Ecophysiological responses of Eichhornia crassipes (Mart.) Solms to As⁵⁺ under different stress conditions

Abstract

Arsenic is a critical contaminant that is released into the environment through geochemical processes and anthropic actions. Two independent hydroponic experiments were performed to evaluate the ecophysiological responses of water hyacinth [Eichhornia crassipes (Mart.) Solms] to As under various stress conditions. In experiment 1, water hyacinth was exposed to As 5+ at concentrations of 0, 0.2, 2.0, and 20 mg L -1 for 0, 2, and 4 d; in experiment 2, water hyacinth was exposed at concentrations of 0, 0.025, 0.05, and 0.1 mg L -1 for 0, 10, and 20 d. In both experiments, As accumulation in plant tissue was proportional to its increase in the nutrient solution; As concentrations were higher in roots than in shoots. Detrimental effects of As on gas exchange were observed and were more pronounced in experiment 1. In experiment 1, at the beginning on the second day of exposure, significant decreases of maximum photochemical efficiency of PSII (F v /F m ), variable chlorophyll fluorescence (F v /F 0 ), and photosynthetic pigment contents were observed in plants exposed to 2.0 and 20 mg(As 5+ ) L -1 . It indicated that damage to the photosynthetic apparatus had occurred. No changes in F v /F m , F v /F 0 , and contents of photosynthetic pigments were observed in the plants grown in the presence of 0.2 mg(As 5+ ) L -1 (in experiment 1) or after any of the treatments in experiment 2, indicating plant tolerance. Elevated nonphotochemical quenching was observed in experiment 2 after 20 d of exposure to As; it was as a part of protection mechanisms of the photosynthetic apparatus in these plants. The results obtained here indicate that the use of water hyacinth for As 5+ removal from highly impacted environments is limited but that it is effective in remediating sites with a low contamination.

Effect of copper on the photosynthesis and growth of Eichhornia crassipes

“…Detrimental effects of pollutants (As 5+ ) on gas exchange of E. crassipes have been reported, and show that higher pollutant concentrations significant decrease F v /F m , variable chlorophyll fluorescence (F v /F 0 ) and pigment content; however, lower concentrations of pollutant did not affect these processes (Meneguelli‐Souza et al . 2016). Pereira et al .…”

“…These results are similar to those of Meneguelli‐Souza et al . (2016) and Lin & Jin (2018). Our results also indicate that Cu 2+ negatively affects photosynthetic electron transport efficiency of E. crassipes , as also found by Faseela et al .…”

Greater Performance of Exotic Elodea nuttallii in Response to Water Level May Make It a Better Invader Than Exotic Egeria densa During Winter and Spring

“…Similarly, there was no significant change in the total Chl content of the three species among different water depth treatments (Figure 4A). The maintenance of the photosynthetic pigment concentration (Chl concentration) explains the stability of F v/ F m (Meneguelli-Souza et al, 2016). These results suggested that 2 m or 3 m water depths did not cause damage to these three macrophytes, because they can tolerate a wide range of water depths (Vöge, 1994; Carrillo et al, 2006; Zhu et al, 2012; Li et al, 2013).…”

The effects of lead on photosynthetic performance of waxberry seedlings (Myrica rubra)

“…However, other reports contradict this finding. Meneguelli-Souza et al (2016) observed that q P and q N decreased significantly in water hyacinth (Eichhornia crassipes) on day 4 after treatment in the presence of 2.0 and 20 mg(As 5+ ) L -1 . Tanyolac et al (2007) found that both q P and q N showed decreasing trends in maize leaves exposed to 1.5 mM Cu for 12 d. Those authors suggested that the observed decrease in q N might be associated with the AOS generation caused by Cu stress.…”