Cadmium (Cd) and arsenic (As) exist simultaneously in soil environment, which poses a serious threat to the safety of agricultural products and forage production. Four Perennial Ryegrass (Lolium perenne L.) cultivars with different accumulation characteristics (ʻNicaraguaʼ, ʻVenusʼ, ʻExcellentʼ and ʻMonroʼ) were selected as the material for pot experiment. The coupled responses of key components and related enzyme activities under combined stresses of Cd and As were investigated. key components contents include Non protein sulfhydryl (NPT), glutathione (GSH) and phytochelatins (PCs). The related enzyme includes (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), γ-glutamylcysteine synthetase (γ-ECS), glutathione synthetase (GSS), phytochelatin synthetases (PCSase) and arsenate reductase (AR). The results showed that Cd contents of perennial ryegrass were higher than those of As contents with TFCd/As < 1. Cd and As contents in roots were in the higher proportion than those in shoots. Compared to control, POD activities increased by 2.72 folds under 120 mg kg−1 As treatment. The contents of PCs increased by 5.68 folds under 120 mg kg−1 As treatment. Under combined Cd and As stress, the MDA contents and antioxidant enzyme activities of ʻVenusʼ were higher than those of ʻNicaraguaʼ. ʻNicaraguaʼ, a high accumulation cultivar. Under the combined stresses of Cd and As, the enzyme activities and the key components were significantly correlated (P < 0.05) with the contents of Cd and As. The tolerance to Cd and As was improved with increase in GSH and PCs contents and γ-ECS, GSS, PCSase and AR activities. In conclusion, the antioxidant enzyme system and key resistant substances of perennial ryegrass have important and antagonistic effects on Cd and As stresses.

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In order to screen out the plants used to repair heavy metal pollution in the soil, five plants and surface soil were collected in the Huize lead-zinc mine area, centered on the hyperaccumulator plant Arabis alpina L. var. parviflora Franch, measured the heavy metal content of in shoot and root of plant and surface soil, and analyzed the characteristics of heavy metal accumulation in plants. The results showed that the soil Cd pollution in the Huize lead-zinc mining area was the most serious; among the five plants, the Cd bioconcentration factor(BCF) and translocation factor(TF) of A. alpina were more than 1, and the TF of Pb was more than 1; the TF of Anaphalis margaritacea, Cyananthus inflatus and Arenaria orbiculata to Cu and Zn were more than 1, the TF of Juncus effusus to Cd and Zn were more than 1. These five plants had good tolerance to heavy metals and were of great significance to the remediation and restoration of heavy metal contaminated soil in lead-zinc mining areas.

A field experiment was carried out in a farmland polluted by cadmium (Cd) and arsenic (As) in Yunnan Province to study Cd and As accumulation characteristics of 15 different forage plants, so as to screen out plants for comprehensive utilization in the farmland polluted by Cd and As. The results showed that the best growth conditions were for ‘Teosinte’ and ‘King grass’, the worst growth condition was ‘Pennisetum’. The Cd contents of shoots of ‘King grass’, ‘Sweet elephant grass’, ‘Pennisetum’, ‘Teosinte’ and ‘Alfalfa’ did not exceed the Chinese feed hygiene standard (≤ 1mg kg−1). The content of total arsenic in shoot of ‘Tall fescue’ did not exceed the feed hygienic standard (≤ 4 mg kg−1). ‘Sorghum12FS9003’ and ‘Sorghum×Sudan’ have the strongest ability to enrich Cd and As, which could be used for remediation of soil polluted by Cd and As. ‘Alfalfa’ has low Cd and As accumulation capacity.

To explore the effects of Cd and As composite contaminated soils on the element contents and effectiveness in rhizosphere soils of different forages, the root morphology, rhizosphere soil elements and their availability of 21 forages were studied and analyzed. The results showed: The 21 cultivars showed significant differences in root morphological characteristics. Root length is an index of root morphology that has the highest correlation with other elements and availability. And the correlation between the availability of each element and root morphology was higher than that of element content. Among them, Fe availability was significantly correlated with root morphological characteristics (P<0.05). The contents of different elements and availability varied greatly among the different cultivars. Among the six rhizosphere soil elements, the difference of toxic metal Cd was the largest, while the difference of Al availability was the largest. According to the correlation analysis between the elements and availability of each cultivar, the interaction of the availability of each element is higher than that of the soil element under the composite contaminated of Cd and As. Toxic metals Cd and As affected each other, and there was a very significant positive correlation between the content and availability. Fe, Mn and P had higher correlation with Cd and As.