The Response of Red Clover (Trifolium pratense L.) to Separate and Mixed Inoculations with Rhizobium leguminosarum and Azospirillum brasilense in Presence of Polycyclic Aromatic Hydrocarbons.

Jarosław Grządziel,Karolina Furtak,Anna Gałązka,Karolina Gawryjołek

doi:10.3390/ijerph17165751

Abstract

This study aimed to evaluate the impact of co-inoculation Rhizobium sp. and Azospirillum sp. on plant (Trifolium pratense L.) growth in the presence of polycyclic aromatic hydrocarbon (PAH) contamination (anthracene, phenanthrene, and pyrene). Eight strains from the genus Rhizobium leguminosarum bv. trifolii were selected for biotest analysis. Two methods of inoculation were used in the chamber experiment: (1) R. leguminosarum alone and (2) a combined inoculant (R. leguminosarum and Azospirillum brasilense). For comparison, non-contaminated controls were also used. The results demonstrated that co-inoculation of plants with Rhizobium and Azospirillum resulted in more root and shoot biomass than in plants inoculated with R. leguminosarum alone. The results indicated that application of a co-inoculation of bacteria from Rhizobium and Azospirillum species had a positive effect on clover nodulation and growth under the condition of PAH contamination.

Highlights

Polycyclic aromatic hydrocarbons (PAHs) are a group of over 200 compounds containing between two and several dozen aromatic rings per molecule
It has been reported that PAHs can be genotoxic for plants
The literature data indicate that white clover (T. repens) is highly sensitive to contamination with organic and inorganic compounds, which may suggest the sensitivity of other plants of this type to PAHs such as the red clover (T. pratense) used in the presented experiment [4]

Summary

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are a group of over 200 compounds containing between two and several dozen aromatic rings per molecule. Their occurrence in the environment is mainly related to human activity; natural sources such as crude oil and volcanic eruptions supply a small amount of them [1]. PAHs are accumulated in algae, invertebrates, and aquatic plants and are transferred to higher trophic levels [2]. The accumulation of these contaminants in plant tissues poses a threat. It is important to study the problem of PAH contamination in the context of its impact on plants and the effects of various groups of microorganisms on the growth rate and soil quality and plants in contaminated areas

Objectives

Methods

Conclusion