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 are valid suggestions about the transport and accumulation of heavy metals?

1 After initial entry into the root, some of the heavy metals can pass through the tonoplast to be stored in the vacuole of cortical cells.

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 the heavy metal will inhibit active transport, causing the transpiration stream to slow down and reduce the rate of transpiration.