RESUMO
Urban ecosystems could jeopardize the existence of vascular epiphytes (VE) given that their occurrence is linked to phorophyte availability and particular climatic conditions. Despite reports of VE in cities, nothing is known about their demography. A first step in this direction is to describe their population structures (PS). We established the PS of VE present in urban parks in Oaxaca City (Mexico), addressing the following questions: 1) what is their demographic status? and 2) are there differences in the structure of populations growing in native versus exotic phorophytes? During 2021, we censused all the trees in six urban parks, recording their origin (native or exotic), the epiphytic species found on them and the development stages present in each VE population. Overall, five VE species were documented: Tillandsia ionantha, T. makoyana, T. sp., T. schiedeana and T. recurvata (Bromeliaceae); the first three with only one individual and the latter two with 95 and 5,694, respectively. A MANOVA test indicated significant differences in PS between T. recurvata (type I structure, suggesting a growing population) and T. schiedeana (type III structure, suggesting a senile population) (Wilkes' λ= 0.821, F-Radio= 11.96 P<0.001). PS showed no differences related to tree origin. Our results indicate that it is necessary to conduct demographic studies to have a more accurate idea of the current condition of vascular epiphytes in cities. For instance, even though we found five VS species, only one of them seems to have viable populations in Oaxaca city.
Ecossistemas urbanos podem comprometer a existência de epífitas vasculares (EV), dado que sua ocorrência está ligada à disponibilidade de forófitos e condições climáticas particulares. Apesar dos relatos de EV nas cidades, nada se sabe sobre sua demografia. Um primeiro passo nessa direção é descrever suas estruturas populacionais (PS). Estabelecemos o PS dos EV presentes nos parques urbanos da cidade de Oaxaca (Mexico), abordando as seguintes questões: 1) qual é a sua situação demográfica? e 2) existem diferenças na estrutura das populações crescendo em forófitos nativos versus exóticos? Durante o ano de 2021, realizamos o censo de todas as árvores em seis parques urbanos, registrando sua origem (nativa ou exótica), as espécies epífitas encontradas nelas e os estágios de desenvolvimento presentes em cada população de EV. Ao todo, cinco espécies de EV foram documentadas: Tillandsia ionantha, T. makoyana, T. sp, T. recurvata e T. schiedeana; as três primeiras com apenas um indivíduo e as duas últimas com 5.694 e 95, respectivamente. Um teste MANOVA indicou diferenças significativas no PS entre T. recurvata (estrutura tipo I, sugerindo uma população crescente) e T. schiedeana (estrutura tipo III, sugerindo uma população senil) (Wilkes' λ= 0,821, F-Radio= 11,96 e P < 0,001). PS não apresentou diferenças relacionadas à origem da árvore. Os resultados do presente trabalho indicam a necessidade de se realizar estudos demográficos para se ter uma ideia mais precisa da condição atual das epífitas vasculares nas cidades. Embora tenhamos encontrado cinco espécies de VS, apenas uma delas parece ter populações viáveis na cidade de Oaxaca.
Assuntos
Tillandsia/classificação , Cidades , MéxicoRESUMO
We studied C stable isotopic composition (delta(13)C) of bulk leaf tissue and extracted sugars of four epiphytic Tillandsia species to investigate flexibility in the use of crassulacean acid metabolism (CAM) and C(3) photosynthetic pathways. Plants growing in two seasonally dry tropical forest reserves in Mexico that differ in annual precipitation were measured during wet and dry seasons, and among secondary, mature, and wetland forest types within each site. Dry season sugars were more enriched in (13)C than wet season sugars, but there was no seasonal difference in bulk tissues. Bulk tissue delta(13)C differed by species and by forest type, with values from open-canopied wetlands more enriched in (13)C than mature or secondary forest types. The shifts within forest habitat were related to temporal and spatial changes in vapor pressure deficits (VPD). Modeling results estimate a possible 4% increase in the proportional contribution of the C(3) pathway during the wet season, emphasizing that any seasonal or habitat-mediated variation in photosynthetic pathway appears to be quite moderate and within the range of isotopic effects caused by variation in stomatal conductance during assimilation through the C(3) pathway and environmental variation in VPD. C isotopic analysis of sugars together with bulk leaf tissue offers a useful approach for incorporating short- and long-term measurements of C isotope discrimination during photosynthesis.
Assuntos
Metabolismo dos Carboidratos , Carboidratos/análise , Carboidratos/química , Isótopos de Carbono/metabolismo , Ecossistema , Tillandsia/metabolismo , Árvores/fisiologia , México , Fotossíntese/fisiologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Estômatos de Plantas/crescimento & desenvolvimento , Estômatos de Plantas/metabolismo , Estações do Ano , Solubilidade , Tillandsia/classificação , Água/metabolismoRESUMO
Using collection specimens, we measured the density and wing area of trichomes in 37 species of the bromeliad genus Tillandsia, specifically the abaxial proximal, abaxial distal, adaxial proximal and adaxial distal parts of the leaf. The product of the trichome "wing" area by the number of trichomes (means) produced a pure number (T) that was correlated to ecological features. The correlation was positive with respect to arid environments (xeric Tillands) and negative with respect to humid environments (mesic Tillands). Bulbous, and particularly myrmecophytic species and species with tanks, represented particular categories. Other intermediate types were identified based on the T number, totalling five ecological types. In comparison with other systems of ecological typification for Tillands and other Bromeliaceae, the present system offers measurable data whose analysis is reproducible.
Assuntos
Folhas de Planta/anatomia & histologia , Tillandsia/classificação , Especificidade da Espécie , Tillandsia/anatomia & histologiaRESUMO
La recolección reciente de un ejemplar de inflorescencia tri-pinnada motivó la evaluación de los taxones con inflorescencias tri-pinnadas de Tillandsia subgénero Tillandsia para la flora peruana. Se aclara las características de T. extensa, confirmándose su distribución para el noreste del Perú y reconociéndose un ejemplar, previamente considerado como el segundo registro de la especie, como T. platyphylla.
A recent collection of a specimen with three-pinnate inflorescence was the inspiration to evaluate Tillandsia subgenus Tillandsia taxa with three pinnate inflorescences for the Peruvian flora. Tillandsia extensa characteristics are clarified, confirming its distribution for northeastern Peru, and recognizing a specimen, previously considered being the second record for this species, as T. platyphylla.
Assuntos
Flora , Tillandsia/anatomia & histologia , Tillandsia/classificação , Tillandsia/crescimento & desenvolvimentoRESUMO
Using collection specimens, we measured the density and wing area of trichomes in 37 species of the bromeliad genus Tillandsia, specifically the abaxial proximal, abaxial distal, adaxial proximal and adaxial distal parts of the leaf. The product of the trichome "wing" area by the number of trichomes (means) produced a pure number (T) that was correlated to ecological features. The correlation was positive with respect to arid environments (xeric Tillands) and negative with respect to humid environments (mesic Tillands). Bulbous, and particularly myrmecophytic species and species with tanks, represented particular categories. Other intermediate types were identified based on the T number, totalling five ecological types. In comparison with other systems of ecological typification for Tillands and other Bromeliaceae, the present system offers measurable data whose analysis is reproducible.
Medimos el número por milímetro cuadrado y el área del ala (parte móvil) de los tricomas en las partes adaxial próxima y distal, y adaxial próxima y distal, de la hoja de 37 especies de bromelias del género Tillandsia. El producto del área del ala para el número de los tricomas (promedio) produjo un número puro (T). Hallamos que T se correlaciona con las características ecológicas de las tilandsias investigadas. La correlación es positiva con respecto a ambientes áridos (especies xéricas) y negativa con respecto a los ambientes húmedos (especies mésicas). Las especies con bulbo, y particularmente las asociadas con hormigas y especies con de tanque representan categorías particulares. Identificamos otros tipos intermedios, agradando así cinco tipos ecológicos. En comparación con otros sistemas de tipificación ecológica, este sistema ofrece la ventaja de ser reproducible y cuantitativo.