Acid Rain and Ozone Influence Mycorrhizal Infection in Tree Seedlings

Atmospheric pollution may be causing reduced growth and increased mortality of trees in forests in Europe and North America. Acid rain and ozone are the two pollutants most frequently mentioned as causal agents in the forest decline problem. One plant-environment interface where atmospheric pollution may be having an impact is the symbiotic association between roots and soil fungi known as mycorrhizae. Mycorrhizae are essential for the survival and growth of most forest tree species in the natural environment. Mycorrhizal fungi can affect the nutrient uptake and translocation, water uptake, root morphology, carbon metabolism and disease resistance of the host plant. In specific instances, mycorrhizal infection has been observed to enhance tree growth increase seedling survival or protect plants from root disease. Therefore, sensitivity of the mycorrhizal association to atmospheric pollution could be harmful to forest trees and might influence the decline of forests.