The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
. Plasma-membrane-bound nitrate reductase (PM-NR) is located in roots and leaves of tobacco (Nicotiana tabacum L. cv. Samsun) and reduces nitrate with NADH as electron donor. When plasma membranes were prepared under specific protecting conditions, a PM-NR of roots was detected that accepts electrons from succinate to reduce nitrate. Comparison between the succinate dehydrogenase of mitochondria and...
Abstract. Brefeldin A, an inhibitor of protein secretion, caused typical alterations to the endomembrane system with limited effects on viability when given to unorganized carrot cells growing in suspension. When given to the same cells during particular stages of embryogenesis, it caused similar endomembrane lesions and an almost complete arrest of the embryogenic process. Addition of conditioned...
Abstract. Microsomal membrane preparations from the immature cotyledons of safflower (Carthamus tinctorius) catalysed the interconversion of the neutral lipids, mono-, di-, and triacylglycerol. Membranes were incubated with neutral lipid substrates, 14C-labelled either in the acyl or glycerol moiety, and the incorporation of radioactivity into other complex lipids determined. It was clear that diacylglycerol...
Abstract. During germination of Lupinus albus seeds, a 20-kDa polypeptide accumulates in the cotyledons of 4-d-old plants (Ferreira et al., 1995b, J Exp Bot 46: 211219). Immunological, polypeptide cleavage with cyanogen bromide and amino acid sequencing experiments indicate that the 20-kDa polypeptide and ubiquitin are structurally unrelated. However there is a strong sequence homology between the...
. The influence of the anti-fungal agent phosphonate (Phi) on the response of oilseed rape (Brassica napus L. cv. Jet Neuf ) cell suspensions to inorganic phosphate (Pi) starvation was examined. Subculture of the cells for 7 d in the absence of Pi increased acid phosphatase (APase; EC 3.1.3.2) and pyrophosphate (PPi)-dependent phosphofructokinase (PFP; EC 2.7.1.90) activities by 4.5- and 2.8-fold,...
. Attempts to devise models to account for the gravitropic behaviour of plant organs have been limited conceptually by the predominance of studies on the gravitropic behaviour of organs of young seedlings. The dramatic growth responses induced by gravitropic stimulation of young shoots or roots, which rapidly restore the elongating axes to vertical, are experimentally convenient but theoretically...
Abstract. Functional studies on molecular transport through plasmodesmata in leaf mesophyll and trichome cells revealed significant differences in their basal size-exclusion limits and their response to microinjected tobacco mosaic virus movement protein (E. Waigmann et al., 1994, Proc. Natl. Acad. Sci. USA 91: 14331437; E. Waigmann and P. Zambryski, 1995, Plant Cell 7: 20692079). To address the basis...
Abstract. In order to investigate the nature of genes expressed in leaf epidermal cells of higher plants, we have identified the nucleotide sequence of a cDNA designated ltp 7a2b encoding a novel nonspecific lipid transfer protein of barley (Hordeum vulgare L. cv. Gerbel). The cDNA of 755 basepairs contains an open reading frame of 366 nucleotides coding for a 12.3-kDa polypeptide. The first 29 amino...
. Tissue stresses, which occur in turgid herbaceous stems, both elongating and non-elongating, and tree growth stresses (TGSs) which occur in woody stems, are similar in that (i) they form self-equilibrating patterns of stresses (tensile and compressive) in stems, and (ii) the asymmetric, graviresponsive change in the pattern tends to bend the stem. The longitudinal tensile tissue stress (TS) which...
. Concerns regarding the reliability of slow- and fast-rotating uni-axial clinostats in simulating weightlessness have induced the construction of devices considered to simulate weightlessness more adequately. A new three-dimensional (3-D) clinostat equipped with two rotation axes placed at right angles has been constructed. In the clinostat, the rotation achieved with two motors is computer-controlled...
. Torenia fournieri Lind. has a naked embryo sac that protrudes from the micropyle. The precise time course of the entire process of double fertilization and the kinetics of fertilization events were determined in this species by the following methods: (i) without squashing, pollen tubes on the torn stylar canal were observed by fluorescence microscopy after staining with both 4′,6-diamidino-2-phenylindole...
. Microsomal membrane preparations from the immature cotyledons of safflower (Carthamus tinctorius) catalysed the interconversion of the neutral lipids, mono-, di-, and triacylglycerol. Membranes were incubated with neutral lipid substrates, 14C-labelled either in the acyl or glycerol moiety, and the incorporation of radioactivity into other complex lipids determined. It was clear that diacylglycerol...
Abstract. The role of gibberellin (GA) and ethylene in submergence-induced petiole elongation was studied in two species of the genus Rumex. Analysis of endogenous GAs in the flooding-tolerant Rumex palustris Sm. and the intolerant Rumex acetosa L. by gas chromatography-mass spectrometry showed for both species the presence of GA1, GA4, GA9, GA19, GA20 and GA53. Gas chromatography-mass spectrometry...
. Cell walls have been isolated from the mesocarp of mature grape (Vitis vinifera L.) berries. Tissue homogenates were suspended in 80% (v/v) ethanol to minimise the loss of water-soluble wall components and wet-sieved on nylon mesh to remove cytoplasmic material. The cell wall fragments retained on the sieve were subsequently treated with buffered phenol at pH 7.0, to inactivate any wall-bound enzymes...
Abstract. 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 1MNaCl or CaCl2. A number of different oxidase isoforms with isoelectric points in the range 85 were present in...
. Data and theories about the identity of the mass that acts in gravitropic sensing are reviewed. Gravity sensing may have evolved several times in plants and algae in processes such as gravitropism of organs and tip-growing cells, gravimorphism, gravitaxis, and the regulation of cytoplasmic streaming in internodal cells of Chara. In the latter and in gravitaxis, the mass of the entire cell may function...
. For more than a decade it has been assumed that there is a strong relationship between Ca2+ and gravitropism. There is evidence to suggest that the movement of Ca2+ in the wall might regulate extension growth and that free intracellular Ca2+ might mediate signalling in statocytes. However, it is unlikely that changes in either wall Ca2+ or the concentration of free intracellular calcium, [Ca2+]i...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.