Imbibition is a special type of

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical ...

that takes place when liquid is absorbed by solids-

colloids A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others extend ...

causing an increase in volume. Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition. For a substance to imbibe a liquid, there must first be some attraction between them. Imbibition occurs when a

wetting Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. This happens in presence of a gaseous phase or another liquid phase not miscible with ...

fluid displaces a non-wetting fluid, the opposite of drainage in which a non-wetting phase displaces the wetting fluid. The two processes are governed by different mechanisms. Imbibition is also a type of diffusion since water movement is along the concentration gradient. The seeds and other such materials have almost no water hence they absorb water easily. Water potential gradient between the absorbent and liquid imbibed is essential for imbibition.

Examples

One example of imbibition in nature is the

absorption Absorption may refer to: Chemistry and biology *Absorption (biology), digestion **Absorption (small intestine) *Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials *Absorption (skin), a route by which s ...

of water by

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are n ...

. Matrix potential contributes significantly to water in such substances. Dry seeds germinate in part by imbibition. Imbibition can also control circadian rhythms in ''

Arabidopsis thaliana ''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. ''A. thaliana'' is considered a weed; it is found along the shoulders of roads and in disturbed land. A winter ...

'' and (probably) other plants. The Amott test employs imbibition. Proteins have high imbibition capacities, so proteinaceous pea seeds swell more than starchy wheat seeds. Imbibition of water increases imbibant volume, which results in imbibitional pressure (IP). The magnitude of such pressure can be demonstrated by the splitting of rocks by inserting dry wooden stalks in their crevices and soaking them in water, a technique used by early Egyptians to cleave stone blocks. Skin grafts (split thickness and full thickness) receive oxygenation and nutrition via imbibition, maintaining cellular viability until the processes of inosculation and revascularisation have re-established a new blood supply within these tissues.

Germination

Examples include the absorption of water by seeds and dry wood. If there is no pressure due to imbibition, seedlings would not be able to emerge from soil.

Radicle growth

The

radicle In botany, the radicle is the first part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil (the shoot emerges from ...

is the first part of a seedling (a growing plant

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

) 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 Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fe ...

.{{cite journal , last1=Schiltz , first1=S , last2=Gaillard , first2=I , last3=Pawlicki-Jullian , first3=N , last4=Thiombiano , first4=B , last5=Mesnard , first5=F , last6=Gontier , first6=E , title=A review: what is the spermosphere and how can it be studied? , journal=Journal of Applied Microbiology , date=December 2015 , volume=119 , issue=6 , pages=1467–81 , doi=10.1111/jam.12946 , pmid=26332271, s2cid=42515027 , doi-access=free The radicle is the embryonic

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

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 ...

) where it absorbs more water. Most part of the seed is stored energy so nutrients are not essential during the first days for the seedling.

References

Biological processes Chemical mixtures Colloidal chemistry

Examples

Germination

Radicle growth

See also

References