Search

The present work aims to dissect the underlying signaling pathways associated with soybean [Glycine max (L.) Merrill] seed hormo-priming with ethephon (Eth). Our results demonstrated that soybean germination improved significantly upon Eth priming (Ethp). Phytohormone quantification shows relative enhanced endogenous gibberellin [A.sub.4] (G[A.sub.4]) levels concomitant with impaired biogenesis and signaling of auxin, viz., indole acetic acid (IAA) and abscisic acid (ABA). Phytochemical analysis revealed relative reduced levels of individual and total raffinose family oligosaccharide (RFO) components, starch, soluble sugars, and sucrose concomitant with enhanced levels of reducing sugars, glucose, cellular ATP, and acetyl-CoA pools. Secondary metabolite analysis revealed the activation of the mevalonate (MVA) pathway with a concomitant suppression of the plastidal 2-methyl-D-erythritol-4-phosphate/l-deoxy-D-xylulose-5-phosphate (MEP/DOX) and phenylpropanoid pathways, substantiated by relative reduced levels of total phenolics, tannins, and proanthocyanidin. Ethp also enhances the in vitro antioxidative activity (viz., 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging ability and ferric reducing antioxidant power (FRAP)) and endogenous antioxidants levels (viz., flavonoids, isoflavones, [beta]-carotene, vitamin C, and vitamin E). Further quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed transcriptional pattern of representative genes in agreement with these metabolic alterations. Keywords: soybean, germination, ethephon, raffinose family oligosaccharides, phytochemicals. Resume : Le present travail visait a dissequer les sentiers de signalisation associes a l'amorcage hormonal des graines chez le soya [Glycine max (L.) Merr.] a l'aide de l'ethephon (Eth). Les resultats montrent que la germination du soya est amelioree de maniere significative suite a l'amorcage a l'Eth. La quantification des regulateurs de croissance a monte un accroissement relatif des niveaux endogenes de la gibberelline [A.sub.4] (G[A.sub.4]), accompagne d'une production et d'une signalisation reduite de l'auxine (acide indole acetique, AIA) et de l'acide abscissique (ABA). Une analyse phytochimique a revele une reduction relative des niveaux d'oligosaccharides de la famille du raffinose (RFO), de l'amidon, des sucres solubles et du saccharose en meme temps qu'un accroissement des sucres reducteurs, du glucose, de l'ATP cellulaire et des puits d'acetyle-CoA. Une analyse des metabolites secondaires a revele que l'activation du sentier du mevalonate (MVA) en meme temps qu'une suppression des sentiers des phenylpropano'ides et de la 2-methyle-D-erythritol-4-phosphate/l-desoxy-D-xylulose-5-phosphate (MEP/DOX) plastidiques. Ces changements ont ete confirmes par une reduction des composes phenoliques, des tannins et des proanthocyanidines. L'amorcage a egalement augmente l'activite antioxydante in vitro (le balayage des radicaux 2,2-diphenyle-l-picryl hydrazyle (DPPH) et le pouvoir reducteur du fer (FRAP)) ainsi que les niveaux endogenes d'antioxydants (flavono'ides, isoflavones, [beta]-carotene, vitamines C et E). Des analyses qRT-PCR ont montre que l'activite transcriptionnelle de genes representatifs de ces changements etaient en accord avec ces alterations metaboliques. [Traduit par la Redaction] Mots-cles : soya, germination, ethephon, d'oligosaccharides de la famille du raffinose, produits phytochimiques., Introduction Soybean [Glycine max (L.) Merrill] an annual, dicot, diploid (2n = 40), oilseed crop, and being the 'functional food of the century', is one of the most important contributors [...]

Seed germination requirements for S. alata were investigated using cold stratification and phytohormones. Treatments included no stratification (control), two week, three week, four week, five week, and six week cold stratification. Hormone treatments included no stratification with cytokinin, no stratification with gibberellins, no stratification with cytokinin and gibberellins, no stratification with auxin, and one with six week stratification with abscisic acid. Three weeks cold stratification was required to yield a significant increase in percent germination. Gibberellin was the only hormone which caused a significant increase in germination in S. alata seeds. Keywords: abscisic acid, auxin, cytokinin, gibberellin, pitcher plant, Carnivorous plants have specialized traps to capture and digest animal prey for nutrient assimilation. Sarracenia alata, a pitcher plant native to regions in south eastern North America, including parts of [...]

The seed coat of fir (Abies), hemlock (Tsuga), and cedar (Thuja) species contain terpenoid resin vesicles. Although information is limited about the morphology and allelopathy of these vesicles, their damage during seed processing can negatively impact germination success. We examined resin vesicle morphology of western redcedar (Thuja plicata Donn ex D. Don), eastern white cedar (Thuja occidentalis L.), amabilis fir (Abies amabilis Douglas ex J. Forbes), balsam fir (Abies balsamea (L.) Mill.), grand fir (Abies grandis (Douglas exD. Don) Lindl), and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) seeds by [sup.1]H magnetic resonance imaging to characterize resin vesicle volume, shape, and number. Western redcedar genotypes with known differences in the quantity of foliar monoterpenes also had parallel differences in the resin vesicle volume of corresponding seeds. Germination assays with the cedar and fir species, eastern hemlock (Tsuga canadensis (L.) Carriere), mountain hemlock (Tsuga mertensiana (Bong.) Carriere), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) confirmed that resin vesicle damage prior to stratification (moist chilling) significantly reduced germination success for most species. Extracts of these resin vesicles from the Abies and Thuja species strongly inhibited the germination of Arabidopsis Col-0 seeds but inhibited the germination of only a small percentage of Arabidopsis abscisic acid insensitive mutant abi3-6 seeds. Resin extracts from Thuja species were 10 times more effective than those from Abies species in inhibiting Arabidopsis Col-0 germination.Key words: magnetic resonance imaging (MRI), germination, conifer, seeds, terpenoids, allelopathy.L'enveloppe des graines du sapin (Abies), de la pruche (Tsuga) et du thuya (Thuja) contient des vesicules resiniferes remplies de terpenoides. Bien que l'information concernant la morphologie et l'allelopathie de ces vesicules soit limitee, les dommages qu'ils causent durant le conditionnement des graines peuvent avoir un impact negatif sur le succes de germination. Nous avons etudie la morphologie des vesicules resiniferes des graines du thuya geant (Thuja plicata Donn ex D. Don), du thuya occidental (Thuja occidentalis L.), du sapin gracieux (Abies amabilis Douglas ex J. Forbes), du sapin baumier (Abies balsamea (L.) Mill.), du sapin grandissime (Abies grandis (Douglas ex D. Don) Lindl) et du sapin subalpin (Abies lasiocarpa (Hook.) Nutt.) a l'aide de l'imagerie par resonnance magnetique H-1 pour caracteriser le volume, la forme et le nombre de vesicules resiniferes. Des genotypes de thuya geant connus pour avoir differentes quantites de monoterpenes foliaires avaient aussi des differences correspondantes dans le volume de vesicules resiniferes de leurs graines. Des tests de germination avec les especes de pruche et de sapin, la pruche du Canada (Tsuga canadensis (L.) Carriere), la pruche subalpine (Tsuga mertensiana (Bong.) Carriere) et la pruche de l'Ouest (Tsuga heterophylla (Raf.) Sarg.) ont confirme que les dommages causes par les vesicules resiniferes avant la stratification (refroidissement humide) ont significativement reduit le taux de germination de la plupart des especes. Des extraits de ces vesicules resiniferes provenant d'especes d'Abies et de Thuja ont fortement inhibe la germination des graines d'Arabidopsis Col-0 mais ont inhibe la germination de seulement un faible pourcentage des graines du mutant abi3-6 d 'Arabidopsis insensible a l'acide abscisique. Les extraits de la resine provenant des especes de Thuja etaient 10 fois plus efficaces que ceux des especes d'Abies pour inhiber la germination d'Arabidopsis Col-0. [Traduit par la Redaction]Mots-cles: imagerie par resonnance magnetique (IRM), germination, conifere, graines, terpenoides, allelopathie., IntroductionMost species of conifers have cones that contain, and sometimes ooze, oleoresin (Farjon 2008). These are thought to have important roles in the defense against cone and seed pests and [...]