translocation


Значение термина translocation в knolik


translocation - translocation
translocation - (1) (Bot.). Transport of materials within plant. (a) Absorption of minerals from soil by roots and movement upwards in xylem to growing points, leaves. Absorption is under metabolic control, often taking place against a concentration gradient. In xylem minerals are carried upwards in transpiration stream but while rate of movement is influenced by rate of transpiration this relationship is not a consistent one. Some mineral ions are converted into organic substances and carried upwards in this form, (b) Movement of synthesized organic materials, sugars, nitrogenous compounds, and in addition, some inorganic ions, upwards and downwards in phloem, from leaves to regions of active growth and of storage, pattern of translocation changing during development, with changing needs in different parts of plant. Rate of movement of material in phloem is often very high, 100 cm. per hour or more, far faster than would be possible by simple diffusion; i.e. it is under metabolic control though precise mechanism of process is not yet resolved. (2) (Genetics). Transfer of part of a chromosome into a different part of a homologous, or into a non-homologous, chromosome. See also: Mutation.

Рядом со словом translocation в knolik


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transmitter

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