Inhibitory effect of municipal sewage on symbiosis between mangrove plants and arbuscular mycorrhizal fungi

Abstract

The impact of municipal sewage discharge on the symbiosis between arbuscular mycorrhizal fungi (AMF) and mangrove plants in different sections along 2 constructed mangrove belts was evaluated. Each section was 33 m long and 3 m wide and planted with Kandelia obovata or Aegiceras corniculatum, the 2 most common mangrove plants in South China. A greenhouse experiment comparing the colonization intensity of AMF among different mangrove plant species under wastewater treatment was also conducted. Typical arbuscular mycorrhiza structures were observed in most of the root samples collected from the constructed belts. In both belts, the AMF colonization intensities were significantly lower in the roots of plants close to the inlet than in those further away from the influent, suggesting that the colonization intensity of AMF was inhibited by municipal sewage discharge, and that inhibition was least pronounced in the effluent where the concentration of nutrients was lowest. AMF colonization intensities in the roots of A. corniculatum were significantly higher than those in the roots of K. obovata, which could be attributed to the fact that A. corniculatum provided more oxygen to support the AMF than did K. obovata, indicating the strong effects of the host species on AMF colonization. In both constructed wetland belts and greenhouse experiments, the AMF vesicle and arbuscular structures (the main functional structure of arbuscular mycorrhiza) appeared to be more sensitive to wastewater discharge than the hyphal structure, implying that sewage discharge would reduce the potential beneficial effects of AMF in mangrove ecosystems. This study provides useful information on the responses of AMF to sewage; this knowledge is important for the conservation and restoration of mangrove forests that are located close to human activities.

Community Dynamics of Arbuscular Mycorrhizal Fungi in High-Input and Intensively Irrigated Rice Cultivation Systems

“…The presence of AMF in wetland ecosystems has received increased attention in recent years (7,9,32,33), but only a few field studies documenting AMF colonization have been conducted in paddy wetlands (2). In agreement with Watanarojanaporn et al (13), who reported that AMF are commonly present in rice roots from conventional paddy wetlands in Thailand, we found that AMF colonization in rice roots is commonly present at the heading and ripening stages though absent or rare at the early growth stages.…”

Diverse Arbuscular Mycorrhizal Fungi (AMF) Communities Colonize Plants Inhabiting a Constructed Wetland for Wastewater Treatment

“…According to Carvalho et al [2], high levels of salinity negatively affect AMF establishment inside roots. Moreover, Wang et al [38] also reported that the intensity of AMF colonization in two mangrove species was highly dependent on the concentration of nutrients present in a municipal effluent, since high levels of N, P, and organic matter decreased AMF colonization. The observed changes in the composition and diversity of AMF's communities can be related to fluctuations in the wastewater organic load in the CW throughout different seasons/years.…”

Diversity Status of Arbuscular Mycorrhizal (AM) Fungi in Association with Selected Mangrove Plants in Tamil Nadu

“…Among them, Glomus mosseae exhibited highest frequency at all inundation types; Glomus fistulosum, Sclerocystis coremioides and Glomus mosseae showed highest relative abundance at sites inundated by usual springtides, summer springtides and diurnal tides, respectively. Similarly, Wang et al (2010;2014) studied AM fungal association with two mangrove swamps in south China and found AM fungi in the form of hyphae which were commonly associated with all the mangrove species and six AM fungal species belonging to two genera viz., Glomus and Acaulospora were identified by them.…”