A Hydroponic System for Growing Gnotobiotic Vs. Sterile Plants to Study Phytoremediation Processes

Abstract

In some phytoremediation studies it is desirable to separate and define the specific contribution of plants and root-colonizing bacteria towards contaminant removal. Separating the influence of plants and associated bacteria is a difficult task for soil root environments. Growing plants hydroponically provides more control over the biological factors in contaminant removal. In this study, a hydroponic system was designed to evaluate the role of sterile plant roots, rhizodeposition, and root-associated bacteria in the removal of a model contaminant, phenol. A strain of Pseudomonas pseudoalcaligenes that grows on phenol was inoculated onto plant roots. The introduced biofilm persisted in the root zone and promoted phenol removal over non-augmented controls. These findings indicate that this hydroponic system can be a valuable tool for phytoremediation studies that investigate the effects of biotic and abiotic factors on pollution remediation.

KEY WORDS:

• rhizosphere, phenol
• biofilm, gnotobiotic plant
• phytoremediation, bioremediation

ACKNOWLEDGMENTS

This research was partially supported by the Faculty of Civil and Environmental Engineering (Technion, Israel Institute of Technology) and Grand Water Research Institute at Technion (GWRI). We acknowledge two anonymous reviewers whose remarks helped improving the clarity and quality of the presentation.

*Member of Grand Water Research Institute, Technion, Haifa, Israel