Accumulation and resistance to copper of two biotypes of Cynodon dactylon.

The effects of copper accumulation and resistance in two biotypes of Cynodon dactylon were studied. Results showed that at a low concentration of copper (<100 mg/kg), the growth of Cynodon dactylon was generally unaffected. As copper concentration increased, negative effects on the growth of Cynodon dactylon became apparent. The critical concentration at which the plant exhibited poisoning symptoms was different for the two biotypes of Cynodon dactylon. At 500 mg/kg copper concentration in soil, the biotype from the polluted area showed significantly higher tolerance of copper than the biotype from the unpolluted area.

[Transformation of Cu forms in Cynodon dactylon rhizosphere soil of copper tailings yard].

The study on the Cu forms in Cynodon dactylon rhizosphere soil of copper tailings yard in Tongling City, Anhui Province showed that among the test Cu forms, the amount of residual form occupied the majority, while that of exchangeable form was relatively low. Compared with non-rhizosphere soil, rhizosphere soil had a higher organic matter content but a lower pH. With the growth of C. dactylon, the contents of organically combined and exchangeable Cu in rhizosphere soil increased by 7.89% and 5%, respectively, while those of carbonate-combined and Fe-Mn oxides-combined Cu decreased. The growth of C. dactylon accelerated the transformation of Cu forms in rhizosphere soil, and decreased the rhizosphere soil Cu content through its absorption.

[Coercion and damage of Cu pollution on Artemisia lavandulaefolia growth].

By the method of solution culture, this paper studied the coercion and damage of Cu pollution on the growth of Artemisia lavandulaefolia. The Cu concentration was set as 2.5, 5, 10, 20 and 40 mg x L(-1), experimental duration was 14 days, and the growth and physiological indices of plants were tested. The results showed that the growth of A. lavandulaefolia was stimulated at low Cu concentration (2.5 mg x L(-1)), while inhibited at higher Cu concentrations (5 to approximately 40 mg x L(-1)). There was a significant negative correlation between each growth index and Cu concentration, and pigments contents had the similar trend. The sensibility of various photosynthetic pigments to Cu was in the order of chlorophyll a > chlorophyll a + b > chlorophyll b > carotenoid. Cell membrane permeability, O2 generation rate, and MDA content decreased slightly at 2.5 mg Cu x L(- 1) and then increased with increasing Cu concentration. The activities of POD, SOD and CAT increased first but decreased then with the increasing Cu concentration, and the endurance index of root showed the same trend, being > 0.5 at the Cu concentration less than 20 mg x L(-1) while decreased to 0.36 at 40 mg Cu x L(-1).

[Heavy metals pollution of Paeonia ostii land at copper-tailings reservoir of Tongling city: a preliminary study].

The study on the soil and Paeonia ostii Cu, Cd, Pb and Zn at the copper-tailings reservoir of Tongling City, Anhui Province showed that the forms and contents of test heavy metals were differed in Paeonia ostii-planted and control soils. The Cu and Cd contents in control soil were 4.36-14.43 and 3.67-3.86 times of the 2nd national standard for soil environmental quality, respectively, and the composite pollution index of the heavy metals in Paeonia ostii-planted soil was up to 5.607. The heavy metals content in Paeonia ostii leaf and root-stem was in order of Cu>Zn>Pb>Cd, and that in Paeonia ostii stem and root- peel was Zn>Cu>Pb>Cd. The comparison of the heavy metals contents in Paeonia ostii with the criterion about herbal medicine showed that the Cu content in Paeonia ostii was 1.43-2.53 times of the criterion, and the Cd content was 1.17-3.17 times of the criterion.

[Heavy metals accumulation in different parts of Paeonia ostii and soils at copper tailings yard].

The study on the heavy metals contamination of Paeonia ostii and soil at the copper tailings yard in Tongling City indicated that the soil of copper tailings yard was extremely barren, only with 1.1-3.4 g x kg(-1) organic mater (1/15 of normal soil), but the contents of its Cu, Cd, Pb and Zn were much higher. Cu and Cd contents were 587.43-1176.44 mg x kg(-1) and 3.08-5.16 mg x kg(-1), respectively, 5-10 times higher than the grade two of national environmental quality standard for soils. Cu, Cd and Pb contents in Paeonia ostii exceeded the standard of medicine-use plants. Especially in its root peel, Cu and Cd contents stood at 31.50-64.00 mg x kg(-1) and 0.98-1.45 mg x kg(-1), respectively, 1.6-3.6 times surpassing the standard, which meant that both Paeonia ostii and the soil had been severely polluted. There existed evident difference in the contents of heavy metals in different parts of Paeonia ostii. Stem, leaf and root peel had higher contents of Zn, Cd, Pb and Cu. The accumulation factors of Zn and Cd were higher than those of Cu and Pb, but they were all smaller in root peel.