Laimosphere

The combining form laim- from laimos (Greek: λαιμός, "throat") denotes a connecting organ (neck) while -sphere indicates a zone of influence.

Topographically, the laimosphere includes the soil around any portion of subterranean plant organs other than roots where exuded nutrients (especially sugars and amino acids) stimulate microbial activities.

Subterranean plant organs with a laimosphere include hypocotyls, epicotyls, stems, stolons, corms, bulbs, and leaves.

For instance, microbial communities in the laimosphere are distinct from those in the phyllosphere (the plant's aerial surfaces), with specific taxa adapted to the soil's unique moisture and nutrient availability.

The microbes in the laimosphere play important roles, such as helping the plant absorb nutrients and protect against stressors like drought or salinity.

Fig. 1. A diagram denoting the location of the laimosphere, rhizosphere, and spermosphere of the subterranean organs of a plant ( Plant and Soil 37:187-190, 1972).

Fig. 2. Chlamydospores of Fusarium solani f. sp. cucurbitae forming in the laimosphere of a squash hypocotyl, Magyarosy 1973.

Fig. 3 & 4. Early lesion development in the epidermis of a squash hypocotyl caused by Fusarium solani stained with tetrazolium salt, Magyarosy 1973.

Fig. 5. Diagram of hypocotyl stem rot leading to "damping-off" caused by Rhizoctonia solani (Univ.Calif. Agr. Exp. Sta. Service Manual 23, 1957).