Influence of adverse soil conditions on the formation and function of Arbuscular mycorrhizas

Abstract

The majority of plants have mycorrhizal fungi associated with them. Mycorrhizal fungi are ecologically significant because they form relationships in and on the roots of a host plant in a symbiotic association. The host plant provides the fungus with soluble carbon sources, and the fungus provides the host plant with an increased capacity to absorb water and nutrients from the soil. Adverse conditions are a pervasive feature in both natural and agronomic soils. The soil environment is constantly changing with regard to moisture, temperature and nutrient availability. In addition, soil properties are often manipulated to improve crop yields. In many cases, soils may be contaminated through disposal of chemicals that are toxic to plants and microorganisms. The formation and function of mycorrhizal relationships are affected by edaphic conditions such as soil composition, moisture, temperature, pH, cation exchange capacity, and also by anthropogenic stressors including soil compaction, metals and pesticides. Arbuscular mycorrhizal fungi are of interest for their reported roles in alleviation of diverse soil-associated plant stressors, including those induced by metals and polychlorinated aliphatic and phenolic pollutants. Much mycorrhizal research has investigated the impact of extremes in water, temperature, pH and inorganic nutrient availability on mycorrhizal formation and nutrient acquisition. Evaluation of the efficacy of plant-mycorrhizal associations to remediate soils contaminated with toxic materials deserves increased attention. Before the full potential benefits of arbuscular mycorrhizal fungi to reclaim contaminated soils can be realized, research advances are needed to improve our understanding of the physiology of mycorrhizae subjected to adverse physical and chemical conditions. This paper will review literature and discuss the implications of soil contamination on formation and function of arbuscular mycorrhizal associations. C

Seasonal dynamics of arbuscular mycorrhizal fungi in plants of Theobroma grandiflorum Schum and Paullinia cupana Mart. of aN agroforestry system in Central Amazonia, Amazonas State, Brazil

“…The results of this investigation give some support to a strong influence of edaphic factors, such as soil moisture, pH, ECEC, Mg, K and Mn (16,40,41,42,52) on symbiotic association in the acid soils and nutrient-limited soils of Central Amazonia. According to Hayman (24), level of soil fertility is believed to be an important factor influencing the AMF population.…”

“…Environmental factors that affect and alter soil microbial assemblage structure and function are complex. It is well known that environmental variables, such as soil pH, nutrient availability and soil moisture content, can influence the distribution and activity of soil microorganisms (2,16). In terra firme ecosystems in Amazonia, high soil acidity and low fertility are limit microbial activities.…”

Soil Compaction - Impact of Harvesters' and Forwarders' Passages on Plant Growth

“…Soil compaction also affects the structure, development and function of mycorrhizas (Entry et al, 2002) and causes changes in the levels of stress hormones in plants, mainly abscisic acid and ethylene (Kozlowski, 1999).…”

Arbuscular mycorrhiza of plants spontaneously colonizing the soda heap in Jaworzno (southern Poland)

“…Arbuscular mycorrhizae (AM) alleviate many anthropogenic stresses, including those caused by heavy metals and toxic inorganic and organic substances deposited in the soil, as well as those resulting from too high compaction and pH of soil (Schüepp et al 1987;Gildon and Tinker 1983;Weissenhorn et al 1995;Entry et al 2002). Additionally, AMF improve natural succession of plants in habitats where their colonization is slow, e.g., on sand dunes (Sylvia and Will 1988;Corkidi and Rincon 1997a, b) and contaminated areas such as industrial wastes (Khan 1978;Hetrick et al 1994;Gucwa-Przepióra and Turnau 2001).…”