Growth, physiological responses, and copper accumulation in seven willow species exposed to Cu—a hydroponic experiment

Abstract

Selecting plant species, especially woody species, that can tolerate and accumulate high levels of heavy metals is crucial for the purpose of phytoremediation. In the present study, seven willow species/clones were evaluated for their variations in copper (Cu) tolerance, Cu accumulation, and their relative physiological responses, when exposed to different doses of Cu (control, 15, and 120 μM) in a hydroponic system for 40 days. Upon Cu exposure, all tested willow species/clones (Salix, S.) remained relative normal growth, albeit with some visual evidence of Cu toxicity observed. Seven willow species remained relative high total biomass with tolerance index > 0.6 when being exposed to 120 μM Cu, suggesting their high Cu tolerance. Exposure to 120 μM Cu resulted in notable declines (16.3-76.1%) in photosynthesis in all willow species. Increases in the soluble sugar content and decreases in the soluble protein content in the leaves of five willow species (S. integra "Yizhibi", S. jiangsuensis "J172", S. matsudana 14, S. matsudana 25, S. matsudana 89) were found in the 120 μM Cu treatment. The majority of Cu mainly accumulated in the roots, ranging from 1916 to 26,244 mg kg DW. Principal component analysis and membership function analysis suggested that S. matsudana 89 and S. matsudana 25 showed much higher biomass and accumulation ability than the other species. This suggests that these two willow clones could be used as potential candidates for the phytostabilization of Cu in contaminated soils.

Biotreatment of pyrene and Cr(VI) combined water pollution by mixed bacteria

“…In this work, strains of these two genera were capable of simultaneous Cr(VI) removal and pyrene degradation. Roots and shoots are important plant organs that can be negatively affected by contacting with heavy metals, such as Cr, cadmium and copper 7,21,22 . Zong et al 7 showed that there were positive correlations between total Cr in peanuts and total root length, root surface area, and root volume, and that Cr(VI) at concentrations ranging from 75 to 100 µmol/L significantly decreased the root and shoot biomass of peanut.…”

Divergence in response of lettuce (var. ramosa Hort.) to copper oxide nanoparticles/microparticles as potential agricultural fertilizer

“…In previous studies, heavy metals of excessive dose can damage photosynthesis in terms of chlorophyll degradation []. Cao et al [22], also reported that excessive Cu (120 μM as CuSO 4 ) can severely reduce chlorophyll pigments, resulting in lower Gs and Pn. As a micronutrient, Cu at lower critical concentration is required to improve the plant development [24].…”

A Review on Effect of Copper and Iron Nanoparticle on Agricultural Crop

“…Wang et al (2019) Reported that the application CuO-NPs mixed with the soil were no significant change in Chl a content, intercellular CO 2 concentration or photosynthetic rate in leaves of lettuce while Cu-NPs @ 200 mg/kg were found Chl b in the lettuce leaves is decreased as compared with control. Cao et al (2018) revealed that the chlorophyll pigments were severely reduced by the excessive Cu (120 μM as CuSO 4 ) resulting the lower stomatal conductance and photosynthetic rate.…”