Non-native Phragmites australis (common reed) is an aggressive invader of wetland environments throughout North America. Current management tactics often rely on resource-intensive manual removal or involve the use of chemical herbicides, so new treatments are being developed. Previous work demonstrated that the application of organic acids negatively impacted the growth of root biofilms in P. australis. These biofilms and microbes in the plant rhizosphere can play an important role in nutrient acquisition and plant growth, but it isn’t clear if the symbiotic relationships between P. australis and its affiliate microbial community can be manipulated to regulate plant success. Therefore, several of salts and formulations of two organic acids, butyric and acetic, were applied to P. australis plants to determine if the treatments inhibited plant growth. P. australis plants from two populations (New Jersey and Michigan) were treated with nine 0.5 M solutions of sodium butyrate, calcium butyrate, sodium acetate, calcium acetate, equal parts sodium butyrate and sodium acetate, equal parts calcium butyrate and calcium acetate, and tributyrin. A pelletized form of sodium butyrate (Novyrate™) was also tested, and untreated plants were grown as a control. Plants were grown outside in standardized containers for 79 days during the summer of 2018. The growth medium was continually saturated with treatment solution or water for the study’s duration. Plant stress and growth data were collected every 2-3 days, including original stem height and diameter, proportion of leaves that appeared green, plant health as evaluated using stress-detection lenses, and the number and height of any daughter tillers. A similar study was carried out at Rutgers University under greenhouse conditions.
Results/Conclusions
All organic acid treatments significantly reduced growth (>50% biomass) of P. australis compared to the control plants. Original stem height, aboveground biomass, belowground biomass, the number of primary roots, and the number and heights of daughter tillers were significantly reduced in plants subjected to organic acid treatments, regardless of origin population. Impacts were most pronounced in the tributyrin and calcium butyrate treatments. These results demonstrate that organic acids can significantly inhibit the growth of P. australis plants originating from different populations. Previous work suggests that this effect is likely achieved through inhibition of rhizosphere bacteria, and our results suggest that such a relationship could be manipulated as a viable alternative for removal and management of P. australis in invaded areas.