Phenology and nurse plant of Sotoa confusa (Garay) Salazar (Orchidaceae) in the Southern Potosino Zacatecano Highlands

Sotoa confusa is a little conspicuous terrestrial orchid that is distributed in arid and semi-arid land of Mexico and south of USA, its life history is poorly known, so phenology and interaction of this species with shrubs was studied; its bloom occurs in March and fructifies in April (the driest period of the year), latter, from July to September it develops leaves, which disappear in October, so this orchid remains eight months without leaves. By other hand, S. confusa does not grow in areas with bare soil, so it shows preference to grow under the canopy of plants such as Dodonaea viscosa, Opuntia imbricata, O. robusta, O. leucotricha and Pittocaulon praecox; however, it shows a negative association with Jatropha dioica. The survival strategy of this plant in arid environments is to grow under the canopy of other plants that provide a favorable microclimate and develop leaves only during rainy seasons.

Establecimiento de plantas mediante el uso de micorrizas y de islas de recursos en un matorral xerófilo deteriorado

Survival of mesquite (Prosopis laevigata) and huizache (Acacia farnesiana), previously inoculated with arbuscular mycorrhizal fungi (AMF) was analyzed in field conditions during one year. The plants were cultivated for nine months in a greenhouse, two months in a nursery, and then they were transplanted in a deteriorated xeric shrub ecosystem located in Actopan Valley, Hidalgo State, Mexico. Each individual (either inoculated or not inoculated with AMF), was transplanted under the cover of one of eight nurse plant species forming resource islands, in order to evaluate the effects of mycorrhizal inoculum and nurse plant identity on plant establishment and survival during the dry period (October to April). Overall, results show that inoculated mesquite and huizache plants had a significant increase in percent survival, raising from 19 to 54% for P. laevigata, and from 18 to 48% for A. farnesiana. Regarding nurse plant identity, i.e. resource island type, there were not significant differences in percent survival of transplanted individuals. The experiment also showed that inoculated plants had a larger number of pinnae than their controls. On this basis, inoculation of seedlings with AMF is recommended to restore deteriorated semi-arid ecosystems