Abstract

Grass species native to South American can have mechanisms to tolerate copper (Cu) excess, which improves their use to phytoremediate Cu-contaminated soils . The aims of the present study are to assess the tolerance of grass species native to South American grasslands to copper-contaminated soils, as well as their adaptive responses under high Cu-stressed condition and to identify native grass species presenting the highest potential to be used for phytoremediation purposes. Soil samples were air-dried and their acidity, phosphorus and potassium levels were corrected, and the samples were incubated. Three Cu levels were used in the experiment: natural (Dose 0), with added of 40 mg kg⁻¹ of Cu and with added of 80 mg kg⁻¹ of Cu. Three Axonopus affinis, Paspalum notatum and Paspalum plicatulum seedlings were transferred to 5-L pots filled with soil in August and grown for 121 days. Soil solution was collected during cultivation with the aid of Rhizon lysimeters. Main concentrations of cations and anions, dissolved organic carbon and pH in the soil solution were analyzed and the ionic speciation was carried out. Cu toxicity impaired the growth of grass species native to South America, since Cu excess led to both changes in root morphology and nutritional unbalance. Among all assessed native species, Paspalum plicatulum was the one presenting the greatest potential to phytostabilize in Cu-contaminated soils, since it mainly accumulates Cu absorbed in the roots; therefore, its intercropping with grapevines is can be beneficial in Cu-contaminated soils.

摘要

南美原产的草种可以具有耐受铜（Cu）过量的机制，从而改善了其对植物修复的Cu污染土壤的利用。本研究的目的是评估南美草原原生草种对铜污染土壤的耐受性，以及它们在高铜胁迫条件下的适应性反应，并确定具有最高使用潜力的原生草种。用于植物修复。风干土壤样品并校正其酸度，磷和钾水平，然后将样品孵育。实验中使用了三种铜含量：天然（剂量0），添加了40 mg kg ^-1的铜和添加了80 mg kg ^-1的铜。三个轴突亲属，八月将Paspalum notatum和Paspalum plicatulum幼苗转移到装满土壤的5-L花盆中，并生长121天。在耕作过程中借助Rhizon测渗仪收集土壤溶液。分析了土壤溶液中阳离子和阴离子的主要浓度，溶解的有机碳和pH值，并进行了离子形态分析。铜的毒性损害了南美本地草种的生长，因为铜的过量导致根系形态变化和营养失衡。在所有评估的本地物种中，Paspalum plicatulum是主要在根部吸收吸收的铜的一种，在受铜污染的土壤中具有最大的植物稳定潜力。因此，它与葡萄的间作在铜污染的土壤中可能是有益的。