Plant symbiotic microorganisms in acid sulfate soil: significance in the growth of pioneer plants

Abstract

Acid sulfate soil is generated by chemical and microbial oxidization of sulfide-rich minerals/sediments. Although revegetation of the soil is difficult due to low-pH and poor nutrient availability, pioneer plants may adapt to such an extreme environment via associating with mycorrhizal fungi and/or N-fixing bacteria for acquisition of mineral nutrients. In this study, an abandoned quarry in which acid sulfate soil was found was chosen to investigate the influence of soil acidity on the levels of colonization by the microsymbionts, the identities of the microsymbionts that associated with pioneer plants and the dependency of pioneer plants on the microsymbionts. The levels of arbuscular mycorrhizal (AM) colonization in pioneer grass, forbs and legume shrubs grown in the field were assessed, and no significant decline in the levels with an increase in soil acidity was observed. Most of the legume shrubs formed root nodules. Several AM fungi and bradyrhizobia were cultured from the rhizosphere soils of pioneer plants grown in the quarry and identified based on the sequences of the small subunit ribosomal RNA genes. Pot experiments revealed that the microsymbionts isolated from the field significantly promoted the growths of pioneer grasses and legume shrubs in acid sulfate soil at pH 3.4. These results suggest that plant-microbial symbiotic associations play significant roles in the growth of pioneer plants in acid sulfate soil

Sulfide as a soil phytotoxin—a review

“…For the marsh plant Spartina spp., it has been shown that the combination of proton toxicity and concomitant mobilization of Al may have contributed to die-off events during droughts (McKee et al, 2004). It has been suggested that acid-tolerant arbuscular mycorrhizal fungi may play an important role in the establishment of pioneer species (grasses, forbs and shrubs) on dry acid sulfate soils (Maki et al, 2008). …”

The lime–silicate question

“…AMF occur in acid soils, even with such low pH-values of 2.7 (Cumming and Ning, 2003;Maki et al, 2008;Taheri and Bever, 2010;Seguel et al, 2013) and can be symbiotically cultivated under such conditions (Cavallazzi et al, 2007;Hu et al, 2013). Spores of Acaulospora laevis occur in soil of very low pH, whereas Glomus sp.…”

Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists

“…Soil acidity also constrains plant productivity; inhibition of root elongation and reduction of phosphorus (P) solubility in the soil solution lead to serious P deficiency in plants [ 6 , 7 , 8 ]. Arbuscular mycorrhizal (AM) fungi are the obligate biotrophs that associate with most land plants, deliver phosphorus (P) to the host plant [ 9 ], and thus play a significant role in the establishment of early-successional species in acidic soil [ 10 , 11 ].…”