Planta
Abstract. Immunogold labeling was used to study the distribution of (13)--glucans and (13, 14)--glucans in the rice grain during cellularization of the endosperm. At approximately 35d after pollination the syncytial endosperm is converted into a cellular tissue by three developmentally distinct types of wall. The initial free-growing anticlinal walls, which compartmentalize the syncytium into open-ended...
Abstract. A novel cDNA clone osr40c1, encoding a abscisic acid (ABA)-responsive 40-kDa protein previously associated with salt tolerance (Moons et al. `1995 Plant Physiol 107: 177186), was isolated from roots of rice seedlings (Oryza sativa L.). Exogenously applied ABA and salt shock induced a marked increase of the osr40c1 transcript level in roots of seedlings whereas constant osr40c1 mRNA levels...
Abstract. Two ferredoxin-dependent proteins, nitrite reductase and glutamate synthase, play a role in nitrate assimilation during the anaerobic germination of rice (Oryza sativa L.). This paper reports the expression of the root form of ferredoxin-NADP+ oxidoreductase (FNR), the protein responsible for providing reduced ferredoxin in rice coleoptiles. Using an antibody against FNR, a protein with...
Abstract. Tomato (Lycopersicon esculentum L.) plants accumulate proteinase inhibitor (pin) mRNA in response to various stimuli in leaves distant from those treated. Most earlier work suggests that the intercellular wound signals are chemical; we have tried to determine whether electrical or hydraulic signals can also evoke systemic pin expression. We used a mild flame to evoke a hydraulic signal and...
Abstract. Phase responses to red and blue light pulses were measured at different times during the circadian cycle (phase response curves, PRC) in the marine unicellular dinoflagellate Gonyaulaxpolyedra Stein. Pulses were given during a 24-h period of darkness; thereafter, cultures were released into constant dim red light for the assessment of phase and period. The results confirmed earlier findings...
Abstract.Galdieria sulphuraria (Galdieri) Merola can grow heterotrophically on at least ten different polyols. We investigated their metabolic path to glycolysis/gluconeogenesis and identified two NAD-dependent polyol dehydrogenases. Activity of other enzymes metabolizing mannitol or sorbitol could not be detected. The two dehydrogenases had a broad substrate specificity and were termed xylitol dehydrogenase...
Abstract. Parasitic plants use host molecules to trigger developmental programs essential for parasitism. One such program governs the initiation, development, and function of haustoria, parasite-specific organs responsible for attachment and invasion of host tissues. Haustoria development can be initiated by several different molecules produced by appropriate host species. We are interested in understanding...
Abstract. The NADH-dependent Fe3+-chelate reductase (NFCHR) of tomato (Lycopersicon esculentum L.) roots, a strategy I species, was investigated. The Fe3+-citrate reductase (FeCitR) assay was strongly inhibited by p-hydroxymercuribenzoic acid (PHMB); moreover, the inhibitor was found to be more specific to the FeCitR assay than to the Fe3+-EDTA reductase assay, which was catalyzed by at least another...
Abstract. Light is the main environmental signal (zeitgeber) for practically all circadian systems, but little is known about the transduction mechanisms by which light signals reach the circadian oscillator. To identify components involved in the circadian light transduction pathway in the unicellular alga Gonyaulax polyedra Stein, we assayed inhibitors of pigment synthesis and of flavo-enzymes for...
Abstract. The objective of the present study was to assess whether, in barley, nitrogen supply limits the rate of leaf elongation through a reduction in (relative) cell elongation rate and whether this is attributable to a reduced turgor, a reduced availability of osmolytes or, by implication, changed wall properties. Plants were grown on full-strength Hoagland solution (Hoagland-plants), or on N-deficient...
Abstract. Cotton (Gossypium hirsutum cv. MD51) fiber cell walls were analyzed with an atomic force microscope to determine the effect of chemical treatments on cell wall organization and topography. Analysis of fibers in either air or water and without any staining or coating produced high-resolution images of cell wall microstructure which could be used for detailed quantitative analysis. Treatment...
Abstract. In this paper we report the in-planta activity of the ribosome-inactivating protein JIP60, a 60-kDa jasmonate-induced protein from barley (Hordeum vulgare L.), in transgenic tobacco (Nicotiana tabacum L.) plants. All plants expressing the complete JIP60 cDNA under the control of the cauliflower mosaic virus (CaMV) 35S promoter exhibited conspicuous and similar phenotypic alterations, such...
Abstract. Auxin and elicitors reportedly activate phospolipase A. A number of inhibitors known to inhibit animal phospholipase A2 were tested for their ability to inhibit hormone and fusicoccin-induced growth. To this end, growth induced by indolyl-3-acetic acid and 2,4-dichlorophenoxyacetic acid in hypocotyl segments of etiolated zucchini (Cucurbita pepo L.) seedlings was determined in the presence...
. Microsomal preparations from developing castor bean (Ricinus communis L.) endosperm catalyzed remodelling of in-situ-formed triacylglycerol (TAG) species. Castor bean microsomal membranes synthesized [14C]TAGs from either glycerol 3-phosphate and [14C]ricinoleoyl-CoA or [14C]glycerol 3-phosphate and ricinoleoyl-CoA. Upon repelleting and subsequent incubation of the microsomes a redistribution occurred...
. Unicellular tip-growing cells are excellent experimental systems in which to study gravitropism because cell extension, gravity sensing and the gravity response are all confined to the apical dome. Thus various approaches can be used to determine the distinct steps of the short gravitropic signal-transduction chain, which lacks a signal-transmission phase between the gravity-sensing cells and the...
. Roots of many species grow downward (orthogravitropism) only when illuminated. Previous work suggests that this is a calcium-regulated response and that both calmodulin and calcium/calmodulin-dependent kinases participate in transducing gravity and light stimuli. A genomic sequence has been obtained for a calcium/calmodulin-dependent kinase homolog (MCK1) expressed in root caps, the site of perception...
. Expression of the ArabidopsisTCH genes is markedly upregulated in response to a variety of environmental stimuli including the seemingly innocuous stimulus of touch. Understanding the mechanism(s) and factors that control TCH gene regulation will shed light on the signaling pathways that enable plants to respond to environmental conditions. The TCH proteins include calmodulin, calmodulin-related...
. Oxidase activity in the developing xylem of branches of Sitka spruce [Picea sitchensis] (Bong) Carr. was expressed in synchrony with the deposition of lignin. The activity was closely associated with the cell wall but it could be extracted by elution with salt solutions such as 1 M NaCl or CaCl2. A number of different oxidase isoforms with isoelectric points in the range 8–5 were present in these...
Abstract. The determinate growth of the primary root, its organization and relationship with lateral-root development, and the possible ecological significance of this growth pattern were analyzed in three sympatric species of Cactaceae from the Sonoran Desert, Stenocereus gummosus (Engelm.) Gibson Horak, S. thurberi (Engelm.) Buxbaum and Ferocactus peninsulae (F.A.C. Weber) Britton Rose, var. townsendianus...
. Formation and/or positioning of a protuberance, or peg, in cucumber (Cucumis sativus L.) seedlings is controlled by gravity. The gravisensing apparatus for this gravimorphogenesis is possibly shared with that of gravitropism. Sheath cells in the transition zone between stem and root contain sedimentable amyloplasts, but amyloplasts in cortical cells (peg cells) do not sediment uniformly. These putative...