Effects of antibiotics on nitrogen uptake of four wetland plant species grown under hydroponic culture.

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 µg L-1 Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH4+-N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO3-. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO3--N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.

A comparative study of anti-Candida activity and phenolic contents of the calluses from Lythrum salicaria L. in different treatments.

In the study, anti-Candida activity and phenol contents of Lythrum salicaria L. calli and wild species have been evaluated. The seeds of L. salicaria (Lythraceae), collected from Lahidjan City in the north of Iran, were cultured in Murashige and Skoog medium (MSM) with a supplement, gibberellin, to germinate. Callus inductions were performed from segments of seedling on MSM containing different concentrations of plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The activity of calluses extracts, wild plant, gallic acid, and 3,3',4'-tri-O-methylellagic acid-4-O-ß-D-glucopyranoside (TMEG) as the main phenolic compounds against Candida albicans was assessed using cup plate diffusion method. The total phenols contents of calli and wild plant extracts were analyzed using Folin-Ciocalteu reagent. The callus formation in MSM supplemented with various concentrations of 2,4-D and BAP were 0-100 %. Anti-Candida activity of callus extract which obtained from MSM supplemented with 2,4-D and BAP (1 mgdm(-3)) was similar to the wild plant extract. Minimum inhibitory concentration values of gallic acid and TMEG were obtained as 0.312 and 2.5 mgcm(-3), respectively. Gallic acid equivalent values in all treatments were from 0 to 288 µg GAE mg(-1). Phenolic contents of plant aerial parts (331±3.7 µg GAE mg(-1)) and the callus, which developed in MSM including 1 mgdm(-3) of both 2,4-D and BAP, showed the same phenolic value and exhibited anti-Candida extract activity.

Effects of lead contamination on the growth of lythrum salicaria (purple loosestrife).

The ability of individual species to tolerate or accumulate heavy metal pollutants has been investigated widely. Although invasive species may become established more easily in disturbed environments, relatively little is known about how an ability to tolerate pollutants might give invasive species a competitive advantage. This study is part of a series of experiments investigating native and invasive species interactions with chemical pollution and other forms of disturbance. The purpose of this experiment was to investigate the effects of lead on the growth of Lythrum salicaria. We exposed plants to different concentrations of lead and measured different growth parameters, such as biomass, length, leaf number, and biomass allocation to roots. For most measures, plants grown in lead-free conditions were larger than plants exposed to lead. Plants in the low (500 mg/l) and medium (1,000 mg/l) lead treatments did not differ from each other, while plants in the high (2,000 mg/l) lead treatment were significantly smaller. However, the biomass allocation to roots was not significantly different among treatments. Although their growth is affected, individuals of Lythrum salicaria demonstrated tolerance to lead contamination, which may aid in their colonization in lead-polluted wetlands.