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Barley Seedlings (barley + seedling)
Selected AbstractsFusarium culmorum Infection of Barley Seedlings: Correlation between Aggressiveness and Deoxynivalenol ContentJOURNAL OF PHYTOPATHOLOGY, Issue 6 2002HELLE HESTBJERG Fusarium culmorum is a serious plant pathogen, especially on cereals. The production of deoxynivalenol (DON) by F. culmorum is believed to play a role in pathogenesis. This relationship has been almost exclusively studied in connection with head blight. The present paper reports the first finding of DON in cereal seedlings infected with F. culmorum. A pathogenicity test was performed, including 70 isolates of this pathogen from different sites within northern and central Europe. All isolates caused disease on barley seedlings. For 15 isolates with varying aggressiveness, the DON content in the 19-day-old-barley seedlings was determined. There was a significant correlation between DON concentration and disease index. The aggressiveness of two outlying isolates with very low DON production is discussed. The results indicate that for F. culmorum isolates of the DON chemotype, production of this toxin influences the aggressiveness of the isolates towards barley seedlings. [source] Screening for resistance in the primary and secondary gene pool of barley against the root-lesion nematode Pratylenchus neglectusPLANT BREEDING, Issue 5 2009T. Keil Abstract Root-lesion nematodes of the genus Pratylenchus are significant pests in crop cultivation throughout many parts of the world. A study was initiated to determine the resistance of Hordeum vulgare and H. vulgare ssp. spontaneum (wild barley) against one major representative of the genus Pratylenchus, P. neglectus. A glasshouse test was first established. Barley seedlings were grown in 20 cm3 tubes filled with sand. Each plant was inoculated with 400 P. neglectus juveniles. After 12 weeks of cultivation nematodes were isolated from roots and sand using a misting chamber. The nematodes were counted under a microscope. A representative collection of 565 barley and wild barley accessions was tested in this way. The average number of nematodes per accession ranged from 350 to 12 000. In a verification experiment, 35 accessions with low and high infection rates were tested. This experiment identified a number of accessions with low infection rates. The perspectives for future breeding of barley cultivars resistant to root-lesion nematodes are discussed. [source] Identification of barley mutants in the cultivar ,Lux' at the Dhn loci through TILLINGPLANT BREEDING, Issue 4 2009S. Lababidi Abstract TILLING is a reverse genetic strategy that allows screening for mutations in genes with known sequences in a plant mutant population. A TILLING population has been developed for the Danish barley variety ,Lux' (Hordeum vulgare L.), by using sodium azide to induce mutations. Scoring of four visible phenotypic characters of barley seedling in reference to the parental cultivar ,Lux' in the M3 plants showed over 3.5% lethality. A series of pool ratios of mixed DNA from mutant lines were tested and 10-fold pools appeared to be the practical mixing ratio for the detection of fragments in the 500,700 bp range. Two of the 13 known dehydrin genes, Dhn12 and Dhn13, respectively, were examined and five independent missense mutations were obtained from a population of 9575 barley mutant plants. This corresponds to a mutation density of approximately one mutation every two and half million base pairs for these two genes. The mutant population of approximately 10 000 lines was screened for mutations in two genes in a short time due to high pooling ratio. [source] Fusarium culmorum Infection of Barley Seedlings: Correlation between Aggressiveness and Deoxynivalenol ContentJOURNAL OF PHYTOPATHOLOGY, Issue 6 2002HELLE HESTBJERG Fusarium culmorum is a serious plant pathogen, especially on cereals. The production of deoxynivalenol (DON) by F. culmorum is believed to play a role in pathogenesis. This relationship has been almost exclusively studied in connection with head blight. The present paper reports the first finding of DON in cereal seedlings infected with F. culmorum. A pathogenicity test was performed, including 70 isolates of this pathogen from different sites within northern and central Europe. All isolates caused disease on barley seedlings. For 15 isolates with varying aggressiveness, the DON content in the 19-day-old-barley seedlings was determined. There was a significant correlation between DON concentration and disease index. The aggressiveness of two outlying isolates with very low DON production is discussed. The results indicate that for F. culmorum isolates of the DON chemotype, production of this toxin influences the aggressiveness of the isolates towards barley seedlings. [source] Short episodes of water stress increase barley root resistance to radial shrinkage in a dehydrating environmentPHYSIOLOGIA PLANTARUM, Issue 4 2006Jorge Hugo Lemcoff Although plant shoots can be ,hardened' by abiotic stresses, little is known about such changes in roots. In order to investigate possible induction of root-hardening in response to short water-stress episodes, barley seedlings (Hordeum vulgare L) hydroponically grown under a controlled environment were moderately water-stressed by addition of a non-penetrating osmoticum, polyethylene glycol (PEG) 6000 at ,0.4 MPa water potential, to the aerated nutrient solution. Seedlings were then hydrated in dilute nutrient solution without PEG before excision and assay of the seminal roots. Previous water stress treatments for 72 h, 12 h, or even 6 h induced an apparent root-hardening process. Thus, root radial shrinkage during subsequent exposure to strongly dehydrating conditions was remarkably decreased. The root hardening was related to biophysical adjustments: turgor-pressure increased while osmotic potential decreased from ,0.45 ± 0.02 MPa to ,0.60 ± 0.02 MPa. Moreover, the maximum bulk volumetric modulus of elasticity, ?max determined by pressure,volume analysis, increased from 2.1 ± 0.4 MPa to 3.7 ± 0.4 MPa, i.e. root elasticity was decreased. Root hardening in response to episodes of water stress may have ecological significance for barley plants in regions where intermittent drought episodes are frequent. [source] Barley polyamine oxidase: characterisation and analysis of the cofactor and the N-terminal amino acid sequencePHYTOCHEMICAL ANALYSIS, Issue 3 2001Anna Radová Abstract This paper reports the first purification method developed for the isolation of an homogeneous polyamine oxidase (PAO) from etiolated barley seedlings. The crude enzyme preparation was obtained after initial precipitation of the extract with protamine sulphate and ammonium sulphate. The enzyme was further purified to a final homogeneity (by the criteria of isoelectric focusing and SDS,PAGE) using techniques of low pressure chromatography followed by two FPLC steps. The purified yellow enzyme showed visible absorption maxima of a flavoprotein at 380 and 450,nm: the presence of FAD as the cofactor was further confirmed by measuring the fluorescence spectra. Barley PAO is an acidic protein (pI 5.4) containing 3% of neutral sugars: its molecular mass determined by SDS,PAGE was 56,kDa, whilst gel permeation chromatography revealed the higher value of 76 kDa. The N-terminal amino acid sequence of barley PAO shows a high degree of similarity to that of maize PAO and to several other flavoprotein oxidases. The polyamines spermine and spermidine were the only two substrates of the enzyme with Km values 4,×,10,5 and 3,×,10,5,M and pH optima of 5.0 and 6.0, respectively. Barley polyamine oxidase is markedly inhibited by acridine dyes and hydrazines. Weak inhibition was observed with substrate analogues, aminoaldehydes, metal chelating agents and several other compounds. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||