transport in plants

• why do plants need transport systems?

  Plants need water, minerals and sugars to live- they also need to move waste substances too. Because plants are multicellular, they have a small surface area : volume ratio and also due to their size have a high metabolic rate. Thus exchanging substances via regular diffusion would be too slow, hence transplant systems are used.
• where are xylem vessels found?

  in the roots, the xylem are found in the centre for support for the soil as they push through the soil. In the stem, the xylem are near the outside to provide some scaffolding to reduce bending.
• Where are phloem vessels found?

  In the stems, the phloem vessels are found outside to provide scaffolding in order to reduce bending. In the roots they are found in the middle to provide support for the root as they push through the soil.