Title: Water and Plant Growth
Description: Mark Longstroth, Southwest Michigan District Horticultural & Marketing Agent, MSU Extension
Abstract:
I want to explain the importance of water in plants and how they grow. First, I need to review some basic plant physiology so that we are all on the same page and you can understand how I look at plants. My basic model of a plant is a leaf stuck in a straw, at the opposite end of the straw is a cotton wick, the root. That is your basic plant: leaves, stems, roots. All plant tissues consist of cells, which can be imagined as a wet cardboard box (the cell wall) with a water balloon (the plant cell) inside. The balloon itself (the cell membrane) is leaky. Water and other small molecules can move through it. This explains why the box is wet! In addition, there are proteins in the membrane that can quickly move salt ions, usually potassium, into the cell. Other proteins move sugars in and out of the cell. This allows the cell to be saltier and sweeter that the water around it. Water moves from a solution of low concentration into a higher concentration solution to dilute it. Since the cell can actively move salts into the cell, water moves into the cell as some water leaks out, and a balance between inflow and outflow occurs.