Phytoremediation potential of moso bamboo (Phyllostachys pubescens) for zinc and ultrastructure changes under zinc toxicity
This study has investigated toxicity of Zn and phytoremediation ability in shoot of moso bamboo. In hydroponic experiment the plants showed high Zn torelence up to application of 400 µM, while there was a general trend of decline in the roots and shoot biomass. Maximum concentration of 1594 mg kg–1 was observed in shoot after treating with 100 µM Zn. The shoot/root ratio reached the level of 0.27 under 10 µM zinc stress. Transmission electron microscopy revealed that electron-dense granules in vacuoles and structure of leaf cells were significantly effected by 200 µM of Zn. However, mitochondria and thylakoid membrane arrangement did not alter. Using scanning electron microscopy, Zn-related changes in the structure of the stoma were uncovered and crystal particles probably of Zinc were observed in stem.
Studies on Soil Microbial Activity in Areas Contaminated by Tailings from Pb,Zn Mine
Based on field investigation and sample analysis of polluted soil from Pb,Zn mine in Quzhou county Zhejiang province,microbial activities,soil enzymes activities and heavy metal accumulation in plants were studied.The results showed average value of Pb,Zn,Cd,Cu content in polluted areas were 267.8,132.6,41.8 and 17.0 times of the non-mine soil.Heavy metal concentration in plants was positively correlated with total and available heavy metal concentration in soils.The microbial biomass carbon decreased,whereas basal respiration and qCO_2 increased with increasing of heavy metal concentration.The microbial biomass carbon in mine center soil was 72% of control,but basal respiration and qCO_2 was 1.6 and 2.3 fold respectively.Each kind of soil enzyme activities was higher than that of the mined soil,among which dehydrogenase activity changed most remarkably,so it can be a better index in evaluation of heavy metal pollution in mine area.
Trouble-shooting dual arch impressions.
Dual arch impression techniques enable the dentist to capture an impression of the prepared tooth, the opposing teeth and the occlusal registration in one procedure. This saves chair time and impression material.