ETYM as. plante, Latin planta.
1. An actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience.
2. Buildings for carrying on industrial labor; SYN. works, industrial plant.
3. Something or someone used secretly for discovery by another.
A living vegetal organism; SYN. flora, plant life.
Organism that carries out photosynthesis, has cellulose cell walls and complex cells, and is immobile. A few parasitic plants have lost the ability to photosynthesize but are still considered to be plants.
Plants are autotrophs, that is, they make carbohydrates from water and carbon dioxide, and are the primary producers in all food chains, so that all animal life is dependent on them. They play a vital part in the carbon cycle, removing carbon dioxide from the atmosphere and generating oxygen. The study of plants is known as botany.
Levels of complexity
Many of the lower plants (the algae and bryophytes) consist of a simple body, or thallus, on which the organs of reproduction are borne. Simplest of all are the threadlike algae, for example Spirogyra, which consist of a chain of cells.
The seaweeds (algae) and mosses and liverworts (bryophytes) represent a further development, with simple, multicellular bodies that have specially modified areas in which the reproductive organs are carried. Higher in the morphological scale are the ferns, club mosses, and horsetails (pteridophytes). Ferns produce leaflike fronds bearing sporangia on their undersurface in which the spores are carried. The spores are freed and germinate to produce small independent bodies carrying the sexual organs; thus the fern, like other pteridophytes and some seaweeds, has two quite separate generations in its life cycle (see alternation of generations).
The pteridophytes have special supportive water-conducting tissues, which identify them as vascular plants, a group which includes all seed plants, that is the gymnosperms (conifers, yews, cycads, and ginkgos) and the angiosperms (flowering plants).
The seed plants are the largest group, and structurally the most complex. They are usually divided into three parts: root, stem, and leaves. Stems grow above or below ground. Their cellular structure is designed to carry water and salts from the roots to the leaves in the xylem, and sugars from the leaves to the roots in the phloem. The leaves manufacture the food of the plant by means of photosynthesis, which occurs in the chloroplasts they contain. Flowers and cones are modified leaves arranged in groups, enclosing the reproductive organs from which the fruits and seeds result.
The earliest fossil evidence of land plants comes from spores, resembling the spores of some lower plants, found in rocks that may be up to 470 million years old.
Cooksonia pertoni, a tiny fossil plant only a few centimeters high and 400 million years old, is considered to be the ancestor of all higher (vascular) plants. Fossil evidence found in Shropshire, England, demonstrates many features critical to higher plants, most notably small strengthened tubes which allowed the plants to support themselves, grow upright, and transport water to the cells at the top of the their branches.
1. To implant in the mind; SYN. implant.
2. To place into a river
3. To put or set (seeds or seedlings) into the ground; SYN. set.