Transpiration - Water Movement through Plants Glossary

A region of still air near the surface of a leaf through which water must diffuse en route to the atmosphere.

A polysaccharide of glucose units that constitutes the chief part of the cell walls of plants.

A transport protein in the membrane of cells that are selective pores, through which molecules can diffuse across the membrane.

An organelle within the plant cell in which the photosynthetic reactions are compartmentalized. The thylakoid membranes within the chloroplast are the site of the photosynthetic pigments and electron transfer components used to make energy from photosynthesis. The non-membrane space within the chloroplast is called the stroma; this is where photosynthetic energy is used to convert CO₂ into sugars.

Able to stick together tightly.

A channel through which something (as a fluid) is conveyed.

The tissue in roots and stems lying between the epidermis and the vascular tissues.

To convert from a liquid to a vapor.

The positive pressure built up when water is compressed.

The complex phenolic polymer that endows the xylem and other tissues in plants with compression and decay resistance.

The conversion of light energy into chemical energy by plants using low-energy inorganic compounds (carbon dioxide) to produce high-energy organic compounds (sugars)

The semi-permeable membrane that surrounds the protoplasm of a cell.

An essential plant nutrient needed in large amounts.  Postassium is vital to plant nutrient absorption, respiration, transpiration and enzyme activity. The major portion of potassium is contained in minerals such as feldspar and mica, and clays such as montmorillonite, vermiculite and illite.

Special proteins in the cell membrane that bind to a signal or chemical messenger from the environment and transmit signals to the cell to initiate a response.

The ability of an organism to survive and thrive in the presence of something that would normally cause damage or death, i.e., herbicide-resistant corn, Roundup-ready corn.

An opening in the outer layer cells in a leaf bordered by two guard cells and serving in gas exchange.

One of the two major types of water-conducting cells found in plants (vessel elements are the others). The elongate cells are dead at maturity, have tapered ends and are arranged end to end and have walls that are partially coated with lignin.

The loss of water as vapor from plants at their surfaces, primarily through stomata.

Vessels, or vessel elements, are one of the two major types of water-conducting cells found in plants (tracheids are the others). The elongate cells are dead at maturity, have tapered ends and are arranged end to end and have walls that are partially coated with lignin

The chemical potential of water; a measure of the ability of a substance to absorb or release water relative to another substance.

Nonliving cells connected end to end to form a series of long, thin tubes from root to the shoot, used to supply cells with water and nutrients that are dissolved in water.