| OAR | organ at risk |
|---|---|
| OBF | organ blood flow |
| OC | obstetrical conjugate; occlusocervical; office call; on call; only child; optic chiasma; oral contra... |
| OPO | Organ Procurement Organization |
| OS | left eye [Lat. oculus sinister]; occipitosacral; occupational safety; office surgery; Omenn syndrome... |
| plant root cap | A cone-shaped structure in plants made up of a mass of meristematic cells that covers and protects the tip of a growing root. It is the putative site of gravity sensing in plant roots. (12 Dec 1998) |
|---|---|
| plant roots | The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (12 Dec 1998) |
| plant shoots | The aerial portions of a plant, including stem, branches, and leaves and also, new immature growth on a plant. (12 Dec 1998) |
| plant stems | Parts of plants that usually grow vertically upwards towards the light and support the leaves, buds, and reproductive structures. (12 Dec 1998) |
| plant succession | <botany> The development of a plant community from its initial stage to its climax stage. (31 Dec 1997) |
| plant toxin | A substance similar in its properties to an extracellular bacterial toxin. Synonym: plant toxin. Origin: phyto-+ G. Toxikon, poison (05 Mar 2000) |
| plant transpiration | The loss of water vapor by plants to the atmosphere. It occurs mainly from the leaves through pores (stomata) whose primary function is gas exchange. The water is replaced by a continuous column of water moving upwards from the roots within the xylem vessels. (12 Dec 1998) |
| plant tumours | A localised proliferation of plant tissue forming a swelling or outgrowth, commonly with a characteristic shape and unlike any organ of the normal plant. Plant tumours or galls usually form in response to the action of a pathogen or a pest. (12 Dec 1998) |
| plant viruses | Viruses parasitic on plants higher than bacteria. (12 Dec 1998) |
| wind-plant | <botany> A windflower. Source: Websters Dictionary (01 Mar 1998) |
| short-day plant | A plant requiring less than 12 hours of daylight in order for flowering to occur. (09 Oct 1997) |
| submersed plant | Plants growing with their root, stems, and leaves completely under the surface of the water. (09 Oct 1997) |
| day neutral plant | <botany> Plants that flower regardless of day length. (09 Oct 1997) |
| DNA, plant | Deoxyribonucleic acid that makes up the genetic material of plants. (12 Dec 1998) |
| dove plant | <botany> A Central American orchid (Peristeria elata), having a flower stem five or six feet high, with numerous globose white fragrant flowers. The column in the center of the flower resembles a dove. Synonym: Holy Spirit plant. Source: Websters Dictionary (01 Mar 1998) |