Today when giving my babies a little drink, I began to think about how they got that water from the dirt up to their leaves. They don't have a mouth or anything so how does that happen? Well, plants absorb nutrients and water from the soil through their roots, and their vascular tissues called the xylem transports it up to the leaves. The xylem is able to do this because it is made of long, tracheary elements that specialize in transporting water. It is also composed of parenchyma and fibres. The soil composition is very important to a plant because it provides all necessary nutrients, like nitrogen, a plant needs to grow healthy and without that it could die. A plants phloem, another vascular tissue, transports sugar molecules, amino acids, and hormones both up and down through the plant. Transpiration is leaf evaporation of water through small openings in the plant wall called stomata. Stomata are bordered by guard cells which open and close it to release water evaporation, or keep it in. Turgor pressure is what pushes the plasma membrane against the cell wall of plant cells. Turgidity is caused by the flow of water from an area of low solute concentration outside of the cell into the cell, which has a higher solute concentration. Healthy plant cells are turgid and plants rely on turgidity to maintain structure against the elements. The casparian strip is another important part in water delivery throughout a plant. Casparian strips are waterproof bands which run around the cell wall of endodermal cells in plant roots. Their purpose is to force water which has been following the apoplastic pathway, into the living protoplast of the endodermal cell. Mineral ions in the water are actively transported into the xylem, meaning the xylem now has a lower water potential than the endodermal cell, causing the water to move into the xylem through osmosis.
