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Terms in this set (107)

Triple Response mechanism: For example, if we were talking about ethylene which is produced when a seedling tip pushes against an obstacle, the production of ethylene induces a triple response which causes the stem elongation to be slowed and the stem thickens and grow horizontally. When the ethylene wears, off then the plant will resume in growing vertically.
Apoplastic and Symplastic routes: These are the two main ways of water transport in plants. When looking at apoplastic routes, water and minerals move up the stem in the apoplast. It goes from the root hair to the xylem. It is made up of more nonliving components which is why this way of transport is least affected by the state of the plant. Syplastic routes on the other hand have to do with a pathway of ions and water which is created by the symplast. Symplatic routes have to do with living components and tend to be slower in comparison. The metabolic state has a impact on the flow of water since it does have living components.
Acid growth hypothesis: This hypothesis is a theory that explains the expansion dynamics of cells and organs in plants. The naturally ocurring plant hormone auxin, (AAI) that we studied this last chapter produces a H+ proton in the apoplast. It has been studied a lot and the molecular mechanisms and effects of auxin have been thoroughly researched. Auxin stimulates proton pumps in the plasma membrane. Proton pumps then move H+ into the cell which lowers the pH in the cell wall. This lowering of pH activates expansions which loosens the fabric of the cell wall. An osmotic uptake of water then increases the turgor pressure which enables the cell wall to elogate.