Response of Arbuscular Mycorrhizal Fungi to Hydrologic Gradients in the Rhizosphere of Phragmites australis (Cav.) Trin ex. Steudel Growing in the Sun Island Wetland.

Li Wang,Fang Ma,Zhe Li,Jieting Wu,Jixian Yang,Xue Zhang,Shiyang Li

doi:10.1155/2015/810124

Abstract

Within the rhizosphere, AM fungi are a sensitive variable to changes of botanic and environmental conditions, and they may interact with the biomass of plant and other microbes. During the vegetative period of the Phragmites australis growing in the Sun Island Wetland (SIW), the variations of AM fungi colonization were studied. Root samples of three hydrologic gradients generally showed AM fungi colonization, suggesting that AM fungi have the ability for adaptation to flooded habitats. There were direct and indirect hydrological related effects with respect to AM fungi biomass, which interacted simultaneously in the rhizosphere. Though water content in soil and reed growth parameters were both positively associated with AM fungi colonization, only the positive correlations between reed biomass parameters and the colonization could be expected, or both the host plant biomass and the AM fungi could be beneficial. The variations in response of host plant to the edaphic and hydrologic conditions may influence the effectiveness of the plant-mycorrhizal association. This study included a hydrologic component to better assess the role and distribution of AM fungi in wetland ecosystems. And because of that, the range of AM fungi was extended, since they actually showed a notable adaptability to hydrologic gradients.

Highlights

Interactions between plants and their rhizosphere microorganisms can significantly affect the corresponding ecosystem function
Regardless of the hydrologic gradient, mean values for the proportion of root segment colonized by hypha ranged from 13% to 20%, which were less variable than the vesicle colonization and the arbuscules colonization (Table 1)
The frequency and intensity of AM fungi colonization varied significantly between SIW1 and SIW3 both in summer and autumn, but there were no significant differences between SIW1 and SIW2

Summary

Introduction

Interactions between plants and their rhizosphere microorganisms can significantly affect the corresponding ecosystem function. One key microbial component of the rhizosphere is the arbuscular mycorrhizal fungi (AM fungi), which can form symbiotic relationships with the majority of terrestrial plant roots [1]. These ubiquitous fungi are grouped into the phylum Glomeromycota. The symbiosis may help plants to thrive by colonizing a wide soil volume, accelerating photosynthesis, protecting plants against plant pathogens and pests in soil, absorbing resources efficiently, and dissipating of pollutants from the soil [4, 6,7,8] They have the ability for adaptation to different conditions and being synergistic with indigenous soil microorganisms [9]. It has been proposed that AM fungi can increase the solubility of some immobile nutrients by releasing certain enzymes [10]

Methods

Results

Conclusion