Species: Arabidopsis thaliana Common Name: thale cress Taxonomy: Brassicales; Brassicaceae; Arabidopsis Trichome Image
Description of Trichomes:
Simple non-glandular trichomes (ST).

The Arabidopsis trichomes develop from isodiametric protodermal cells, which are large, single epidermal cells with a stalk and three or four branches on the surface of most shoot-derived organs.
Publications: 9177205 8313475 1843415 10785667


Species: Artemisia annua Common Name: sweet wormwood Taxonomy: Asteroideae; Anthemideae; Artemisia
Description of Trichomes:
Glandular secreting trichomes (GST).

A. annua glandular trichomes are 10-celled biseriate. Three apical cell pairs represent the secretory head, the first two top hairs contain amoeboid plastids without thylakoid, whereas in the two cell pairs below, ameboid chloroplasts show the presence of photosynthetic thylakoids. Stalk cell plastids containing starch grains and thylakoids were occasionally present in basal cell.

In A. annua GSTs, the sesquiterpene lactone artemisinin accumulates to levels of 0.01-2% dry weight.

Reference:
1) Duke SO, Paul RN (1993) Development and fine structure of glandular trichomes of Artemisia annua L.. Int. J. Plant Sci. 154: 107-118.
2) Wagner GJ, Wang E, Shepherd RW. New approaches for studying and exploiting an old protuberance, the plant trichome. Ann Bot (Lond). 2004 Jan;93(1):3-11.
3) Mary V. Duke, Rex N. Paul, Hala N. Elsohly, George Sturtz and Stephen O. Duke. Localization of Artemisinin and Artemisitene in Foliar Tissues of Glanded and Glandless Biotypes of Artemisia annua L. International Journal of Plant Sciences. Vol. 155, No. 3 (May, 1994), pp. 365-372
Publications: 14678941 18203058 17399751 16579958 16557475 16458889 15678372 17345348 18495659 INTERNAL-1


Species: Cannabis sativa Common Name: hemp Taxonomy: Rosales; Cannabaceae; Cannabis
Description of Trichomes:
Publications: 19581347


Species: Cistus creticus Common Name: Taxonomy: Malvales; Cistaceae; Cistus
Description of Trichomes:
Glandular secreting trichomes (GST); non glandular simple trichomes (NGT).

Cistus creticus leaf trichomes consist of non glandular (stellate) and glandular, long, ball-headed, multi-cellular trichomes. Glandular trichomes are composed of a long multi-cellular stalk of over 200 micrometer toped by a small glandular head cell, In addition, two types of non-glandular trichome are present, multi-cellular stellate and simple unicellular spikes.

The resin excreted from these glands was known and used since ancient times for its officinal and aromatic properties. These traditional applications were corroborated by recent findings showing that the resin's labdane-type components such as ent-3'-acetoxy-13-epi-manoyl oxide, ent-13-epi-manoyl oxide, (13E)-labd-13-ene-8a,15-diol, (13E)-labd-7,13-diene-15-ol, (13E)-labd-7,13-diene-15-yl acetate, (13E)-labd-7,13-dienol, sclareol [(13R)-labd-14-ene-8,13-diol] or manoyl oxide derivatives, in free form or incorporated in liposomes, exhibited strong in vitro cytotoxic and cytostatic activity against human cancer lines.

Reference:
1) Irene Paterakia and Angelos K. Kanellis (2008) Isolation and functional analysis of two Cistus creticus cDNAs encoding geranylgeranyl diphosphate synthase. doi:10.1016/ j.phytochem.2008.02.005
2) Gulz et al., 1996 P.G. Gulz, T. Herrmann and K. Hangst, Leaf trichomes in the genus Cistus, Flora 191 (1996), pp. 82-104.
3) Falara V, Fotopoulos V, Margaritis T, Anastasaki T, Pateraki I, Bosabalidis AM, Kafetzopoulos D, Demetzos C, Pichersky E, Kanellis AK. (2008) Transcriptome analysis approaches for the isolation of trichome-specific genes from the medicinal plant Cistus creticus subsp. creticus. Plant Mol Biol. 2008 Dec;68(6):633-51. Epub 2008 Sep 26.
Publications: 18402992 18819010


Species: Humulus lupulus Common Name: common hop Taxonomy: Rosales; Cannabaceae; Humulus Trichome Image
Description of Trichomes:
Glandular trichomes (peltate and bulbous); non-glandular trichomes (cystolith hairs).

Leaves of Humulus lupulus possess two types of glandular trichomes: peltate (lupulin) and bulbous. Peltate trichomes are built of a glandular head consisting of 30 to 72 cells, four stalk cells and four basal cells. The glandular head consists of a multi-cellular ring of cells that forms a cup-like structure that fills with a yellow resin containing large amounts of xanthohumol and other terpenophenolics. Bulbous trichomes consist of four (occasionally eight) head glandular cells, two stalk cells and two basal cells. The glandular trichomes in Humulus lupulus form at the base of the abaxial surface of bract-like leaves surrounding the female flower.

Leaves of Humulus lupulus also possess non-glandular trichomes -- cystolith hairs, which is a hard calcium carbonate structure at base of a hair.

Essential oil includes Myrcene, humulene and caryophyllene; bitter acids includes humulones and lupulones; prenylfalvonoids includes Xanthohumol and desmethylxanthohumol.

Reference:
1) Jana Nagel, et al. (2008) EST analysis of hop glandular trichomes identifies an O-Methyltransferase that catalyzes the biosynthesis of xanthohumol. The Plant Cell 20:186-200.
2) M. Margarida Oliveira, M. Salomk S. Pais. (2008) Glandular trichomes of Humulus lupulus var. Brewer's Gold: Ontogeny and histochemical characterization of the secretion. Nordic Journal of Botany. 8(4): 349-359.
Publications: 18223037 18775972 INTERNAL-3


Species: Medicago sativa Common Name: alfalfa Taxonomy: Papilionoideae; Trifolieae; Medicago Trichome Image
Description of Trichomes:
Haired glandular secreting trichomes (GST); haired non-glandular trichomes.

Insect leafhopper resistant variety of alfalfa contains high densities of erect glandular trichomes containing multicellular stalks typically over 200 micrometer long toped by a glandular heads composed of a few cells with a diameter of approximately 15 micrometer. In potato, leafhopper resistance has been associated with certain varieties, such as G98A, that contain these trichomes. The fatty amide N-(3-methylbutyl)amide of linoleic acid has been associated with insect leafhopper resistance ( Ranger et al. Phytochem. 66:529-541).

Alfalfa also exhibits a second type of glandular trichome of unknown function similar to that shown for M. truncatula.

Alfalfa has non-glandular trichome as well, composed of a short base cell and a unicellular elongated shaft.

Reference
1) Christopher M. Ranger, Arthur A. Howerb. (2001) Glandular Morphology from a Perennial Alfalfa Clone Resistant to the Potato Leafhopper. Crop Science 41:1427-1434.
2) Ranger CM, Winter RE, Rottinghaus GE, Backus EA, Johnson DW. (2005) Mass spectral characterization of fatty acid amides from alfalfa trichomes and their deterrence against the potato leafhopper. Phytochemistry. Mar;66(5):529-41.
Publications: 16686157 15721945 15609831 15578217 15274440 12020025 11561857 8704126


Species: Medicago truncatula Common Name: barrel medic Taxonomy: Papilionoideae; Trifolieae; Medicago Trichome Image
Description of Trichomes:
Glandular secreting trichomes (GST); non-glandular trichomes.
Publications: 15578217 12164805


Species: Mentha x piperita Common Name: peppermint Taxonomy: Nepetoideae; Mentheae; Mentha
Description of Trichomes:
Peltate glandular secreting trichomes (GST).

In mint, peltate glandular trichomes are the most important trichome type. They consist of a basal cell, a stalk cell, and disc of 8 glandular cells approximately 60 micrometer in diameter. The gland cells secrete essential oils consisting of largely p-menthanes monoterpenes that include menthone and menthol, into an elevated cavity covered by a waxy cuticle.

Reference
1) David McCaskill, Jonathan Gershenzon and Rodney Croteau.(1992) Morphology and monoterpene biosynthetic capabilities of secretory cell clusters isolated from glandular trichomes of peppermint (Mentha piperita L.). Planta 187:445-454.
Publications: 16292524 15542490 11587585 11027716 11027715 10717007 10631265 10570138 10398724 1444454 1605644 1559995 16014363 15003417 17268996


Species: Nicotiana benthamiana Common Name: Taxonomy: Nicotianoideae; Nicotianeae; Nicotiana
Description of Trichomes:
Glandular secreting trichomes (GST).
Publications: 15807779 12687369 10355755 8704126 18931142


Species: Nicotiana tabacum Common Name: common tobacco Taxonomy: Nicotianoideae; Nicotianeae; Nicotiana
Description of Trichomes:
Peltate glandular secreting trichomes (GST).

Tobacoo leaf trichomes are glandular and there are two different types. Both are tall trichome (multicellular stalk, unicellular or multicellular head) and the short trichome (unicellular stalk, multicellular head) exhibit characteristics common to gland cells --- a dense cytoplasm, numerous mitochondria, and little vacuolation. The tall trichome contains structurally well developed chloroplasts and an elaborate network of endoplasmic reticulum. The short trichome contains undifferentiated plastids and endoplasmic reticulum which parallels the nucleus and plasmalemma. Few dictyosomes are seen either in the short trichome or in the tall trichome. The short trichome appears to undergo structural changes concurrently with the appearance of secretory product within the cells.

Tobacco glandular trichomes exude labdene-diol diterpenes and amphipathic sugar esters.

Reference
1) Carolyn P. Akers, J.A. Weybrew, and R.C. Long. (1978) Ultrastructure of glandular trichomes of leaves of Nicotiana Tabacum L., cv Xanthi. Amer. J. Bot. 65(3): 282-292.
2) Lin Y, Wagner GJ. 1994. Rapid and simple method for estimation of sugar esters. Journal of Agriculture and Food Chemistry 42: 1709-1712.
Publications: 17965274 17573541 17006798 16926166 16731580 16455356 15894716 12569411 12177128 11523655 9895315 9484446 8311442 1465611 16667871 16664523 18711121


Species: Ocimum basilicum Common Name: sweet basil Taxonomy: Nepetoideae; Ocimeae; Ocimum
Description of Trichomes:
Peltate glandular secreting trichomes (GST).

The large peltate glandular trichomes are the most important trichome type. These trichomes consist of a base cell, stalk cell, and a 4 celled head (Werker et al. Annals of Bot 71:43-50). The four cells form a disc and essential oils and other compounds into an elevated head space covered by a waxy cuticle. The major secondary metabolites that accumulate are basil line specific. For example, the SW line accumulates large amounts of the phenylpropanoid eugenol and the monoterpanoid linalool, while these volatiles are not found in the MC line where the phenylpropanoid mehylcinnanmate is dominant (Xie et al., Plant J 54:349).

Basil leaves also exhibit a smaller capitate glandular trichome consisting of a single base and stock cell and one to two celled head. Multicellular non-glandular spiked trichomes are often found on the mid vein.

Reference
1) Werker E, Putievsky E, Ravid U, Dudai N. and Katzir I. (1993) Glandular Hairs and Essential Oil in Developing Leaves of Ocimum basilicum L. (Lamiaceae). Annals of Botany 71: 43-50.
2) Xie Z, Kapteyn J, Gang DR. (2008) A systems biology investigation of the MEP/terpenoid and shikimate/phenylpropanoid pathways points to multiple levels of metabolic control in sweet basil glandular trichomes. Plant J. 54:349-361.
Publications: 18248593 17951447 16896796 16782809 15516500 14657409 12428018 12324268 11161012 18987218 11884690


Species: Salvia fruticosa Common Name: sage Taxonomy: Nepetoideae; Mentheae; Salvia
Description of Trichomes:
Glandular secreting trichomes (GST).

Three different types of capitate hairs were found in S. fruticosa. Type I, consisting of 1-2 stalk cells and 1-2 enlarged, rounded to pear-shaped secretory head cells; Type II, consisting of 1-2 stalk cells and one elongated head cell as narrow as the stalk cells at its base and slightly enlarged above; Type III, consisting of 2-5 elongated stalk cells and rounded head in young leaves, which will becomes cup-shaped in mature leaves.

Reference
1) Werker E, Ravid U, Putievsky E. 1985. Structure of glandular hairs and identification of the main components of their secreted material in some species of the Labiatae. Israel Journal of Botany 34: 31-45
2) Serrato-valenti G, Bisio A, Cornara L and Ciarallo G. (1997) Structural and Histochemical Investigation of the Glandular Trichomes of Salvia aurea L. Leaves, and Chemical Analysis of the Essential Oil. Annals of Botany 79: 329-336.
Publications:


Species: Solanum arcanum Common Name: Taxonomy: Solaneae; Solanum; Lycopersicon
Description of Trichomes:
Publications:


Species: Solanum habrochaites Common Name: wild tomato Taxonomy: Solaneae; Solanum; Lycopersicon
Description of Trichomes:
Glandular secreting trichomes (GST).

Five kinds of glandular trichomes have been found in tomato species, which are Type I, large with multicelluar base; Type III, intermediate in size with a single basal cell; Type V, short, slender, 1-4 celled; Type VI, short with a 2-4 celled glandular head and Type VII, 0.05-0.1 mm smaller glandular hairs with a 4-8 celled glandular head (Reeves 1977).

Type VI trichomes are particularly abundant on the leaves and stems of the cultivated species Solanum lycopersicum (formerly Lycopersicon esculentum) and its wild relative Solanum habrochaites (formerly Lycopersicon hirsutum) f. typicum LA1777 (Gianfagna et al., 1992). They have been shown to accumulate monoterpenes in S. lycopersicum and very high levels of sesquiterpenes, mostly in the form of insecticidal carboxylic acid derivatives, in LA1777 (Coates et al., 1988, Frelichowski and Juvik, 2001; Li et al., 2004). Both species have greatly diverged in the types and amounts of terpenoids they accumulate in trichomes: S. lycopersicum mainly produces monoterpenes and traces of cI-Ss, whereas S. habrochaites var. LA1777 produces mainly cII-S carboxylic acids, small amounts of cI-Ss, and traces of monoterpenes.

Class I sesquiterpenes (cI-Ss) comprises germacrenes as well as alpha-humulene and beta-caryophyllene and class II sesquiterpenes (cII-Ss) comprises alpha-santalene, alpha-bergamotene, and beta-bergamotene.

Reference
1) Alvin F. Reeves II. (1977) Tomato trichomes and mutation affacting their development. Amer. J. Bot. 64(2): 186-189.
2) Gianfagna TJ, Carter CD, Sacalis JN (1992) Temperature and photoperiod influence trichome density and sesquiterpene content of Lycopersicon hirsutum f. hirsutum. Plant Physiol 100: 1403-1405
3) Katrin Besser, Andrea Harper, Nicholas Welsby, Ines Schauvinhold, Stephen Slocombe, Yi Li, Richard A. Dixon and Pierre Broun. (2009) Divergent Regulation of Terpenoid Metabolism in the Trichomes of Wild and Cultivated Tomato Species. Plant Physiology 149:499-514.
4) Li L, Zhao Y, McCaig BC, Wingerd BA, Wang J, Whalon ME, Pichersky E, Howe GA (2004) The tomato homolog of CORONATINE-INSENSITIVE1 is required for the maternal control of seed maturation, jasmonate-signaled defense responses, and glandular trichome development. Plant Cell 16: 126-143.
Publications: 18997116


Species: Solanum lycopersicum Common Name: tomato Taxonomy: Solaneae; Solanum; Lycopersicon Trichome Image
Description of Trichomes:
Glandular secreting trichomes (GST).

Five kinds of glandular trichomes have been found in tomato species, which are Type I, large with multicelluar base; Type III, intermediate in size with a single basal cell; Type V, short, slender, 1-4 celled; Type VI, short with a 2-4 celled glandular head and Type VII, 0.05-0.1 mm smaller glandular hairs with a 4-8 celled glandular head (Reeves 1977).

Type VI trichomes are particularly abundant on the leaves and stems of the cultivated species Solanum lycopersicum (formerly Lycopersicon esculentum) and its wild relative Solanum habrochaites (formerly Lycopersicon hirsutum) f. typicum LA1777 (Gianfagna et al., 1992). They have been shown to accumulate monoterpenes in S. lycopersicum and very high levels of sesquiterpenes, mostly in the form of insecticidal carboxylic acid derivatives, in LA1777 (Coates et al., 1988, Frelichowski and Juvik, 2001; Li et al., 2004). Both species have greatly diverged in the types and amounts of terpenoids they accumulate in trichomes: S. lycopersicum mainly produces monoterpenes and traces of cI-Ss, whereas S. habrochaites var. LA1777 produces mainly cII-S carboxylic acids, small amounts of cI-Ss, and traces of monoterpenes.

Class I sesquiterpenes (cI-Ss) comprises germacrenes as well as alpha-humulene and beta-caryophyllene and class II sesquiterpenes (cII-Ss) comprises alpha-santalene, alpha-bergamotene, and beta-bergamotene.

Reference
1) Alvin F. Reeves II. (1977) Tomato trichomes and mutation affacting their development. Amer. J. Bot. 64(2): 186-189.
2) Gianfagna TJ, Carter CD, Sacalis JN (1992) Temperature and photoperiod influence trichome density and sesquiterpene content of Lycopersicon hirsutum f. hirsutum. Plant Physiol 100: 1403-1405
3) Katrin Besser, Andrea Harper, Nicholas Welsby, Ines Schauvinhold, Stephen Slocombe, Yi Li, Richard A. Dixon and Pierre Broun. (2009) Divergent Regulation of Terpenoid Metabolism in the Trichomes of Wild and Cultivated Tomato Species. Plant Physiology 149:499-514.
4) Li L, Zhao Y, McCaig BC, Wingerd BA, Wang J, Whalon ME, Pichersky E, Howe GA (2004) The tomato homolog of CORONATINE-INSENSITIVE1 is required for the maternal control of seed maturation, jasmonate-signaled defense responses, and glandular trichome development. Plant Cell 16: 126-143.
Publications: 15094186 18997116 17440821 17235498 16628895 16334344 16132222 16047884 15772286 14974685 14688297 12677409 12466096 12223881 12194909 12164805 11757742 11681691 11027705 10948376 10737735 10517836 9605625 9204567 12223637 8980494 7840638 7972080 12244235 11607435 8329686


Species: Solanum pennellii Common Name: Taxonomy: Solaneae; Solanum; Lycopersicon
Description of Trichomes:
Glandular secreting trichomes (GST).

Of the tomato and its relatives, Solanum pennellii possesses high densities of type IV glandular trichomes on the leaf surfaces (Lemke and Mutschler, 1984). Type IV trichomes consist of a short, multicellular stalk and secrete droplets of sticky exudate at the tip.

The exudate of the type IV trichomes chiefly contains 2,3,4-triacylglucoses (Goffreda et al., 1989), which inhibit aphid settling and are correlated with field resistance to aphids (Goffreda et al., 1990).

Reference
1) Lemke CA and Mutschler MA (1984). lnheritance of glandular trichomes in crosses between Lycopersicon esculentum and L. pennellii. J. Am. SOC. Hort. Sci. 109, 592-596.
2) Goffreda JC, Ave DA, Mutschler MA, Steffens JC, and Tingey WM (1989). Aphid deterrence by glucose esters in glandular trichomes of the wild tomato, Lycopersicon pennellii. J. Chem. Ecol. 15,2135-2147.
3) Goffreda JC, Mutschler MA and Steffens JC (1990). Association of epicuticular sugars with aphid resistance in hybrids with wild tomato. J. Am. SOC. Hort. Sci. 115, 161-165.
4) Joseph C. Goffreda, Eugene J. Szymkowiak, lan M. Sussex, and Martha A. Mutschler. (1990) Chimeric Tomato Plants Show that Aphid Resistance and Triacylglucose Production Are Epidermal Autonomous Characters. The Plant Cell, 2:643-649
Publications: 18931142


Species: Solanum pimpinellifolium Common Name: currant tomato Taxonomy: Solaneae; Solanum; Lycopersicon
Description of Trichomes:
Publications: