Enhancement of plant stem growth by flocculation of the antibiotic-producing bacterium, Pseudomonas fluorescens S272, on the roots. (1/34)

The antibiotic-producing bacterium, Pseudomonas fluorescens, is assumed to be important in protecting plants from soilborne diseases. S. fluorescens S272, a hyper-producing strain of pyoluteorin (PT) and 2,4-diacetylphloroglucinol (DG), had previously been isolated from soil. The present paper reported that the growth of water-cultivated Kaiware radish was promoted to 120-140% of its normal level by the coaddition of an S272 culture broth (0.01-1% v/v) and a polysaccharide flocculant (1-100 ppm) from Klebsiella pneumoniae H12. Tight adhesion of S272 cells to the root tissue was microscopically observed. The growth promotion is assumed to have been caused by antibiotic effects for the following two reasons: 1) PT (4 mg/l) and DG (24 mg/l) addition to a radish culture enhanced stem growth to 130% of the normal level; 2) a culture solution containing the S272 culture broth (0.01-1% v/v) markedly inhibited the decomposition of hypersensitive chrysanthemum leaves. A soil-cultivation experiment with Gomphrena globosa under natural conditions also exhibited enhanced stem length (160%) by coaddition of the S272 culture broth and H12 polysaccharide. These results suggest that polysaccharide-enhanced adhesion of P. fluorescens S272 cells might be useful for promoting plant growth through the increased antibiotic effect.  (+info)

Identification of L-inositol and scyllitol and their distribution in various organs in chrysanthemum. (2/34)

Two unidentified soluble carbohydrates were isolated from chrysanthemum (Dendranthema x grandiflorum (Ramat.) Kitamura) leaves using HPLC. The compounds were identified as 1 L-chiro-inositol, called L-inositol (1) and scyllo-inositol, called scyllitol (2) from the results of 1H-NMR, 13C-NMR, and CI-MS spectra. L-Inositol and scyllitol were distributed in four cultivars tested. L-Inositol concentration of petals gradually decreased during the flower bud development, but the L-inositol content increased by about 7 times. Scyllitol was detected only at an early stage of flower bud.  (+info)

Fluid ionic composition influences hydraulic conductance of xylem conduits. (3/34)

The direct effect of fluid composition on xylem hydraulic conductance is investigated in excised stem segments of chrysanthemum (Dendranthema x grandiflorum Tzvelev cv. Cassa) plants. Dynamic changes in hydraulic conductance are accurately measured at 30 s intervals before and after modifications of the composition of the standard fluid (deionized water). It is investigated whether osmotic properties of the flowing solution influence overall hydraulic conductance by affecting the hydraulic conductance of vessel-to-vessel pit membranes, as has previously been suggested. Various iso-osmotic salt solutions (20 mOsm kg-1) of different composition raised the hydraulic conductance of 20 cm long stem segments approximately 5-8% compared to deionized water. In contrast, carbohydrate solutions with similar osmotic strength and pH did not cause any change in hydraulic conductance. KCl solutions that greatly differed in osmotic strength all increased hydraulic conductance, but the response was not correlated with the osmotic strength of the solution. Increasing the number of vessels that were open from one cut end to the other by shortening the stem segments greatly increased the hydraulic conductance response. Changing from deionized water to a salt solution caused an immediate increase in hydraulic conductance, while a shift back to deionized water resulted in a slow decline. This decline lasted longer when the salt solution contained divalent cations compared to monovalent cations. It is concluded that the presence of cations and not the osmotic strength in the flowing solution influenced the hydraulic conductance. The phenomenon is not caused by the vessel-to-vessel pit membranes, which in fact suppressed the effect, due to their large contribution to the overall resistance to water flow.  (+info)

Analysis of bacterial communities in the rhizosphere of chrysanthemum via denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA as well as DNA fragments coding for 16S rRNA. (4/34)

The effect of developing chrysanthemum roots on the presence and activity of bacterial populations in the rhizosphere was examined by using culture-independent methods. Nucleic acids were extracted from rhizosphere soil samples associated with the bases of roots or root tips of plants harvested at different stages of development. PCR and reverse transcriptase (RT) PCR were used to amplify 16S ribosomal DNA (rDNA) and 16S rRNA, respectively, and the products were subjected to denaturing gradient gel electrophoresis (DGGE). Prominent DGGE bands were excised and sequenced to gain insight into the identities of predominantly present (PCR) and predominantly active (RT-PCR) bacterial populations. The majority of DGGE band sequences were related to bacterial genera previously associated with the rhizosphere, such as Pseudomonas, Comamonas, Variovorax, and Acetobacter, or typical of root-free soil environments, such as Bacillus and Arthrobacter. The PCR-DGGE patterns observed for bulk soil were somewhat more complex than those obtained from rhizosphere samples, and the latter contained a subset of the bands present in bulk soil. DGGE analysis of RT-PCR products detected a subset of bands visible in the rDNA-based analysis, indicating that some dominantly detected bacterial populations did not have high levels of metabolic activity. The sequences detected by the RT-PCR approach were, however, derived from a wide taxonomic range, suggesting that activity in the rhizosphere was not determined at broad taxonomic levels but rather was a strain- or species-specific phenomenon. Comparative analysis of DGGE profiles grouped all DNA-derived root tip samples together in a cluster, and within this cluster the root tip samples from young plants formed a separate subcluster. Comparison of rRNA-derived bacterial profiles showed no grouping of root tip samples versus root base samples. Rather, all profiles derived from 2-week-old plant rhizosphere soils grouped together regardless of location along the root.  (+info)

In planta expression of a protein encoded by the extrachromosomal DNA of a phytoplasma and related to geminivirus replication proteins. (5/34)

A new extrachromosomal DNA, EcOYW1, was cloned from the onion yellows phytoplasma (OY-W). Southern blot and PCR analysis showed that EcOYW1 is not present in the OY-M, a mild symptom line derived from OY-W. We determined the complete nucleotide sequence of EcOYW1; it is a circular dsDNA of 7.0 kbp in length, which contains seven ORFs. ORF1 encoded a homologue of the geminivirus Rep protein. Western immunoblot analysis revealed that this Rep homologue is expressed in OY-W infected plants, suggesting that EcOYW1 replicates via a geminivirus-like rolling-circle replication mechanism. EcOYW1 is the first phytoplasmal extrachromosomal DNA shown to express encoded genes.  (+info)

Stability and bioavailability of antioxidants in garland (Chrysanthemum coronarium L.). (6/34)

The stability and bioavailability of the major antioxidants in garland (Chrysanthemum coronarium L.), chlorogenic acid, 3,5-dicaffeoylquinic acid and 4-succinyl-3,5-dicaffeoylquinic acid, were investigated together with caffeic acid. These compounds were stable in artificial digestive juice, but more than 90% of them disappeared from plasma within 30 min after intravenous injection into rats. When they were orally administered, only caffeic acid could be detected.  (+info)

Xylem hydraulic conductivity related to conduit dimensions along chrysanthemum stems. (7/34)

The stem xylem conduit dimensions and hydraulic conductivity of chrysanthemum plants (Dendranthema x grandiflorum Tzvelev cv. Cassa) were analysed and quantified. Simple exponential relations describe conduit length distribution, height dependency of conduit length distribution, and height dependency of stem hydraulic conductivity. These mathematical descriptions can be used to model the xylem water transport system. Within a chrysanthemum stem of 1.0 m, the conduit half-length (the length within which 50% of the conduits have their end) was 0.029 m at soil surface and decreased by half at a height of 0.6 m. With each 0.34 m increase in height up the stem, the hydraulic conductivity decreased by 50%. The resistance calculated from conduit lumen characteristics was 70% of the measured resistance. The remaining unexplained part of the hydraulic resistance is at least partly caused by inter-conduit connections.  (+info)

Method development and validation of a high-performance liquid chromatographic method for pyrethrum extract. (8/34)

A robust analytical methodology is developed for the quantitative determination of all six insecticidal components of pyrethrum extract: jasmolin I, cinerin I, pyrethrin I, jasmolin II, cinerin II, and pyrethrin II. This method, based on the separation technique normal-phase high-performance liquid chromatography, offers selectivity, accuracy, precision, linearity, range, ruggedness, and robustness as well as efficiency and ease.  (+info)

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