Effect of mycorrhizae on seedlings of six endemic Mimosa L. species (Leguminosae–Mimosoideae) from the semi-arid Tehuacán–Cuicatlán Valley, Mexico

Abstract

Mimosa is an important genus of legumes in arid and semi-arid ecosystems of the world, but scarce information is available about its interaction with microbial symbionts. In Mexico, there are no reports on the responsive of endemic Mimosa species to arbuscular mycorrhizal (AM) fungal colonization. In this study, the AM association with seedlings of six endemic Mimosa species, M. adenantheroides, M. calcicola, M. lacerata, M. luisana, M. polyantha and M. texana var. filipes, is reported. Field conditions were simulated in the greenhouse. Seeds were collected from plants and soil from the localities where the species occur within the semi-arid Tehuacán-Cuicatlán Valley, Mexico. Four treatments were applied: (1) control, (2) benomyl, (3) phosphorus, and (4) benomyl plus phosphorus. Mycorrhizal seedlings of five species, M. adenantheroides, M. lacerata, M. luisana, M. polyantha and M. texana var. filipes, showed a higher shoot and total dry weight than non-mycorrhizal seedlings. The only species that did not show any difference between mycorrhizal and non-mycorrhizal seedling performance was M. calcicola. M. luisana, M. polyantha and M. texana var. filipes had a higher root/shoot ratio; in general, benomyl treatments promoted seedling biomass allocation to the root, while control, phosphorus and benomyl plus phosphorus treatments decrease root/shoot ratio. Shoot P content was significantly higher in mycorrhizal than in non-mycorrhizal plants, although no significant differences were found for M. adenantheroides in all treatments. Benomyl and benomyl plus phosphorus treatments reduced AM colonization in all the species under study. Benomyl significantly reduced the number of N 2 -fixing root nodules, while the phosphorus treatment generally stimulated nodulation. The species M. lacerata, M. luisana, M. polyantha and M. texana var. filipes had a high mycorrhizal dependency index indicating that plant growth was strongly increased by arbuscular mycorrhiza activity. Our results indicate that the response of all Mimosa species to mycorrhization was highly variable. To our knowledge, this is the first report about the effect of AM fungi and phosphorus on Mimosa species, which may be useful in biodiversity and soil conservation programs.

<i>Prosopis laevigata</i> and <i>Mimosa biuncifera</i> (Leguminosae), jointly influence plant diversity and soil fertility of a Mexican semiarid ecosystem.

“…AM fungi may be advantageous to desert plants, when P is practically insoluble, and its diffusion in the soil is further decreased by low soil moisture (Tarafdar & Panwar 2008). Furthermore, P availability under the canopy of both legumes may also be favored by a low soil Ca and Mg concentration, and a slightly acid pH, which agrees with a higher AM fungal spore abundance in the soil under the canopies of both legumes (Camargo-Ricalde et al 2010b). Smith & Read (2008) indicate that the plant-root colonization by AM fungi decreases when P availability is high in the soil, increasing AM fungal spore production.…”

“…These species improve fertility and create resource islands, due to that modify of the micro-environmental conditions and function as reservoirs of soil nutrients, fungi spores and microorganisms under their canopies (Reynolds et al 1999, Camargo-Ricalde & Dhillion 2003, González-Ruiz et al 2008. For instance, arbuscular mycorrhizal fungi are critical to plant establishment, because they improve water and nutrients status of the host plant growing in arid regions (Tarafdar & Panwar 2008, Camargo-Ricalde et al 2010b. Even so, the effect of Prosopis and Mimosa species has been documented for each single species, without elucidating the interactions that could take place among them and with other plant species within the plant community.…”

Endemic Mimosa species from Mexico prefer alphaproteobacterial rhizobial symbionts

“…overwhelmingly prefer to nodulate with Burkholderia rather than Cupriavidus or Rhizobium , (Elliott et al ., ; Melkonian et al ., ), but the predominance of Burkholderia can be overcome at higher N concentrations, which demonstrates that soil N‐content is an important factor in Mimosa symbiont selection (Elliott et al ., ). Furthermore, soils in central Brazil are generally acid (many are less than pH 5.0; dos Reis Junior et al ., ), which would favour the acid‐tolerant genus Burkholderia (Garau et al ., ; Stopnisek et al ., ), whereas those from central Mexico are either weakly acidic, neutral or slightly alkaline (Camargo‐Ricalde et al ., ; this study), which would favour most species of Rhizobium , and also Cupriavidus (Klonowska et al ., ; Liu et al ., ; Mishra et al ., ; Gehlot et al ., ). Further studies using soils and seeds from both Brazil and Mexico could help to determine if (and what) soil characteristics are factors in the selection of symbionts by Mimosa spp.…”

Forestry insularity effect of four Mimosa L. species (Leguminosae-Mimosoideae) on soil nutrients of a Mexican semiarid ecosystem

“…However, interspecific differences were not observed in Nt, because Mimosa species may be N 2 -fixing species, which increases the N circulation in a similar way among species. Camargo-Ricalde et al (2010) reported from 4 to 25 N 2 -fixing nodules in all four species here studied. Nevertheless, Pi varied the most across species due to differences in P content in tissues or to the level of mycorrhizal association among species .…”