排序方式： 共有47条查询结果，搜索用时 15 毫秒
41.
M. Neus Anglès Jordi Reguant Ricard Garcia-Valls Joan Salvadó 《Wood Science and Technology》2003,37(3-4):309-320
Lignins were obtained from a mixture of softwood sawdust using a hydrolytic pretreatment and a subsequent soda-anthraquinone delignification/pulping stage. Their potential uses and the effect of the pretreatment conditions on the yield (% of recovered lignin from black liquors) and chemical composition of isolated lignins were evaluated. The severity factor used combined the temperature and time of the hydrolytic process in a single ordinate (Ro). The severity range was modified from log Ro = 2.6 to log Ro = 4.6 and the pulping conditions were constant throughout the experiments. The effect of the cooking time on the chemical composition of precipitated lignins was also studied between 135–170 min for original (non-pretreated) material. Yield, elemental analysis, molecular weight distribution, Fourier transform infrared spectra (FTIR), structure, and the methoxyl and aliphatic/aromatic alcohol content of the various lignins, were compared. 相似文献
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Oluwashola OLANIYAN Neus RODRíGUEZ-GASOL Nathalie CAYLA Eleonor MICHAUD Steve D. WRATTEN 《农业科学学报》2020,19(2):338-349
The potato psyllid Bactericera cockerelli(Hemiptera: Triozidae) has recently emerged as a serious pest of potatoes and other solanaceous crops. It causes direct feeding damage and also vectors Candidatus Liberibacter solanaceaerum(Lso), a pathogen that causes zebra chip disease in potatoes and which potentially costs growers millions of dollars each year. Such producers rely on frequent sprays of pesticides for psyllid control but the results are unsatisfactory and there are negative side effects. The psyllid has spread beyond its native range in southwest US and northern Mexico to Canada, El Salvador, Honduras, Guatemala and Nicaragua via medium to long range dispersal flights perhaps aided by wind currents, and through anthropogenic means. It was accidentally introduced into New Zealand in 2006 and most recently Australia, most likely through the importation of infested plant material. This review summarizes information from studies on the biology, impact and management of B. cockerelli, and highlights the imminent risk of this insect and its associated pathogen invading China, the world's largest producer of fresh potatoes. Development of risk maps leading to increased surveillance, could prevent or delay an incursion and facilitate early detection or eradication should this occur. Long-term management with Lso-tolerant potato cultivars and psyllid control using the parasitic wasp Tamarixia triozae and other natural enemies should be pursued, rather than depending on synthetic pesticides. 相似文献
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N. Baró-Montel N. Vall-llaura J. Usall N. Teixidó M. A. Naranjo-Ortíz T. Gabaldón R. Torres 《Plant pathology》2019,68(7):1381-1393
The secretion of cell wall-degrading enzymes is one of the mechanisms used by necrotrophic fungi to colonize host tissues. However, information about virulence factors of Monilinia spp., the causal agents of brown rot in stone fruit, is scarce. Plant cell walls have three main components that are broken down by fungal enzymes: cellulose, hemicellulose and pectin. In order to identify Monilinia laxa candidate proteins involved in pectin hydrolysis, two in vitro approaches were conducted: (i) phenotypic and ecophysiological characterization of growth of the pathogen at different pHs, in glucose- and pectin-containing solid media for 7 days' incubation; and (ii) expression analysis of genes encoding M. laxa pectin methyl esterases (MlPMEs) and rhamnogalacturonan hydrolases (MlRG-HYDs) after incubation for 0.5, 2, 6, 24 and 48 h in glucose- and pectin-containing liquid media. Phenotypic tests showed the role of carbon source on M. laxa growth rate and aggressiveness, and indicated that pectinases were greatly affected by pH. Gene expression analyses uncovered differences among members of each family of pectinases and between the two families, defining sets of genes expressed at earlier (0.5–6 h) and later (48 h) phases. Notably, the up- or down-regulation of these target genes was carbon source-dependent. Finally, an in vivo study confirmed the synergistic and complementary role that these genes play in the M. laxa–stone fruit pathosystem. Based on these results, it is hypothesized that MlPME2, MlRG-HYD1 and MlRG-HYD2 may be potential virulence factors of M. laxa in the process from infection to colonization. 相似文献
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Neus?Bellí David?Mitchell Sonia?Marín Isabel?Alegre Antonio?J.?Ramos Naresh?Magan Vicente?SanchisEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(3):233-239
Forty vineyards from four wine making regions of Spain were sampled at three different growth stages in 2002 and 2003. The
aim was to study the fungi associated with grapes and their ability to produce ochratoxin A (OTA) on synthetic media. Among
the total mycoflora, 464 (7.7%) and 648 (10.8%) Aspergillus section Nigri (black aspergilli) strains were isolated in 2002 and 2003, respectively, and were classified into three groups: isolates
with uniseriate heads, A. niger aggregate and A. carbonarius. The latter presented the highest percentage of OTA-positive strains (82% in 2002 and 76% in 2003) and produced the highest
levels of toxin (2.5–25 μg g−1). The sampling year, sampling date, the region and their interactions presented significant differences in the number of
black aspergilli isolated. Most black aspergilli were found in 2003 and at harvest. A positive correlation between the number
of black aspergilli found in grapes and the temperature in the field was found. Grapes from 2003, the warmest year, and from
Costers del Segre, the warmest region, were significantly the most contaminated. No significant correlation between black
aspergilli presence and other meteorological factors such as relative humidity or rainfall could be established. Musts from
all the vineyards were also analysed in both years, although no OTA was found in either year. 相似文献
47.
Maria Villarino Beatriz Egüen Neus Lamarca Joan Segarra Josep Usall Paloma Melgarejo Antonieta De Cal 《European journal of plant pathology / European Foundation for Plant Pathology》2013,137(4):835-845
Seventeen field surveys were done in four commercial orchards during six consecutive fruit-growing seasons from 2006 until 2011 in order to determine the current frequencies of occurrence of M. laxa, M. fructigena, and M. fructicola and their relative contributions to postharvest brown rot in peaches and nectarines in the Ebro Valley. The relative frequencies of occurrence of Monilinia spp. were determined on three sources of primary inoculum and on three sources of secondary inoculum. The major relative frequencies of Monilinia spp. were significantly recorded (P?=?0.05) from mummified fruit on the trees (approx. 42 %) and 7-day-old harvested fruit with brown rot (32 %), followed by that recovered from mummified fruit on the orchard bed (14 %), pruned branches on the orchard bed (8 %) and latent infections of immature fruit (3 %). We found that: (a) the relative frequency of M. fructicola has increased over the years to coexist on the same level as at the time M. laxa, (b) M. fructigena is no longer a cause of brown rot in harvested peaches, (c), a progressive reduction in the time of the first appearance of Monilinia airborne conidia (r?=??0.30, P?=?0.003), and the time of the first latent infection (r?=??0.44, P?=?0.0001) was detected along years after correlation analysis, and (d) these displacements are not associated with an increased incidence of brown rot disease. The M. fructicola increase was due to its significantly increased presence in 7-day-old harvested fruit with brown rot (r?=?0.73, P?=?0.0009), in latent infections of immature fruit (r?=?0.68, P?=?0.002), on pruned branches on the orchard bed (r?=?0.56, P?=?0.018), and on mummified fruit sampled on the trees (r?=?0.53, P?=?0.03). This progressive increase was accompanied by a progressive reduction in the relative frequency of occurrence of M. laxa in 7-day-old harvested fruit with brown rot (r?=??0.55, P?=?0.021) and M. fructigena on mummified fruit sampled on the trees (r?=??0.51, P?=?0.03). 相似文献