Phytotoxicity induced by Phragmites australis: an assessment of phenotypic and physiological parameters involved in germination process and growth of receptor plant

Abstract

This study investigated the possible phytotoxicity induced by Phargmites australis on phenotypic and physiological parameters of recipient plants with identification of major inhibitors in the donor plant. This was achieved using aqueous extracts of different organs and root exudates of P. australis in laboratory and greenhouse experiments with Lactuca sativa as the model test plant. The observed reduced liquid imbibition and altered resource mobilization in seeds of L. sativa, in particular an insufficient carbohydrate supply, demonstrated that the onset of germination might be negatively affected by phytotoxicity. Dose-response studies pointed out that oxidative stress through reactive oxygen species production could potentially cause the observed germination and seedling growth reductions. The osmotic effects by mannitol solution on germination as well as growth and physiology at a level of (0.57 and (0.45 bar, respectively, demonstrated that the results from aqueous plant extracts were partially induced by the osmotic potential on and above those levels. Overall, the relative strength of inhibition on measured parameters was the highest in leaf extract, followed by rhizome, root, stem, and inflorescence. Root exudates of P. australis also had negative impacts by reducing germination and growth of plant. High-performance liquid chromatography (HPLC) analysis revealed gallic acid, a potent phytotoxin, as a major compound with an order of leaf ! inflorescence ! rhizome !root ! stem.

Identification and Phytotoxicity Assessment of Phenolic Compounds in Chrysanthemoides monilifera subsp. monilifera (Boneseed)

“…The supernatant was double filtered through 0.2 μm phenomenex regenerated cellulose (RC) membrane to prepare it for HPLC analysis. Known phytotoxic phenolic compounds (gallic acid, catechin, epicatechin, p-coumaric acid, ferulic acid, phloridzin, arbutin, hydroxymethylfuraldehyde (HMF), gentic acid, chlorogenic acid and rutin) that fall within the capacity of the HPLC column [ 37 ] were included for potential identification in boneseed. After a few trials, the presence of catechin, p-coumaric acid, ferulic acid and phloridzin was confirmed and subsequent analyses concentrated on only those four compounds.…”

Allelopathic influence of common buckwheat root residues on selected weed species

“…The degree of plasma membrane damage, expressed as leakage of electrolytes, was determined by the method described by Uddin et al (2014) using a conductivity meter (HACH conductivity/TDS meter 44600-00, Poland).…”

Long-term effects of a Phragmites australis invasion on birds in a Lake Erie coastal marsh

“…Decreases in plant species richness following invasion are most pronounced in freshwater marshes (Meyerson et al, 2000), where reductions in species richness are correlated to the density of P. australis stems (Lenssen et al, 2000;Price et al, 2014), suggesting an effect of competition between P. australis and native plant species. Some attribute this to the production of allelopathic gallic acid by invasive P. australis (Rudrappa et al, 2007;Uddin et al, 2014), thought this remains controversial (Weidenhamer et al, 2013). Given the rapid shoot production, long growing season, and great height and density of most P. australis; it is capable of decreasing available sunlight for native plants (Hirtreiter and Potts, 2012).…”