Some plant species can take up heavy metal contaminants that are dissolved in soil water and then transport them within the plant. Within plant cells, the heavy metals accumulate mainly in the vacuole. Which suggestions about the transport and accumulation of heavy metals are valid? 1 After initial entry into the root, some of the heavy metals can pass through the tonoplast to be stored in the vacuole of cells in the cortex. 2 The heavy metals take an apoplastic pathway in the xylem but at the endodermis must take a symplastic pathway. 3 The rate of accumulation of the heavy metals in leaf cells will be faster at night, when photosynthesis is not occurring, than during the day. 4 The presence of heavy metals causes the transpiration stream to slow down and reduce the rate of transpiration.