Resumen

VALDES RAMIREZ, María. Climatic change and the symbiotic state of the forest trees. Rev. mex. de cienc. forestales [online]. 2011, vol.2, n.5, pp.05-13. ISSN 2007-1132.

The unanimous world agreement to reduce the greenhouse effect gas emissions to the atmosphere leads to consider the forms to contribute to the above mentioned labor with scientific arguments. Mexico's Special Program for Climatic Change points out that 30% could succeed with the prevention of deforestation and woodland degradation and the recovery of forest areas. Different terrestrial ecosystems have the ability to sequestrate carbon through plants and soil. The microbial biomass in the rhizosphere is up to 10 times higher than that of soil; these microorganisms transform the organic matter into humus, which is the most stable C. Root biomass is higher with the presence of symbiotic microorganisms (ectomycorrhizal, arbuscural-mycorrhyzal, nitrogen-fixing); root symbiotic fungi are a main factor in maintaining the biodiversity and the ecosystem. High CO₂ and atmospheric O₃, affect symbiosis of trees as well as the altered nitrogen cycle (excess), temperature and modified precipitation, invasive species and the phytophatogens presence. The factors that participate in global change interact and have an impact on the mycorrhiza, direct and indirectly. They have an effect upon edaphic biota, as they impact the composition of the mycorryzal fungi community, on the stimulating bacteria of mycorrhization, on the plants that act as reservoir for symbionts, the invasion of non-mycorryzal plants, etc. Mycorrhiza are crucial in the soil - plant interphase, and by their influence in plant physiology and their communities, they must be included in the ecological studies about climate change.

Palabras llave : Climatic change; carbon sequestration; deforestation; greenhouse effect; ectomhicorrizae; micorrhizal fungi.