أكاديميا - كولنز معاجم الجيب العلمية - البيولوجيا انكليزي - فرنسي - عربي الحرف ٣_ r

Academia - Collins Scientific Pocket Dictionaries - Biology
English - French - Arabic letter 3_ R


rod. rod
bâtonnet m

hard . A nerve cell that is sensitive to light
It is found in the retina in the eye of vertebrates and can operate in weak light. See eye.


root
race f

root . Part of a flowering plant that usually grows in the soil. Its functions are:
(a) Absorption of water and mineral salts from the soil.
(b) Anchoring the plant in the soil.
(c) Food storage in some plant species, for example
Turnip.

Structure (dicot)
Longitudinal section
Transverse section


root cap
Coiffe f de race

Root cap: A cap-shaped layer of cells that covers the tip of the developing root tip and protects it as the root grows through the soil.

Longitudinal section of the root
Root cap
Root head
Structural tissue


root hairs
chevelu m

Root hairs are tubular protrusions of epidermal cells
The root, and the nucleus usually passes into the filament. Root hairs greatly increase the surface area of ​​the root, which is the plant's main absorbent tissue. Water from the soil enters the capillaries by osmosis, while mineral salts are absorbed by active transport. Then water and mineral salts pass through the cortex and enter the xylem vessels, and from there they are transported to all parts of the plant via the transpiration stream.


root nodes
Nodules mpl de race

Root nodules. Swellings on the roots of leguminous plants (such as clover, beans, and peas). The root nodules contain spores of the genus Rhizobium genus that convert nitrogen present in the soil air into organic nitrogen compounds that the pods can use. This is called nitrogen fixation. Wait for nitrogen cycle.


roughage
The matières fpl inasimilables

Roughs are an important component of a balanced human diet and consist mainly of cellulose found in plant cell walls. Although humans cannot digest coarse food, this food adds mass to the food and enables the muscles of the alimentary canal to hold the food.
It is constantly moved by peristalsis.