Separation of Antioxidant-Rich Alternanthera Sessilis Red Extracts by Sephadex LH-20 and Identification of Polyphenols Using HPLC-QToF-MS/MS

This study aimed to fractionate Alternanthera sessilis Red (ASR) crude extracts and determine their antioxidant activities as well as the related active components in the whole plant. ASR was extracted with water and ethanol, and further separated using a Sephadex LH-20 column. Following the assessments of the polyphenolic contents and antioxidant activities of crude extracts (H₂O_ASR and EtOH_ASR) and fractions, a HPLC-QToF analysis was performed on the crude extracts and selected fractions (H₂O_ASR FII and EtOH_ASR FII). Three water fractions (H₂O_ASR FI, FII and FIII) and four ethanolic fractions (EtOH_ASR FI, FII, FIII and FIV) were derived from their crude extracts, respectively. EtOH_ASR FII exhibited the greatest total phenolic content (120.41 mg GAE/g fraction), total flavonoid content (223.07 mg RE/g fraction), and antioxidant activities (DPPH IC₅₀=159.43 μg/mL; FRAP=1.93 mmol Fe²⁺/g fraction; TEAC=0.90 mmol TE/g fraction). Correlation analysis showed significant (p<0.01) positive correlations between both TPC (r=0.748–0.970) and TFC (r=0.686–0.949) with antioxidant activities in the crude extracts and fractions. Flavonoids were the major compounds in the four selected samples tentatively identified using HPLC-QToF-MS/MS, with the highest number of 30 polyphenol compounds detected in the most active fraction, EtOH_ASR FII.     

Plasticity and ontogenetic drift of biomass allocation in response to above- and below-ground resource availabilities in perennial herbs: a case study of <Emphasis Type="Italic">Alternanthera philoxeroides</Emphasis>

Changes in plant biomass allocation in response to varying resource availabilities may result from ontogenetic drift caused by allometric growth (i.e., apparent plasticity), a true adjustment of ontogenetic trajectories (true plasticity) or both (complex plasticity). Given that the root allocation of annual species usually decreases during the growth, the developmentally explicit model predicts that annual herbs will exhibit true plasticity in root allocation under above-ground resource limitation and apparent plasticity for moderate stress of below-ground resource. For perennial species, the root allocation of which increases during growth, the reverse patterns would be expected. In this study, we tested the developmentally explicit model with a perennial weed, Alternanthera philoxeroides (Mart.) Griseb. We report its adaptive changes and ontogenetic drift of root allocation in response to different resource levels (i.e., light, water and nutrient availability) by comparing root allocation on both an age and a size basis. The root allocation of A. philoxeroides increased with the size (i.e., ontogenetic drift) during the growth, and exhibited significant changes in response to different resource availabilities. Furthermore, the root allocation in response to water or nutrient availability exhibited typical complex plasticity, while the light stress only slowed down the growth, with the ontogenetic trajectory unchanged (apparent plasticity). The contrasting responses to above-ground and below-ground stresses were consistent with the prediction of the developmentally explicit model.     

Screening of Native Hyperaccumulators at the Huayuan River Contaminated by Heavy Metals

Plant, soil, and sediment samples were taken from the Fuqiao area within the Huayuan River basin in South China. Concentrations of manganese, zinc, cadmium, and lead in the samples were measured, and the characteristics of the plant samples to absorb, transfer, and accumulate the target metals were analyzed. It was indicated that the concentrations of target metals in 13 plant samples greatly exceeded the background values of target metals in plants over the world, and that the plant species might evolve to the accumulating ecotypes for the target metals under the long-term stress from the contaminated environment. Among 13 plant species, Alternanthera philoxeroides exhibited the highest accumulation capacities for the target metals, amounting to 6511, 13,784, 155, and 104 mg/kg in its shoots for manganese, zinc, cadmium, and lead, respectively. Its bioaccumulation coefficients for manganese, zinc, cadmium, and lead were 5.08, 49.23, 36.78, and 34.81, respectively, and its transfer factors for manganese, zinc, cadmium, and lead were 7.53, 3.19, 7.38, and 1.29, respectively. The results showed that Alternanthera philoxeroides satisfied the criteria for the hyperaccumulator for zinc and cadmium, and that it might be a potential native plant species for phytoremediation of the contaminated soil, sediment, and river water by the target metals within the basin.     

Potential of joyweed Alternanthera sessilis for rapid treatment of domestic sewage in SHEFROL® bioreactor

In a first-ever report on this subject, it is shown that a common amphibious plant joyweed (Alternanthera sessilis) can be used in rapid and efficient treatment of biodegradable wastewaters, typified by domestic sewage. The plant was effective when used indoors under artificial lighting, as well as outdoors. It enabled treatment of sewage, varying widely in strength (from 300?mg/L to 1800?mg/L in chemical oxygen demand), to the extent of 78.9–83.9%. It was also able to remove biological oxygen demand, suspended solids, phosphorous, nitrogen, and the heavy metal copper to the extent of 87%, 93%, 45%, and 43%, respectively. Over 99% of total coliforms, faecal coliforms, and faecal streptococci were also removed. The treatment was very swiftly achieved, at a hydraulic retention time of just 6?h, in the “sheet flow root level” (SHEFROL^®) bioreactor developed earlier by us and of which a patent claim has been registered. The findings indicate that A. sessilis has the potential to affect primary, secondary, and tertiary treatment of domestic sewage along with significant pathogen removal in a single process step when used in SHEFROL^® bioreactors.