Idioblasts

Experiment 1. Visual observation of secretory cells in luminescence microscope Various types of secretory cells in allelopathically active plants contain fluorescing secondary products (Fig. 1). Secretions from the above ground parts of plant (in leaves, flowers, stems) were concentrated in secretory hairs and glands. Whereas secretions of roots are in secretory reservoirs and idioblasts (ordinary cells which accumulate secretory products) or may be released by the secretory surface of the root tip (Fig. 1.). The fluorescence appears to change, when allelopathically active cell of other plant species (cell-donor) interacts with acceptor cell (Roshchina and Melnikova, 1999). 

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.

Fig. 3 The fluorescence spectra of secretory cells seen on flower, leaf and root of Achilea millefolium (left) and of Gaillardia pulchella (right). Unbroken fatty line - secretory hair unbroken thick line - idioblast broken line - non-secretory cell dotted line - crystal on the surface (secretion).

Sugimura Y, Mori T, Nitta I, Kotani E, Furusawa T, Tatsumi M, Kusakari S-I, Wada M, Morita Y. Calcium deposition in idioblasts of mulberry leaves. Ann Bot 1999 ... 

Rodriguez-Saona C, Millar JG, Maynard DF,Trumble JT, Novel anttfeedant and insecticidal compounds from avocado idioblast cell oil,/ Chem Ecol24 867—889,... 

We use the term myrosin cell structurally (see above), and not functionally (i.e., if a cell contains myrosinase it should be called a myrosin cell). This structural definition should be used because myrosin cell is a well-established anatomical term for this special idioblast. We do not find it useful to coin a specific term for a cell just because a certain protein is expressed in it, especially now in the post-genomic era, where possibly thousands of different proteins can be found in every cell. Husebye et al. named guard cells in Arabidopsis myrosin guard cells because myrosinase was found in these cells.47 This is problematic since these cells do not... 

BORGEN, B.H., Functional Analysis of Plant Idioblasts (Myrosin Cells) and their Role in Defence, Development and Growth., PhD thesis, Norwegian University of Science and Technology, Trondheim, Norway, 2002. 

ANDREASSON, E., JORGENSEN, L.B., HOGLUND, A.-S., RASK, L., MEIJER, J., Different myrosinase and idioblast distribution in Arabidopsis and Brassica napus., Plant Physiol., 2001,127,1750-1763. 

HUSEBYE, H., CHADCHAWAN, S., WINGE, P., THANGSTAD, O.P., BONES, A.M., Guard cell- and phloem idioblast-specific expression of thioglucoside glucohydrolase 1 (myrosinase) in Arabidopsis., Plant Physiol., 2002,128,1180-1188. 

The translocation of pathway intermediates is also suggested by differential localization of TLA biosynthetic enzymes. In situ hybridization and immunolocalization studies have shown that CYP72A1, TDC, and STR are localized to the epidermis of immature leaves, stems, and flower buds.52,147 In contrast, D4H and DAT are associated with laticifers and idioblasts of shoot organs. Laticifers and idioblasts are distributed throughout the mesophyll in C. roseus leaves, and are often several cell layers away from the epidermis. Vindoline biosynthesis involves at least two distinct cell types and requires the intercellular translocation of a pathway intermediate (Fig.7.9B). The differential localization of the early and late steps of vindoline biosynthesis might partially explain why this alkaloid is not produced in dedifferentiated C. roseus cell cultures. 

Several different tissue types - epidermis, endodermis, laticifers, idioblasts, pericycle, and cortex — have now been implicated in the biosynthesis and/or accumulation of various alkaloids in plants. Recently, we have localized berberine in the endodermis of Thalictrum flavum roots at the onset of secondary growth.150 Rather than being sloughed off, the endodermis was found to undergo extensive anticlinal division leading to an expanding cellular cylinder that ultimately displaced all external tissues. Endodermal-specific berberine accumulation continued throughout root development, but was extended to include 3 to 4 layers of smaller pericycle cells in the oldest roots near the base of the stem. The cell type-specific accumulation of an antimicrobial alkaloid and the unusual development of the endodermis and pericycle in T. flavum roots are consistent with the putative role of berberine in plant defense. 

Extensive studies to quantitate the production of indole alkaloids in Catharanthus roseus hairy root cultures have revealed that they accumulate several compounds including ajmalicine, serpentine, catharanthine, tabersonine, horhammericine, and lochnericine.27, 28 The presence of tabersonine in hairy roots has raised speculations that this intermediate in vindoline biosynthesis, together with catharanthine, is transported from this potential site of biosynthesis through the vasculature to the stem and to the leaves where tabersonine is further elaborated into vindoline within laticifers and/or idioblasts.26 However, oxidized derivatives of tabersonine, such as horhammericine and lochnericine, are present at 5 to 15 times the levels of tabersonine in hairy roots,27 and presumably this prevents their transport and/or use for vindoline biosynthesis. In this context, it would be interesting to... 

The Ruta alkaloids are usually found in idioblasts and early experiments using fluorescent microscopy, and Ruta graveolens showed heavy deposits of acridone alkaloids in the xylem (Wink and Roberts, 1998). 

In Brassica, the myrosin cells are scattered throughout most tissues of glucosinolafe-confaining plants (Andreasson et al, 2001 Thangstad et al, 2004). In contrast, in Arabidopsis, these myrosinase -containing idioblasts were found in fhe phloem parenchyma additionally, myrosinase is located in the guard cells (Andreasson et al, 2001 Husebye et al, 2002 Thangstad et al, 2004). 

Horner H. T., Kausch A. P., and Wagner B. L. (2000) Ascorbic acid a precursor of oxalate in crystal idioblasts of Yucca torreyi in liquid root culture. Int J. Plant Sci. 161(6), 861-868. 

FumariacecR or Fumitory Family.— Delicate herbs rarely shrubs containing milky watery to watery latex. Leaves more or less compound. Inflorescence a raceme or spike. Flowers irregular, zygomorphic, one or both of the petals of which having a spur. Fruit a one-chambered capsule. Seeds albuminous. Idioblasts common. 

Buchan terrane, and a Barrovian terrane, which is replaced by allanite with increasing grade before an idioblastic variety appears at the Al2Si05 isograd. 

Alkaloids generally aeeumulate in speeifie eell types due to their eytotoxicity and probable role in plant defense responses. For example, alkaloids are sequestered to isolated idioblasts and latieifers in C. roseus (234,235), root endodermis and stem eortex or pith in T flaman (236), and latieifers in opium poppy (237). Within eells, alkaloids are often stored in diserete vesieles or the eentral vaeuole (238). The eell type- and organelle-speeifie aeeumulation of alkaloids has prompted studies on the cellular and subeellular loeahzation of the relevant biosynthetie pathways. The eell biology of alkaloid biosynthesis is remarkably diverse and eomplex (Fig. 2). 

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