ABSTRACT
Prosopis laevigata and Mimosa biuncifera are frequently found in arid and semiarid shrublands, but scarce information is available about their influence on plant community structure and soil fertility. We compared plant community structure, diversity and soil nutrients of three semiarid shrubland sites located in Mezquital Valley, Mexico. These sites differ in their dominant species: Site 1 (Bingu) P. laevigata, Site 2 (González) M. biuncifera, and Site 3 (Rincón) with the presence of both legumes. The results showed that the plant community with P. laevigata and M. biuncifera (Site 3) had more cover, taller plants and higher plant diversity than sites with only one legume (Site 1 and Site 2). Soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), phosphorus-Olsen (P) and C mineralization were higher in the soil under the canopy of both legumes than in bare soil. In contrast, soil cation concentrations were lower under the canopy of P. laevigata, but not for M. biuncifera. In addition, the density of arbuscular mycorrhizal fungi spores was higher within the soil under the canopy of M. biuncifera than in the soil under the canopy of P. laevigata. Thus, resource islands (RI) created by P. laevigata increased the amounts of SOC, TN and P when compared with the RI of M. biuncifera. This study provided evidences about the importance of species identity in order to expand the niche availability for the establishment of other plants, and highlights that P. laevigata and M. biuncifera jointly influencing plant colonization within semiarid ecosystems.
Prosopis laevigata y Mimosa biuncifera coexisten en los matorrales semiáridos; sin embargo, se desconoce su influencia sobre la diversidad de la comunidad vegetal y el suelo. Este estudio evaluó el efecto de P. laevigata y M. biuncifera sobre la estructura, diversidad vegetal y nutrimentos del suelo, en tres matorrales del Valle del Mezquital, México. Los sitios difieren en la especie dominante: Sitio 1, P. laevigata; Sitio 2, M. biuncifera y Sitio 3, ambas leguminosas. En cada sitio se recolectó suelo, tanto abajo y fuera del dosel de las leguminosas, además, se realizaron transectos para medir e identificar las plantas arbóreas y arbustivas, se calculó el índice de valor de importancia y la diversidad del matorral. Asimismo, se registró mayor riqueza y diversidad en el Sitio 3 (ICE 29 spp. y H’ 2.7), en comparación con el Sitio 1 (24 spp. y 2.4) y Sitio 2 (26 spp. y 2.1). La materia orgánica y el carbono orgánico del suelo, así como el N total, el P-Olsen y la mineralización de C fueron mayores en el suelo bajo dosel de ambas leguminosas. La abundancia de esporas de hongos micorrizógenos arbusculares fue favorecida por M. biunficera. La influencia de P. laevigata para crear islas más ricas en recursos fue mayor que en M. biunficera, lo anterior sugiere que cada leguminosa modifica de una forma diferente el microambiente, sin embargo, juntas aumentan la disponibilidad de nichos para el establecimiento de otras especies, lo queayuda a comprender el papel de P. laevigata y M. biuncifera sobre la colonización vegetal en ecosistemas semiáridos.
Subject(s)
Biodiversity , Mimosa/physiology , Prosopis/physiology , Soil Microbiology , Soil/chemistry , Desert Climate , Ecosystem , Fungi/classification , Fungi/isolation & purification , Mexico , Mimosa/classification , Prosopis/classification , SeasonsABSTRACT
A necessidade de encontrar novas drogas eficazes no combate microbiano tem aumentado a cada dia e estimulado a busca de novos compostos naturais com atividades biológicas. Neste trabalho, realizaram-se estudo fitoquímico e análises microbiológicas com os extratos etanólicos das espécies (jurema-preta) Mimosa tenuiflora (Wild) Poiret e (jurema-branca) Piptadenia stipulacea (Benth) Ducke, frente a linhagens de bactérias patogênicas. O pó da casca do caule de ambas as espécies foi submetido à avaliação bromatológica e determinados os teores de Matéria Seca, Matéria Mineral, Proteína Bruta, Fibra em Detergente Neutro e Energia Bruta. Os resultados para a prospecção química indicaram a presença de taninos e outros compostos fenólicos, bem como a presença de saponinas em ambos os extratos. Os extratos das duas espécies demonstraram que mais de uma parte das plantas possui atividade antimicrobiana. A composição bromatológica da casca do caule de jurema-preta e jurema-branca apresentou teores diferenciados para as variáveis avaliadas.
The need to find new efficient drugs to combat microbes has increased the search for new natural compounds with biological activities. In this work, phytochemical studies and microbiological analysis were carried out with the ethanol extracts of Mimosa tenuiflora (Wild) Poiret and Piptadenia stipulacea (Benth) Ducke on pathogenic bacteria strains. The bark powders of both species were submitted to bromatologic evaluation and the levels of dry matter, mineral matter, crude protein, neutral detergent fiber (NDF) and crude energy were determined. The results of the chemical search chemical showed the presence of tannins and other phenolic compounds as well as the presence of saponins in both extracts. The microbiologic evaluation of the extracts of both species showed that more than one part of the plants had antimicrobial activity. The bromatologic composition of the bark powder of Mimosa tenuiflora (Wild) Poiret and Piptadenia stipulacea (Benth) Ducke showed different contents for analyzed variables.