Trichome

As is the case with many members of Lamiaceae, Satureja douglasii produces abundant essential oil from glandular trichomes on the leaves. Gas chromatographic analysis of the leaf oils from specimens collected throughout the species range revealed the presence of some dozen and a half well-known compounds. The major compounds identified were camphene [215], camphor [216], which, taken together, were considered to comprise the bicyclic type, carvone [217], pulegone [218], menthone [219], and isomenthone [220] (see Fig. 2.68 for structures 215-220). The predominance of each of these major components defined a terpene type. (All compounds were observed in each of the terpene types, most in comparatively small amounts, some only as traces.)... 

King, R. R., Calhoun, L. A., and Singh, L. A. 1988. 3,4-Di-O- and 2,3,4-tri-O-acylated gluco-side esters from the glandular trichomes of non-tuberous Solanum species. Phytochemistry 27 3765-3768. 

Kokkini, S., Karousou, R. and Vokou, D. 1994. Pattern of geographic variation of Origanum vulgare trichomes and essential oil content in Greece. Biochem. Syst. Ecol. 22 517-528. 

As depicted in Fig. 3, in glandular trichoma the cannabinoids are produced in the cells but accumirlate in the secretory sac of the glandular trichomes, dissolved in the essential oil [17-21]. Here, A9-THC was found to accumulate in the cell wall, the fibrillar matrix and the surface feature of vesicles in the secretory cavity, the subcutilar wall, and the cuticula of glandular trichomes [19]. 

Fig. 3 Representation of matiu-e secretory gland originated from C. sativa. The separate compartments of the glandular trichome are clearly shown, and the places where THC accumulates. Black areas nuclei, V vacuole, L vesicle, P plastid, ER endoplasmic reticulum. Picture obtained from http //www.hempreport.com/issues/17/malhodyl7.html...

In times of less accessibility of water, the plants seem to increase the cannabinoid content. It is suggested that the plant will cover itself with the oily cannabinoids to prevent water evaporation. For instance Sharma (1975) found increased glandular trichome densities in the leaves of Cannabis grown under dry circumstances [55]. 

Martell, E. A., Radioactivity of tobacco trichomes and insoluble cigarette smoke particles, Nature, 249 215-217 (1974). 

The action spectmm of positive and negative phototaxis of Anabaena variabilis was measured recently106). This species contains no C-phycoerythrin. Accordingly, maximum activity is found at around 615 nm (Fig. 7). In addition, in this form a second maximum occurs at around 675 nm, and a third small, but distinct, one at 440 nm, both indicating that chlorophyll a is also involved in the active light absorption (see above). The utilization via photosynthesis, however, could be excluded in this case, since the trichomes oriented themselves perfectly well to the light direction in the presence of photosynthetic inhibitors, such as DCMU and DBMIB, at concentrations in which the photosynthetic oxygen evolution was almost completely inhibited. 

When a trichome moves into a photosystem I light trap, electrons are drained out of the pool. In both cases a phobic response is caused, but different patterns result, one being an accumulation in, the other a dispersal from, the light trap l0]). 

A potential gradient between the two ends of a trichome, caused by light-induced potential changes, can be measured by two flat platinum electrodes mounted at a... 

Experiment 1. The secretory trichomes of allelopathically active species. 

Fig. 1 Leaf trichomes a - Calendula officinalis L., b - Nicotiana affinis L.

Fig. 2 OCM images of trichomes (shown by arrows) on the Urtica dioica L. leaf a - sting with silicon tip (edge) b - without tip (edge) c - ordinary trichome.

Fig. 1 The fluorescing images of secretory cells under luminescent microscope. A and B. Blue-fluorescing stinging and non-stinging secretory hairs of Urtica dioica, relatively on stem and leaf C and D - green-yellow-fluorescing leaf glandular trichomes of Lycopersicon esculentum and Solanum tuberosum, E. - Blue-fluorescing leaf cells of Achillea millefolium F - yellow fluoresced gland of leaf Calendula officinalis., G., H and I -secretory hairs, idioblasts and crystal on the surface on the root of Ruta graveolens, relatively.

WALKER, A.R., DAVISON, P.A., BOLOGNESI-WINFIELD, A.C., JAMES, C.M., SRINIVASAN, N., BLUNDELL, T.L., ESCH, J.J., MARKS, M.D., GRAY, J.C., The TRANSPARENT TESTA GLABRA1 locus, which regulates trichome differentiation and anthocyanin biosynthesis in Arabidopsis, encodes a WD40 repeat protein, Plant Cell,... 

JOHNSON, C.S., SMYTH, D.R., The TTG2 gene of Arabidopsis encodes a WRKY family transcription factor that regulates trichome development and the production of pigment and mucilage in seed coats, 9th International Conference on Arabidopsis Research. 1998, 186. 

Figure 9.1 Peppermint peltate glandular trichomes (A) scanning electron micrograph (courtesy of Dr. Glenn Turner) and (B) anatomical scheme of a cross-section.

McCASKILL, D., GERSHENZON, J., CROTEAU, R., Morphology and monoterpene biosynthetic capabilities of secretory cell clusters isolated from glandular trichomes of peppermint (Mentha x piperita L.), Planta, 1992,187, 445-454. 

GERSHENZON, J., McCASKILL, D., RAJAONARIVONY, J.I.M., MIHALIAK, C., KARP, F., CROTEAU, R., Isolation of secretory cells from plant glandular trichomes and their use in biosynthetic studies of monoterpenes and other gland products, Anal. Biochem., 1992, 200, 130-138. 

LANGE, B.M., WILDUNG, M.R., STAUBER, E.J., SANCHEZ, C., POUCHNIK, D., CROTEAU, R., Probing essential oil biosynthesis by functional evaluation of expressed sequence tags from mint glandular trichomes, Proc. Natl. Acad. Sci. USA, 2000, 97, 2934-2939. 

McCASKILL, D., CROTEAU, R., Monoterpene and sesquiterpene biosynthesis in glandular trichomes of peppermint Mentha x piperita) rely exclusively on plastid-derived isopentenyl diphosphate, Planta, 1995,197,49-56. 

Trichomes Single-celled or multicellular outgrowths of epidermal cells Produce volative oils for glandular trichomes reflect bright light in some desert plants increase boundary layer mechanically discourage predators salt secretion in some halophytes digestions in sundews... 

Lazzaro MD, Thomson WW. The vacuolar-tubular continuum in living trichomes of chickpea (Cicer arietinum) provides a rapid means of solute delivery from base to tip. Protoplasma 1996 193 181-190. 

Ryan ID, Gregory R, Tingey WH. Phenolic oxidase activities in glandular trichomes of Solarium berthauttii. Phytochemistry 1983 21 1885-1887. 

Kowalaksi SP. Bamberg J, Tringey WM, Steffens JC. Inheritance of polyphenol oxidase in type A glandular trichomes of Solanum berthaultii. JHered 1990 81 475-478. 

Sangster AG, Hodson MJ, Parry DW, Rees JA. A developmental study of silicifi-cation in the trichomes and associated epidermal structures of the grass Phalaris canariensis L. Ann Bot 1983 52 171-197. 

Teoh KH, Polichuk DR, Reed DW, Nowak G Covello PS. (2006) Artemisia annua L. (Asteraceae) trichome-specific cDNAs reveal CYP71AV1, a cytochrome P450 with a key role in the biosynthesis of the antimalarial sesquiterpene lactone artemisinin. FEBS Lett 580 1411-1416. 

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