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stem

(Encyclopedia)stem, supporting structure of a plant, serving also to conduct and to store food materials. The stems of herbaceous and of woody plants differ: those of herbaceous plants are usually green and pliant ...

brain stem

(Encyclopedia)brain stem, lower part of the brain, adjoining and structurally continuous with the spinal cord. The upper segment of the human brain stem, the pons, contains nerve fibers that connect the two halves ...

stem cells

(Encyclopedia)stem cells, unspecialized human or animal cells that can produce mature specialized body cells and at the same time replicate themselves. Embryonic stem cells are derived from a blastocyst (the blastu...

pith

(Encyclopedia)pith, in botany, core of the stem of most plants. Pith is composed of large, loosely packed food-storage cells. As the stem grows older the pith usually dries out, and in some it disintegrates and the...

tuber

(Encyclopedia)tuber, enlarged tip of a rhizome (underground stem) that stores food. Although much modified in structure, the tuber contains all the usual stem parts—bark, wood, pith, nodes, and internodes. The ey...

Gurdon, Sir John Bertrand

(Encyclopedia)Gurdon, Sir John Bertrand, 1933–, British biologist, Ph.D. Oxford, 1962. He has been a researcher at Cambridge since 1971. Gurdon was the joint recipient of the 2012 Nobel Prize in Physiology or Med...

meristem

(Encyclopedia)meristem mĕrˈistĕmˌ [key], a specialized section of plant tissue characterized by cell division and growth. Much of the mature plant's growth is provided by meristems. Apical meristems found at th...

phloem

(Encyclopedia)phloem flōˈĕm [key]: see bark; stem. ...

xylem

(Encyclopedia)xylem zīˈləm [key]: see stem; wood. ...

note, in music

(Encyclopedia)note, in musical notation, symbol placed on or between the lines of a staff to indicate the pitch and the relative duration of the tone to be produced by voice or instrument. The largest note value in...