Differential effects of two explosive compounds on seed germination and seedling morphology of a woody shrub, Morella cerifera

Abstract

Soils contaminated with explosive compounds occur on a global scale. Research demolition explosive (RDX) (hexahydro-1,3,5-trinitro-1,3,5-triazine) and trinitrotoluene (TNT) (2-methyl-1,3,5-trinitrobenzene) are the most common explosive compounds in the environment. These compounds, by variably impacting plant health, can affect species establishment in contaminated areas. Our objective was to quantify comparative effects of RDX and TNT on a woody shrub, Morella cerifera, commonly found on bombing ranges along the Atlantic Coast of the United States. Two life stages of M. cerifera, Seeds and juvenile plants, were exposed to soil amended with concentrations of RDX and TNT representative of field levels; RDX up to 1,500 ppm and TNT up to 900 ppm. Percent germination was recorded for 3 weeks; morphological metrics of necrotic, reduced, and curled leaves, in addition to shoot length and number measured at the end of the experiment (8 weeks) for juvenile plants. All concentrations of RDX inhibited seed germination while TNT did not have an effect at any concentration. As contaminant concentration increased, significant increases in seedling morphological damage occurred in the presence of RDX, whereas TNT did not affect seedling morphology at any concentration. Overall the plants were more sensitive to the presence of RDX. Species specific responses to explosive compounds in the soil have the potential to act as a physiological filter, altering plant recruitment and establishment. This filtering of species may have a number of large scale impacts including: altering species composition and ecological succession.

Remote Sensing of Explosives-Induced Stress in Plants: Hyperspectral Imaging Analysis for Remote Detection of Unexploded Threats

“…However, HSI did differentiate between drought and anthropogenic stress from RDX. To ensure plants exposed to RDX would be able to germinate, those seeds were started in clean soil and then transplanted to contaminated soil as explosives are known to inhibit germination of some species [35]. Seeds of other groups were started in clean soil.…”

Genetic modification of western wheatgrass (Pascopyrum smithii) for the phytoremediation of RDX and TNT

“…On live-fire training ranges, deposition of RDX and TNT onto soils around targets is ongoing and thus a continuing source of soil and groundwater contamination. Phytoremediation could be a relatively lowcost method to contain and clean-up these sites but many plant species grow poorly in RDX and TNT contaminated soil (Vila et al 2007;Via and Zinnert 2016;Panz and Miksch 2012;Via et al 2015) and are not able to degrade significant amounts of RDX (Best et al 1999;Yoon et al 2006;Best et al 2006).…”

Right on target: using plants and microbes to remediate explosives

“…Novel studies have quantified the response to explosives of plant species native to military ranges in temperate regions. By measuring multiple variables representing morphological and physiological responses, such studies identified vegetation responses that could potentially be used to determine levels of TNT and RDX contamination (Ali et al 2014;Via and Zinnert 2016;Via et al 2017Via et al , 2015. Hyperspectral imaging technologies are also being developed to remotely detect vegetation response (Naumann et al 2010) using aerial drones as suitable carriers to record contamination levels on surfaceinaccessible sites.…”