Planta
Abstract. Wild-type Ceratodon purpureus (Hedw.) Brid. protonemata grow up in the dark by negative gravitropism. When upright wild-type protonemata are reoriented 90, they temporarily grow down soon after reorientation (initial reversal) and also prior to cytokinesis (mitotic reversal). A positively gravitropic mutant designated wrong-way response (wwr-1) has been isolated by screening ultraviolet...
Abstract. A mutant (LaPr 87/30) of barley (Hordeum vulgare L.) deficient in glycine decarboxylase (GDC; EC 2.1.2.10) was crossed with wild-type plants to generate heterozygous plants with reduced GDC activities. Plants of the F2 generation were grown in air and analysed for reductions in GDC proteins and GDC activity. The leaves of heterozygous plants contained reduced amounts of H-protein, and when...
Abstract. Isochorismate hydroxymutase (i.e. isochorismate synthase, EC 5.4.99.6) was purified from an anthraquinone-producing cell-suspension culture of Galium mollugo L. Although attempts to stabilize the labile enzyme met with little success, a substantial increase in enzyme activity was observed in the presence of glycine betaine (500mM). Column chromatography on solid supports other than diethylaminoethyl...
Abstract. The effects of anti-calmodulin (CaM) serum, the CaM antagonist W7-agarose, the Ca2+ chelator ethyleneglycol-bis-(-aminoethyl)-N,N,N,N-tetraacetic acid (EGTA) and exogenous pure CaM on pollen germination and tube growth of Hippeastrum rutilum Herb were studied. Pollen germination and tube growth were inhibited or completely stopped by anti-CaM serum in a dose-dependent manner, while the same...
Abstract. Glutathione (GSH), -glutamylcysteine (-EC) and major free amino acids were measured in darkened and illuminated leaves from untransformed poplars (Populus tremulaP. alba) and poplars expressing Escherichia coli genes for -glutamylcysteine synthetase (-ECS; EC 3.2.3.3) and glutathione reductase (GR; EC 1.6.4.2). In poplars overexpressing -ECS, foliar -EC contents and GSH contents were markedly...
Abstract. The involvement of gibberellins (GAs) and ethylene in the process of root radial expansion was studied in young seedlings of Carrizo citrange [Citrus sinensis (L.) Osb.Poncirus trifoliata (L.) Raf.]. The GA inhibitors cycocel, paclobutrazol, and tetcyclacis enhanced radial expansion of the root tip (up to 2.3-fold) as a result of increases in stele diameter and inner cortex width. The GA...
Abstract. Using the cell pressure probe, the effects of temperature on hydraulic conductivity (Lp; osmotic water permeability), solute permeability (permeability coefficient, Ps), and reflection coefficients (s) were measured on internodes of Chara corallina, Klein ex Willd., em R.D.W.. For the first time, complete sets of transport coefficients were obtained in the range between 10 and 35C which...
Abstract. Oligogalacturonide-induced modifications of protein phosphorylation in cells of Nicotiana tabacumL. were investigated by in-vitro phosphorylation of plasma-membrane-enriched fractions and electrophoretic analysis on two-dimensional gels. About 100 polypeptides were resolved; among these 40 phosphoproteins were detected and their 33P-labelling quantified. Most of the phosphorylations were...
Abstract. The expression of early light-inducible proteins (ELIPs) was analyzed in non-hardened barley (Hordeum vulgare L. cv. Apex) plants which were acclimated to cold (5C) and high-light stress (1500molm2s1) for several days. Severe photoinhibition occurred after some hours in the cold and remained constant during the following days. Lipid peroxidation was observed only under high light in the...
Abstract. Uricase (urate: oxygen oxidoreductase, EC1.7.3.3) from leaves of chickpea (Cicer arietimum L.), broad bean (Vicia faba major L.), and wheat (Triticum aestivum L.) has been purified to electrophoretic homogeneity by a procedure which includes xanthine-agarose affinity chromatography as the main step. Purification factors of 7400083000 and recoveries of 8090% were achieved. Purified preparations...
Abstract. Expression of the polygalacturonase-inhibiting-protein gene (pgip) during development of French bean (Phaseolus vulgaris L. cv. Red Kidney) was analysed in various organs, including leaves, stems and roots of etiolated and light-grown seedlings, light-grown adult plants, as well as flowers, pods, and seeds. In light-grown seedlings and plants, pgip transcripts were detected in all tissues...
Abstract. The regulation by photorespiration of the transcript level corresponding to plastidic glutamine synthetase (GS-2) was investigated in the leaves of Arabidopsis thaliana (L.) Heynh.. Photorespiration was suppressed by growing the plants in an atmosphere containing 300 Pa CO2. Suppression of photorespiration was demonstrated by the ability of the conditionally lethal serine hydroxymethyltransferase...
Abstract. In chicory, we examined how NO3 supply affected NO3 uptake, N partitioning between shoot and root and N accumulation in the tuberized root throughout the vegetative period. Plants were grown at two NO3 concentrations: 0.6 and 3 mM. We used 15N-labelling/chase experiments for the quantification of N fluxes between shoot and root and for determining whether N stored in the tuberized root originates...
Abstract. We examined the role of cytokinins (CKs) in release of apical dominance in lateral buds of chickpea (Cicer arietinum L.). Shoot decapitation or application of CKs (benzyladenine, zeatin or dihydrozeatin) stimulated rapid bud growth. Time-lapse video recording revealed growth initiation within 2h of application of 200pmol benzyladenine or within 3h of decapitation. Endogenous CK content in...
Abstract. Sieve-tube exudate protein (STEP) from Ricinus communis L. seedlings consists of a characteristic set of more than 100 different polypeptides, against which a complex antiserum was raised. This antiserum cross-reacted with dominant protein species (molecular weights 1030kDa) present in the sieve-tube exudate and, to a lesser extent, with proteins in tissue extracts of Ricinus and a wide...
Abstract. The localisation of maize (Zea mays L.) auxin-binding protein (ABP1) has been studied using a variety of techniques. At the whole-tissue level, tissue printing indicated that ABP1 is expressed to similar levels in all cells of the maize coleoptile and in the enclosed leaf roll. Within cells, the signals from immunofluorescence and immunogold labelling of ultrathin sections both indicated...
Abstract. Immature zygotic embryos of six ecotypes (Nd-0, Ler, C24, Col-0, Nossen, Ws-2) of Arabidopsis thaliana (L.) Heynh. were cultured in vitro. The same ecotypes, except Nossen, were used for studies on leaf protoplast culture. Experimental conditions for the induction of somatic embryos were established in both culture systems. In the case of immature zygotic embryos, the parameters investigated...
Abstract. To identify light-regulated genes in Arabidopsis thaliana (L.) Heynh. a clone was isolated which contains a cDNA fragment with sequence similarity to receptor- like protein kinases (RLKs). Sequence analysis of the corresponding genomic DNA as well as determination of transcribed regions revealed that the gene comprises 12 exons. Sections of the deduced polypeptide exhibit homologies with...
Abstract. According to the cohesion theory for the ascent of water in vascular plants, significant tensions should develop in the water columns of transpiring trees. These tensions cause small but detectable changes in the diameter of the xylem as a consequence of adhesive forces between water molecules and the inner xylem walls. The diurnal time course of tension in the water columns in the xylem...
Abstract. Transformed plants of Nicotiana plumbaginifolia Viv. constitutively expressing nitrate reductase (35S-NR) or -glucuronidase (35S-GUS) and untransformed controls were grown for two weeks in a CO2-enriched atmosphere. Whereas CO2 enrichment (1000 ll1) resulted in an increase in the carbon (C) to nitrogen (N) ratio of both the tobacco lines grown in pots with vermiculite, the C/N ratio was...