Zinc toxicity in plants: a review

BackgroundMetal contamination in soils affects both above- and belowground communities, including soil microorganisms. Ectomycorrhizal (ECM) fungi are an important component in belowground community and tolerant strains have great potential in enhancing plant-based remediation techniques. We assessed cadmium and zinc toxicity in five ECM species in liquid media (Hebeloma subsaponaceum;H. cylindrosporum;H. crustuliniforme;Sclerodermasp.;Austroboletus occidentalis) and investigated the potential of Zn to alleviate Cd toxicity. Due to highly divergent results reported in the literature, liquid and solid media were compared experimentally for the first time in terms of differential toxicity thresholds in Cd and Zn interactions.MethodsA wide range of Cd and Zn concentrations were applied to ectomycorrhizal fungi in axenic cultures (in mg L−1): 0; 1; 3; 9; 27; 81; 243 for the Cd treatments, and 0; 1; 30; 90; 270; 810; 2,430 for Zn. Combined Zn and Cd treatments were also applied toH. subsaponaceumandSclerodermasp. Dry weight was recorded after 30 days, and in case of solid medium treatments, radial growth was also measured.Results and DiscussionAll species were adversely affected by high levels of Cd and Zn, andA. occidentaliswas the most sensitive, with considerable biomass decrease at 1 mg L−1Cd, whileSclerodermasp. andH. subsaponaceumwere the most tolerant, which are species commonly found in highly contaminated sites. Cd was generally 10 times more toxic than Zn, which may explain why Zn had little impact in alleviating Cd effects. In some cases, Cd and Zn interactions led to a synergistic toxicity, depending on the concentrations applied and type of media used. Increased tolerance patterns were detected in fungi grown in solid medium and may be the cause of divergent toxicity thresholds found in the literature. Furthermore, solid medium allows measuring radial growth/mycelial density as endpoints which are informative and in this case appeared be related to the high tolerance indices found inH. subsaponaceum.

Download Full-text

Effect of phosphorus on zinc toxicity in tea pollen tube growth

Soil Science & Plant Nutrition ◽

10.1080/00380768.1998.10414447 ◽

1998 ◽

Vol 44 (2) ◽

pp. 261-264 ◽

Cited By ~ 1

Author(s):

Chun Lan Lian ◽

Hiromi Yokota ◽

Gang Wang ◽

Shigeki Konishi

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Tube Growth ◽

Zinc Toxicity

Download Full-text

Effect of Soil and Foliar Silicon Application on the Reduction of Zinc Toxicity in Wheat

Agriculture ◽

10.3390/agriculture10110522 ◽

2020 ◽

Vol 10 (11) ◽

pp. 522 ◽

Cited By ~ 1

Author(s):

Aleksandra Zajaczkowska ◽

Jolanta Korzeniowska ◽

Urszula Sienkiewicz-Cholewa

Keyword(s):

Sodium Silicate ◽

Plant Biomass ◽

Foliar Application ◽

Zinc Toxicity ◽

Soil Application ◽

Zn Concentration ◽

Drastic Increase ◽

Applied Dose ◽

Negative Effect ◽

Si Content

The aim of the study was to compare soil and foliar application of Si to relieve stress in wheat caused by excess Zn in the soil. Two pot experiments were carried out in which the soil was contaminated with zinc sulphate at the dose of 600 mg kg−1 Zn before sowing. Si was applied in the soil in the following doses 200 mg kg−1 and 400 mg kg−1 Si and as foliar spraying in concentrations 2 mM L−1 and 6 mM L−1 Si in the form of sodium silicate. The applied dose of Zn was toxic to wheat and caused a significant decrease in the biomass of shoots and roots. Soil application of Si reduced the negative effect of Zn on plants and significantly increased the biomass of the tested organs. The foliar application of Si did not reduce the decrease of plant biomass. Soil contamination with Zn caused a drastic increase in Zn concentration in shoots and roots, while Si applied in the soil significantly decreased this concentration. The increase in soil pH, which was caused by sodium silicate, also affected the decrease in Zn concentration in plants. The plants absorbed Si applied to the soil, which is indicated by an increase in the Si content in shoots compared to the control. In the case of foliar spraying, only a higher dose of Si increased its concentration in the plants. The application of Si in the soil, in contrast to foliar application, reduced the transfer of Zn from roots to shoots. The higher effectiveness of soil application of Si than foliar application in alleviating the toxicity of Zn was associated with both an increase in pH and a higher uptake of Si by plants.

Download Full-text