In situ RNA hybridization and immunocytochemistry were used to establish the cellular distribution of monoterpenoid indole alkaloid biosynthesis in Madagascar periwinkle (Catharanthus roseus). Tryptophan decarboxylase (TDC) and strictosidine synthase (STR1), which are involved in the biosynthesis of the central intermediate strictosidine, and desacetoxyvindoline 4-hydroxylase (D4H) and deacetylvindoline 4-O-acetyltransferase (DAT), which are involved in the terminal steps of vindoline biosynthesis, were localized. tdc and str1 mRNAs were present in the epidermis of stems, leaves, and flower buds, whereas they appeared in most protoderm and cortical cells around the apical meristem of root tips. In marked contrast, d4h and dat mRNAs were associated with the laticifer and idioblast cells of leaves, stems, and flower buds. Immunocytochemical localization for TDC, D4H, and DAT proteins confirmed the differential localiza-tion of early and late stages of vindoline biosynthesis. Therefore, we concluded that the elaboration of the major leaf al-kaloids involves the participation of at least two cell types and requires the intercellular translocation of a pathway intermediate. A basipetal gradient of expression in maturing leaves also was shown for all four genes by in situ RNA hy-bridization studies and by complementary studies with dissected leaves, suggesting that expression of the vindoline pathway occurs transiently during early leaf development. These results partially explain why attempts to produce vin-doline by cell culture technology have failed. INTRODUCTION The organs forming the plant body consist of several different cell types that are organized in relation to each other and that confer specific functions to the resulting organ. Each cell type emerges from an undifferentiated meristem according to a sophisticated and partially understood developmental program (Sylvester et al., 1996; von Arnim and Deng, 1996). The commitment to differentiate into specialized structures involves the perception by cells in the meristem of a complex array of signals, which communicate cellular age, position in relation to other cells, and hormonal balance. Environmental factors, such as light and temperature, also play a critical role in modulating these signals throughout the process of organogenesis (Bernier, 1988; Dale, 1988; Sylvester et al., 1996). In addition to morphogenesis, developmental processes result in biochemical specialization of cells for the biosyn-thesis and/or accumulation of secondary metabolites, such as phenylpropanoids (Ibrahim et al.
Abstract-Frequency selective surfaces (FSS) filter specific electromagnetic (EM) frequencies defined by the geometry and often fixed periodic spacing of a conductive element array. By embedding the FSS pattern into an origami structure, we expand the number of physical configurations and periodicities of the FSS, allowing for fold-driven frequency tuning. The goal of this work is to examine the folddependent polarization and frequency behavior of an origami-inspired FSS under normal incidence and provide physical insight into its performance. The FSS is tessellated with the Miura-ori pattern and uses resonant length metallic dipoles with orthogonal orientations for two primary modes of polarization. A driven dipole model with geometric morphologies, representative of the folding operations, provides physical insight into the observed behavior of the FSS. Full-wave simulations and experimental results demonstrate a shift in resonant frequency and transmissivity with folding, highlighting the potential of origami structures as an underlying mechanism to achieve fold-driven EM agility in FSSs.
Species Principal constituents ReferenceAbies balsamea Mill -and -pinene, -phellandrene, limonene Achillea biebersteinii Afan piperitone, or cineol and camphor Aloysia triphylla (L'Herit.) Britton citral, limonene Alpinia conchigera Griff. cineol Alseuosmia macrophylla A. Cunn. flowers: linalool Ambrosia microcephala DC. camphor, bornyl acetate Amomum subulatum Roxb. cineol, -terpineol, -and -pinene Artemisia afra yomogi alcohol, artemisyl acetate Artemisia afra Willd. cineol, terpinen-4-ol, borneol Artemisia ordosica -and -pinene, sabinene Austromyrtus dulcis (C. T. White) L. S. Smith (chemotype) -pinene, cineol Boronia megastigma Nees. -ionone, 8-hydroxylinalyl esters, geranyloxy cinnamate Bouea macrophylla Griff. ( E)--ocimene, -pinene Calamintha cretica piperitenone, piperitenone oxide Calamintha incana (Sm.) Boiss. piperitenone oxide Callistemon speciosus Anthor. cineol, -pinene, -terpineol Canella winteriana Gaertn. stem and bark: cineol, terpinen-4-ol, -terpinyl acetate, -terpineol; leaves: myrcene Cedronella canariensis Webb et Berth. ssp. canariensis pinocarvone Chamelaucium uncinatum genotypes -pinene, citronellal, limonene, linalool, -terpinyl acetate Chenopodium ambrosioides limonene, trans-pinocarveol Chenopodium botrys -8 Chrysanthemum balsamata carvone, camphor Chrysanthemum lavandulaefolium menthol Cinnamomum camphora Nees et Ebermaier camphor, cineol, terpinen-4-ol, limonene Cinnamomum puciflorum -2 Citrus grandis limonene Clausena anisata (Willd.) J. D. Hook limonene, myrcene Coleus aromaticus carvacrol, camphor Coreopsis barteri Oliv. & Hiern limonene, -phellandrene Coreopsis grandis Hogg ex Sweet myrcene Coriandrum sativum seeds: linalool Coridothymus capitatus Reich. f. carvacrol 98, 99 Cunila fasiculata menthofuran Cunila microcephala menthofuran, limonene Curcuma aeruginosa Roxb. cineol, camphor Curcuma amada Roxb. myrcene Curcuma aromatica Salisb. cineol, camphor, isoborneol, camphene Curcuma cochinchinensis Gagnep. cineol Curcuma domestica -phellandrene, cineol, p-cymene, -pinene Curcuma pierreana Gagnep. Rhizome, stem: isoborneol, isobornyl acetate leaf: isoborneol, camphor Croton aubrevillei J. Leonard linalool Croton zambesicus Muell. Arg. linalool Cyclotrichum origanifolium (Labill.) Manden. et Scheng. cis-isopulegone, pulegone, isomenthone, menthol Cymbopogon caesius (Nees et Hook. et Arn.) Stapf. perillyl alcohol, geraniol, limonene Cymbopogon citratus (DC.) Stapf. citral, geraniol, myrcene, -and -pinene Cymbopogon khasianus (Munro ex Hack.) Bor. geraniol, geranyl acetate, linalool Cymbopogon schoenanthus piperitone, limonene Daphne mezereum flowers: linalool, linalyl oxides Echinophora chryantha Freyn et Sint. -phellandrene Egletes viscosa various terpenol acetates Elsholtzia ciliata (Thunb.) Hyland chemotype (a): elsholtzia ketone, -thujone chemotype (b): neral, geranial, limonene
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