorious for their oligotrophic and rapidly draining soils. The little information available about the cost of producing inflorescences in bromeliads indicates that more biomass is allocated to pedunculate inflorescences (Benzing 2000;Mantovani & Iglesias 2009 inflorescence is potentially much smaller than that in a peduncular inflorescence (Benzing & Ott 1981).…”

Reproductive allocation in plants: a reappraisal of the currency issue

“…None of these combinations is optimal as all of them yield biased estimates of RA to some extent (Bazzaz et al 2000). In particular, RA estimates at the flowering peak miss allocation to seeds and only estimate initial, rather than total, allocation to reproduction (Lloyd and Bawa 1984), and RA estimates in terms of seeds can miss up to 70% of resources allocated to reproduction (van Andel and Vera 1977, Hansen et al 1992, Mantovani and Iglesias 2009). Nevertheless, sequential harvest of shed vegetative and reproductive structures is very time consuming in most plant species and has been barely implemented in RA studies.…”