Basic Plant Biology Revision

http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/green_world/

Phloem and Xylem

Plants have two different types of transport tissue. Xylem transports water and solutes from the roots to the leaves, phloem transports food from the leaves to the rest of the plant. Transpiration is the process by which water evaporates from the leaves, which results in more water being drawn up from the roots. Plants have adaptations to reduce excessive water loss.

Xylem and phloem

Plants have transport systems to move food, water and minerals around. These systems use continuous tubes called xylem and phloem.

Xylem

Xylem vessels are involved in the movement of water through a plant from its roots to its leaves. Water:

• Is absorbed from the soil through root hair cells
• Is transported through the xylem vessels up the stem to the leaves
• Evaporates from the leaves (transpiration)

Phloem

Phloem vessels are involved in translocation. This is the movement of food substances from the stems to growing tissues and storage tissues.

Xylem and phloem - Higher tier

Diagram showing the cross sections of a xylem and a phloem

Xylem vessels consist of dead cells. They have a thick, strengthened cellulose cell wall with a hollow lumen. On the other hand, phloem consists of columns of living cells.

BBC BITESIZE

Horticultural Dictionary - Vascular

Any of various plants, such as the ferns and seed-bearing plants, in which the phloem transports sugar and the xylem transports water and salts.

Differences between Dicotyledon and Monocotyledon

Horticultural Dictionary - Angiosperm

Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies (derived characteristics). These characteristics include flowers, endosperm within the seeds, and the production of fruits that contain the seeds.

Horticultural Dictionary - Gymnosperms

Gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos, meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilized state). Their naked condition stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, often modified to form cones, or at the end of short stalks as in (Ginkgo).

Plant Kingdom