In
botany, the radicle is the first part of a
seedling
A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (emb ...
(a growing plant
embryo) to emerge from the
seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...
during the process of
germination.
The radicle is the embryonic
root of the plant, and grows downward in the soil (the shoot emerges from the
plumule
A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embryo ...
). Above the radicle is the embryonic
stem or
hypocotyl
The hypocotyl (short for "hypocotyledonous stem", meaning "below seed leaf") is the stem of a germinating seedling, found below the cotyledons (seed leaves) and above the radicle ( root).
Eudicots
As the plant embryo grows at germination, it ...
, supporting the
cotyledon
A cotyledon (; ; ; , gen. (), ) is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The numb ...
(s).
It is the embryonic root inside the seed. It is the first thing to emerge from a seed and down into the ground to allow the seed to suck up water and send out its leaves so that it can start photosynthesizing.
The radicle emerges from a seed through the
micropyle Micropyle may refer to:
* Micropyle (botany) a minute opening in the integument of an ovule of a seed plant.
* Micropyle (zoology) A micropyle is a pore in the membrane covering the ovum, through which a sperm enters.
Micropyles are also found in s ...
. Radicles in seedlings are classified into two main types. Those pointing away from the seed coat scar or
hilum are classified as ''antitropous'', and those pointing towards the hilum are ''syntropous''.
If the radicle begins to decay, the seedling undergoes pre-emergence
damping off. This disease appears on the radicle as darkened spots. Eventually, it causes death of the seedling.
The plumule is the baby shoot. It grows after the radicle.
In 1880
Charles Darwin published a book about plants he had studied,
The Power of Movement in Plants, where he mentions the radicle.
See also
*
Plant perception (physiology)
References
{{reflist
Plant anatomy
Plant morphology
Plant cognition