Root Characteristics and Metal Uptake of Maize (Zea mays L.) under Extreme Soil Contamination

Agronomy

Anna Panozzo¹  Teofilo Vamerali¹  Cristian Dal Cortivo¹  Giuseppe Barion¹  Leila Radhouane²  Leila Romdhane² 

[1]Department of Agronomy, Food, Natural Resources, Animals and the Environment, University of Padua, Viale dell’Università 16, 35020 Legnaro, Italy

[2]National Institute of Agronomic Research of Tunisia (INRAT), University of Carthage, Rue Hédi Karray, 2049 Ariana, Tunisia

关键词: electrical conductivity;    maize;    root length and diameter;    soil metal contamination;    soil pore water;   

DOI  :  10.3390/agronomy11010178

来源: DOAJ

【 摘 要 】

Root characteristics and metal uptake in the maize hybrid Naudi were studied in a pot trial, using soil artificially highly polluted with Zn, Cu, Co, Cd, and Pb. The addition of these metals as sulfates decreased the soil pH and increased electrical conductivity. As a result of increased bioavailability in the soil pore water, significantly higher concentrations of metals, particularly Pb, Cu, and Co, were found in the shoot tissues of maize at the 3–4 leaf stage. While the lowest increase was in Cd (0.89 mg kg⁻¹ vs. 0.33 mg kg⁻¹ for controls), Zn reached a critical threshold of 75 mg kg⁻¹ vs. 2.76 mg kg⁻¹. Fresh and dry weights of shoots and roots, as well as root length, were markedly reduced, whereas root diameter, tip density, and the branching index increased considerably. A significant adaptation strategy by maize in the polluted soil was an increased fraction of coarse root length and a decreased fraction of finer roots. We conclude that maize is very sensitive to multiple metal pollution, suggesting its potential use as a test plant to evaluate contaminated soils. As length was the most affected root characteristic, measurement of this parameter could be a way of screening genotypes for tolerance to metal contamination and possibly salinity. There also is future scope for investigating whether K fertilization might mitigate metal phytotoxicity, in view of the negative correlations between the shoot K concentration and concentrations of the supplied metals.

【 授权许可】

Unknown