Sclerenchyma Cells are short-lived with thick cell walls. Serves to support the plant. The outer layer of cells. Protects the plant and reduces water loss. Stomata Regulate gases passing into and out of the plant Usually located on the under side of leaves.
Guard cells regulate the opening by changing water pressure within the cell to swell or shrink.
A tree behaves like a big straw, as water moves out of the leaves at the top and water moves in at the roots to replace it. Water has been measured traveling up the stems of some oak trees at a rate of 60 meters per hour. Apical meristem - located at the tips of stems and roots, this meristem produces growth in length known as primary growth . Lateral meristem - located around the outer edge of stems and roots, this meristem produces growth in circumference known as secondary growth . Cork cambium - located outside the phloem, it produces the cork.