Plant tissues and transport

The idea

Leaf tissues include the epidermis, palisade mesophyll (most photosynthesis) and spongy mesophyll (air spaces for gas exchange). Xylem carries water and mineral ions from roots to leaves; phloem carries dissolved sugars around the plant (translocation). Transpiration is the loss of water vapour from leaves: water evaporates inside the leaf and the vapour diffuses out through stomata, whose size is controlled by guard cells. It is faster when it is hot, dry, windy or bright.

1. Name the tissue and its job.
2. Separate xylem (water, one way) from phloem (sugars, both ways).
3. Link each factor to its effect on transpiration.

Watch out Xylem carries water up only; phloem carries sugars both up and down.