Blossom‐end rot and fruit cracking of tomato grown in net‐covered greenhouses in Central Thailand can partly be corrected by calcium and boron sprays     

Frank Liebisch  Johannes F. J. Max  Gregor Heine  Walter J. Horst 《植物养料与土壤学杂志》2009,172(1):140-150

Two tomato (Lycopersicon esculentum Mill.) cultivars King Kong 2 (KK2) and FMTT 260 (FMTT) were grown in a net‐covered greenhouse in Central Thailand to investigate the influence of fruit applications of combined aqueous calcium (Ca) and boron (B) solutions amended or not with the tenside Glucopon® on fruit yield and quality. Special attention was paid on blossom‐end rot (BER) and fruit cracking (FC), two prevailing disorders in tomato and main causes for non‐marketability of tomato fruits under the conditions of protected cultivation in Central Thailand. While no effect of the additional Ca and B applications on total fruit yield was observed, the composition of the non‐marketable fraction of fruit yield differed significantly between treatments and cultivars. Cultivar KK2 proved to be highly susceptible to both BER and FC and, therefore, produced less marketable fruits than cv. FMTT. The Ca and B sprays decreased the incidence of BER but increased FC at the same time. Addition of the tenside Glucopon® to the Ca and B solutions did not yield any further advantage. The contrasting effect of the Ca and B sprays on BER and FC resulted in similar levels of non‐marketable fruit yield in the treatments with or without the sprays for both cultivars. The nutrient status in different fruit segments was surveyed during fruit development. The Ca concentration in the distal end of the fruit during the time of rapid fruit growth was correlated with the BER incidence in mature fruits. Since additional Ca and B sprays are labor‐intensive and did not significantly reduce the portion of non‐marketable fruits, the selection of cultivars insusceptible to BER and FC appears to be of highest priority when conditions favoring these disorders are to be expected. This is particularly true for protected cultivation in Central Thailand.  相似文献   

Phylogenetic relationship and genetic differentiation of Populus caspica and Populus alba using cpDNA and ITS noncoding sequences     

Hamed Yousefzadeh  Abasalt Hosseinzadeh Colagar  Effat Yousefi  Maryam Badbar  Gregor Kozlowski 《林业研究》2019,(2):451-461

Populus caspica Bornm.(section Leuce and subsection Albida), one of the most endangered endemic tree species in the Hyrcanian Forest in Iran, has numerous morphological characteristics that are closely similar to Populus alba; to clarify their taxonomic relatedness and genetic differentiation and thus inform conservation strategies, we used the noncoding regions of chloroplast DNA(cpDNA; trnL-F and trnH-psbA) and the internal transcribed spacer(ITS). Leaf samples were collected from six populations across northern Iran. cpDNA and ITS fragments were amplified by universal primers using the PCR technique and directed sequencing. The results showed that P. caspica is genetically differentiated from P.alba, and two ITS variants were detected within some P.caspica individuals. Conflicts between topologies from ITS and plastid genomes were observed. High differentiation of P. caspica from the other Populus species shown in this study confirmed the diverging taxonomic status of this endangered species. We recommend in situ conservation measures(e.g., protected areas) for at least several populations of this species, especially in the plain regions of the Hyrcanian forest.  相似文献   

Relationships between results of the Ortolani method of hip joint palpation and distraction index, Norberg angle, and hip score in dogs   总被引：1，自引：0，他引：1  

Puerto DA  Smith GK  Gregor TP  LaFond E  Conzemius MG  Cabell LW  McKelvie PJ 《Journal of the American Veterinary Medical Association》1999,214(4):497-501

OBJECTIVE: To determine whether results of the Ortolani method of hip joint palpation in dogs were related to distraction index (DI), Norberg angle, or radiographic hip score. DESIGN: Cross-sectional study. ANIMALS: 459 clinically normal dogs. PROCEDURE: Dogs were sedated for radiography and palpation of the hip joints. Results of hip joint palpation were classified as negative, mild positive, moderate positive, or severe positive. Distraction indices were measured for all dogs. Norberg angles were measured for 380 dogs for which ventrodorsal hip-extended radiographic projections were available. Hip scores assigned by the Orthopedic Foundation for Animals (OFA) were available for 95 dogs. RESULTS: Age, weight, and sex were not significantly associated with results of hip joint palpation. There was moderate correlation between results of hip joint palpation and DI (r = 0.636), low-moderate correlation between results of hip joint palpation and OFA hip scores (rs = 0.437), and weak negative correlation (r = -0.236) between results of hip joint palpation and Norberg angle. For joints without degenerative joint disease (DJD), there was a significant linear relationship between results of hip palpation and DI; however, for joint with DJD, there was not. Results of hip joint palpation were 5.3-fold as likely to be negative for dogs with DJD as for dogs without. CLINICAL IMPLICATIONS: Results of hip joint palpation were at best moderately correlated with radiographic measures of hip joint laxity. Therefore, hip joint palpation should be combined with hip-extended and stress radiography when assessing hip joint quality.  相似文献   

Rupture of the bile duct in a dog     

R Borthwick  C P MacKenzie  N D Lewis  W W Gregor 《The Veterinary record》1973,92(14):356-359

  相似文献   

Effects of UV light irradiation on colour stability of thermally modified, copper ethanolamine treated and non-modified wood: EPR and DRIFT spectroscopic studies     

Manabendra Deka  Miha Humar  Gregor Rep  Borut Kričej  Marjeta Šentjurc  Marko Petrič 《Wood Science and Technology》2008,42(1):5-20

A series of experiments were carried out to investigate the colour stability of chemically treated and thermally modified wood compared to non-modified wood during long term artificial UV light irradiation. One set of wood samples was vacuum-pressure impregnated with alkaline (pH 9.8) copper (II) ethanolamine aqueous solution, while another set of samples from the same wood block was thermally modified at 210°C and −0.90 bar for 2 h. The treated and modified wood samples along with the non-modified ones were exposed to artificial UV light with the wave length in the region of UVA (315–400 nm) and UVB (280–315 nm) intermittently for 500 h. Colour measurements were carried out throughout the irradiation period at an interval of 100 h according to CIEL*a*b* system, where the results are presented in terms of ΔE, ΔL*, Δa* and Δb* values. Better photo-stability in terms of colour changes was recorded for both treated and modified woods compared to the non-modified one. By means of EPR and DRIFT spectroscopic study it was shown that some degree of colour stability of treated and modified woods, achieved during artificial UV light irradiation, resulted from lignin modifications and monomers of phenolic compounds.  相似文献   

Evaluation of the Norberg angle threshold: a comparison of Norberg angle and distraction index as measures of coxofemoral degenerative joint disease susceptibility in seven breeds of dogs     

Culp WT  Kapatkin AS  Gregor TP  Powers MY  McKelvie PJ  Smith GK 《Veterinary surgery : VS》2006,35(5):453-459

OBJECTIVE: To evaluate the thresholds of 2 radiographic methods used to determine coxofemoral joint laxity in 7 breeds of dogs. ANIMALS: Three hundred and fifty clinically normal dogs. STUDY DESIGN: Retrospective study. METHODS: Hip radiographs from 7 breeds of dogs were randomly selected from a database. None of the dogs had radiographic evidence of degenerative joint disease (DJD). Distraction index (DI) and Norberg angle (NA) were measured on these radiographs and compared with DI and NA thresholds for diagnosing DJD susceptibility derived from the literature and from evaluated Borzois. Dogs with a NA<105 degrees and a DI of < or =0.32 were considered false-positives and dogs with a NA> or =105 degrees and a DI of >0.32 were considered false-negatives. RESULTS: Mean age of all dogs was 22.9 months. Mean NA for all dogs was 99.37 degrees, and mean DI for all dogs was 0.44. Borzoi mean DI of was significantly less than the mean DI of the other 6 breeds. The highest (most hip laxity) Borzoi DI was 0.32, and the lowest (most hip laxity) Borzoi NA was 99 degrees. False-positive and false-negative diagnoses were identified in 6 of the 7 breeds. CONCLUSIONS: Using the NA threshold of 105 degrees (literature established threshold of susceptibility to DJD) resulted in a high percentage of false-negative and false-positive diagnoses. Breeds like the Labrador Retriever and Rottweiler would have large numbers of hip dysplasia susceptible dogs remain in the breeding population based on this NA threshold. False-positive diagnoses were common in breeds like the Australian Shepherd, Borzoi, and German Shepherd effectively eliminating hip dysplasia nonsusceptible dogs from the breeding population. CLINICAL RELEVANCE: The NA was not an accurate predictor of DJD susceptibility in these 7 breeds of dogs when using a NA threshold of 105 degrees.  相似文献   

Effect of <Emphasis Type="Italic">Meloidogyne ethiopica</Emphasis> parasitism on water management and physiological stress in tomato     

Polona Strajnar  Saša Širca  Gregor Urek  Helena Šircelj  Peter Železnik  Dominik Vodnik 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):49-57

Root-knot nematodes (RKN) are obligate endoparasites that severely damage the host root system. Nutrient and water uptake are substantially reduced in infested plants, resulting into altered physiological processes and reduced plant growth. The effect of nematode infestation on the morphological changes of roots and subsequent physiological plant responses of infested tomatoes with the RKN Meloidogyne ethiopica was studied in a pot experiment. Plants were infested with two inoculum densities (10 or 50 eggs per cm³ substrate) and its effect was evaluated 74 and 102 days post inoculation (DPI). Morphological changes and root growth was determined by analysing scanned images of the whole root system. Nematode infestation reduced the portion of fine roots and increased that of coarse roots due to gall formation. Fine roots of non-infested control plants represented around 51% of the area of the whole root system at 74 and 102 DPI. In comparison to controls, plants inoculated with low and high nematode density had 2.1 and 3.2-times lower surface area of fine roots at 102 DPI. Root analyses revealed that plants had a very limited ability to mitigate the effects of the root-knot nematodes infestation by altering root growth. Root galls had a major influence on the hydraulic conductivity of the root system, which was significantly reduced. The low leaf water potential of infested plants coincided with decreased stomatal conductivity, transpiration and photosynthesis. The latter two were reduced by 60–70% when compared to non-infested control plants.  相似文献   

Changes in soil microbial and nematode communities during ecosystem decline across a long-term chronosequence     

Wendy M. Williamson  David A. Wardle  Gregor W. Yeates 《Soil biology & biochemistry》2005,37(7):1289-1301

Following the creation of new land surfaces, there is an initial build-up phase, but in the prolonged absence of catastrophic disturbance an ecosystem decline phase has often been observed. While a number of studies have investigated the changes in soil biota that occur during the build-up phase, few studies have investigated how the soil food web changes during the ecosystem decline phase, even though such studies may assist our understanding of biotic factors that contribute to long-term ecosystem changes. We investigated the response of soil microbial and nematode communities to ecosystem decline by studying each of four stages of a long-term (280,000 year) forested chronosequence caused by uplift of marine terraces in the Waitutu region of Fiordland National Park, New Zealand. With increasing chronosequence age there were large increases in ratios of C to N, C to P, and N to P in both the organic layer and mineral soil layer, indicative of greater nutrient (notably P) limitation over time. Variables related to soil microbial biomass and activity were lower on the older terraces when expressed on a per unit soil C basis, reflecting that the quality of the soil organic matter, which is the resource that supports microbial metabolism, declined over time. This in turn had important consequences for population densities of soil nematodes and enchytraeids, including both microbe-feeding and predatory groups. There were significant increases in the fungal:bacterial biomass ratio and in the fungal-feeding:bacterial-feeding nematode densities. Taken collectively, our results suggest a decline in soil microbial activity and soil fauna, and an increase in the relative importance of the fungal-based (vs. bacterial-based) energy channel during long-term ecosystem development on terraces of marine origin. This corroborates the hypothesis that the studied sites represent a retrogressive shift in soil organic matter quality over a long-term chronosequence.  相似文献   

Influence of three invasive weeds and site factors on soil microfauna in New Zealand     

Gregor W. Yeates  Peter A. Williams 《Pedobiologia》2001,45(4):367

  相似文献   

Spatial variability of sequentially extracted P fractions in a silty loam     

Elena Heilmann  Peter Leinweber  Gregor Ollesch  Ralph Meißner 《植物养料与土壤学杂志》2005,168(3):307-315

  相似文献