RAZINE LIPIDNE PEROKSIDACIJE U DIJELOVIMA SJEMENA SOJE (Glycine max (L.) Merr.) KAO POSLJEDICA STRESA PRI USVAJANJU VODE

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age.Intenzivne oborine i intenzivno usvajanje vode suhoga sjemena nakon sjetve u polju mogu rezultirati takozvanim imbibicijskim oštećenjem sjemena. U ovom istraživanju analiziran je intenzitet lipidne peroksidacije u sjemenjači, klici i kotiledonima sjemena tri sorte soje (Podravka 95, Tisa i Vita), nakon 3, 6, 12 i 24 imbibicije u vodi pri 20oC. U cjelini, lipidna peroksidacija bila je povećana u klici soje, a najslabije izražena u sjemenjači. S obzirom na dužinu imbibicije, najveći intenzitet lipidne peroksidacije utvrđen je nakon 3 h imbibicije, nakon čega se smanjivao kod sorata Podravka 95 i Vita, uz sličan trend, s obzirom na sjeme iste starosti

Agronomic processes to optimise galanthamine content of daffodil biomass (AGROGAL)

The objective of the research is to identify individual agronomically-relevant processes and treatments that would increase the production of the anti-Alzheimer drug, Galanthamine, in daffodils (to identify the basis of the so called Black Mountain Effect observed in the field). The data was generated by extensive and reproducible analysis of 18 different treatments applied individually under laboratory and greenhouse conditions

Fluctuations and Intrinsic Pinning in Layered Superconductors

A flux liquid can condense into a smectic crystal in a pure layered superconductors with the magnetic field oriented nearly parallel to the layers. If the smectic order is commensurate with the layering, this crystal is {\sl stable} to point disorder. By tilting and adjusting the magnitude of the applied field, both incommensurate and tilted smectic and crystalline phases are found. We discuss transport near the second order smectic freezing transition, and show that permeation modes lead to a small non--zero resistivity and large but finite tilt modulus in the smectic crystal.Comment: 4 pages + 1 style file + 1 figure (as uufile) appended, REVTEX 3.

Problems With the Vortex-Boson Mapping in 1+1 Dimensions

Using the well known boson mapping, we relate the transverse magnetic susceptibility of a system of flux vortices in 1+1 dimensions to an appropriately defined conductivity of a one-dimensional boson system. The tilt response for a system free of disorder is calculated directly, and it is found that a subtle order of limits is required to avoid deceptive results.Comment: 4 Pages (REVTeX 3.0). Postscript file for this paper is available on the World Wide Web at http://cmtw.harvard.edu/~simon/

Hypoxia and nitrate reductase signalling in Arabidopsis thaliana

Nitric oxide (NO) is emerging as an important signalling molecule in plants. A major source of NO in planta is through the activity of nitrate reductase (NR),an enzyme required for nitrate reduction that can also reduce nitrite to NO. The model plant Arabidopsis thalianahas been extensively used to study mechanisms of NO production and signalling. Arabidopsis contains two isoforms of NR, NITRATE REDUCTASE 1 (NIAl) and NITRATE REDUCTASE 2 (NIA2). Increasing evidence suggests diverse roles for these proteins in NO production modulating plant development, biotic and abiotic stress tolerance. Low-oxygen or hypoxic stress, induced by periods of waterlogging or 'submergence, is a significant factor impacting plant and crop growth and survival globally. Terrestrial plants have evolved diverse mechanisms to cope with these stresses including alterations in gene expression, metabolism, morphology and physiology. In this thesis, Arabidopsis was used to as a model plant to investigate the putative regulation of these processes via NR and NO signalling. This investigation has focused primarily on analysing the initiation of stomatal closure, the formation of aerenchyma, and the induction of hypoxic gene expression in wild- type Arabidopsis plants and NIA gene knockout mutants. Waterlogging stress induced hypoxia in the root environment within 4 days, at which time stomatal aperture was significantly reduced in wild-type plants. In NIAI gene mutants, stomatal closure was completely abolished whilst closure occurred normally in the NIA2 mutant. Ethylene signal transduction and reactive oxygen species (ROS) production, mediated by ERECTA, ETRl, RBOHF, EIN2 and EIN3 were also shown to be critical for this response. The data suggest a role for NIAl in waterlogging stress induced guard cell NO generation. Under waterlogging stress conditions, stomata of wild-type plants were insensitive to exogenous NO, which functionally restored stomatal closure in NIAI and other mutants compromised in the stomatal response. A model is proposed whereby waterlogging stress induces ethylene and ROS signalling which acts upstream of NO production to regulate stomatal aperture during rhizospheric hypoxia. Aerenchyma is made up of gas spaces (lacunae) formed by apoptotic cell death of localised cells and is proposed to facilitate gas-exchange in submerged plant tissues. In Arabidopsis hypocotyls, prolonged waterlogging induced cell death leading to aerenchymous lacunae, as measured by anatomical analyses of hypocotyl sections. NR was not suggested to be required for cell death leading to aerenchyma, since NIA gene mutants exhibited equivalent lacunae formation to wild-type plants. A hydroponic cultivation system was employed to study hypoxic root gene expression. The upregulation of hypoxic tolerance genes, ALCOHOL DEHYDROGENASE 1 (ADHI) and HAEMOGLOBIN I(AHBI) was attenuated in a NIAI mutant and to a lesser extent in a NIA2 mutant over a 24 hour period of hypoxic stress, although whether this was attributed to NO production could not be confirmed. AffymetrixGeneChiptranscriptome profiling identified hypoxia-induced alterations in gene expression at 24 hours hypoxia in wild-type and NIA 1 mutant roots. Functional analysis of differentially expressed transcripts was performed utilising gene ontology annotations for the Arabidopsis genome. The analysis identified known hypoxia-associated processes significantly enriched amongst up or downregulated genes, and identified novel pathways directly or indirectly regulated by NIAl function. These cumulative data support an important role of NR and specifically NIAl in the regulation of hypoxic stress tolerance mechanisms at the physiological and molecular level.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Lipid peroxidation levels in soybean (Glycine max (L.) Merr.) seed parts as a consequence on imbibition stress

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age

LIPID PEROXIDATION LEVELS IN SOYBEAN (Glycine max (L.) Merr.) SEED PARTS AS A CONSEQUENCE OF IMBIBITION STRESS

High rainfall and rapid water uptake by dry seed after sowing in the field can result in so-called seed imbibitional damage. Here, lipid peroxidation levels were evaluated in seed testa, embryos and cotyledons of three soybean cultivars (Podravka 95, Tisa and Vita), after 3, 6, 12 and 24 h of seed imbibition in water at 20oC. In general, lipid peroxidation was enhanced in soybean embryos and the lowest vales were observed in seed testa. With respect to imbibition duration, the highest lipid peroxidation was observed after 3 h of imbibition and decreased thereafter in seed of Podravka 95 and Vita, with similar trend regarding seed of the same age

A novel hydrogen sulfide donor causes stomatal opening and reduces nitric oxide accumulation

Effects of hydrogen sulfide (H2S) on plant physiology have been previously studied, but such studies have relied on the use of NaSH as a method for supplying H2S to tissues. Now new compounds which give a less severe H2S shock and a more prolonged exposure to H2S have been developed. Here the effects of one such compound, GYY4137, has been investigated to determine its effects on stomatal closure in Arabidopsis thaliana. It was found that both NaSH and GYY4137 caused stomatal opening in the light and prevented stomatal closure in the dark. Nitric oxide (NO) has been well established as a mediator of stomatal movements and here it was found that both NaSH and GYY4137 reduced the accumulation of NO in guard cells, perhaps suggesting a mode of action for H2S in this system. GYY4137, and future related compounds, will be important tools to unravel the effects of plant exposure to H2S and to determine how H2S may fit into plant cell signalling pathways. © 2010 Elsevier Masson SAS