Establishment of catclaw plants (Mimosa biuncifera Benth.) inoculated with arbuscular mycorrhizal fungi in greenhouse and field drought conditions

Abstract

More than half of Mexican territory is dominated by arid or semi-arid ecosystems. These environments are normally deteriorated by man-induced over-grazing by sheep and goats and the mainly vegetation types are xeric shrublands where thorny plant species are widespread, like catclaw ( Mimosa biuncifera Benth., Fabaceae), wich is a nurse plant that promotes plant succession. In this view, the objective of this work was to determine the effect of inoculation with native arbuscular mycorrhizal fungi (AMF) on catclaw seedlings, in order to evaluate plant establishment and their growth under a dry treatment, both in greenhouse and field conditions. Initial question was if the mycorrhization of catclaw increases in a significative way the survival of plant individuals under field conditions. For this, catclaw plants were grown in a greenhouse in Mexico City, with a design consisting of two pot irrigation treatments, wet (W) and dry (D), and two soil treatments: with and without AMF inoculum (M+, M-). Each treatment had 20 repetitions. Weekly: height, mean diameter of coverage, leaf and pinnae number of plant individuals were recorded. After 20 weeks: fresh and dry biomass, relative growth rate, root/shoot ratio, real evapotranspiration, water use efficiency (WUE) and percentage of mycorrhizal colonization were determined. Later, dry treatment (M+ and M-) catclaw individuals were trasplanted to a semi-arid locality at the Mezquital Valley, in Central Mexico and their height, leaf number and survival was recorded monthly during one year. Results show that plants in the wet and mycorrhizal (WM+) treatment had grown higher, had larger plant coverage and had more pinnae than plants in the dry and mycorrhizal (DM+) treatment. Also, the mycorrhizal treatments (W and D) had higher WUE than plants in M-. In field conditions, after one year, survival of M+ plants was greater than witness. It was concluded that mycorrhization of M. biuncifera with native HMA inoculum increases its efficiency in biomass production (higher dry biomass per liter of irrigated water than non mycorrhizal plants) and that favors plant establishment and survival in field conditions. Finally, it could be recommended the AMF inoculation of catclaw plants to be used in revegetation programs of deteriorated semi-arid zones.