The role of root exudates in specific apple (Malus × domestica Borkh.) replant disease (SARD)

In an effort to improve our understanding of the specific apple replant disease (SARD), direct and indirect effects of phytohormones and related compounds (abscisic acid, 6‐benzyladenine, indole‐3‐acetic acid, 1‐naphthaleneacetic acid, and gibberellins GA₃ or GA₄) on root exudates of apple seedlings were evaluated as a potential mediating factor in the infection process. In the first type of experiments, radioactively labeled hormonal substances were applied to the stumps of decapitated apple‐seedlings and the occurrence of radioactivity in root exudates and their qualitative characterization were examined (direct influence). In another set of experiments, the effects of leaf‐applied plant growth regulators on the amount and composition of the predominant organic acids, carbohydrates, and amino acids/amides were studied. Cherry seedlings resistant to SARD and apple seedlings with dormant apical buds and, thus, not susceptible to infection were used for comparison. The results showed no differences in exudation of applied plant growth regulators between growing cherry and apple seedlings. Thus, a direct effect of plant hormones on the infection process is unlikely. However, leaf treatments with growth regulators, in particular with auxin‐type compounds and abscisic acid, increased exudation of alditols. This may indicate that plant hormones are, to some degree, indirectly involved in the infection process.     

High seedling recruitment of indigenous tree species in forest plantations in Kakamega Forest,western Kenya

Tree plantations are often used to compensate for the destruction and conversion of natural forests in the tropics. An important question is whether these plantations allow for the regeneration of indigenous tree species and are expected to transform into more natural forests in the future. To evaluate the potential of differently managed forest types for seedling recruitment of indigenous tree species we studied structural characteristics as well as tree and seedling communities in stands of natural forest, different types of tree plantations and secondary forest in Kakamega Forest, western Kenya. Forest types differed considerably in structural characteristics and tree composition with stands of natural forest significantly differing from all other forest types in vertical foliage height diversity and number of late-successional tree species. By contrast, total seedling species richness and number did not differ among the forest types. Yet, number of seedlings of late-successional species decreased from natural forest and plantations of a mixture of indigenous tree species towards monocultures and secondary forests while number of seedlings of early-successional species increased in the same order. A joint Principal Component Analysis (PCA) corroborated higher similarity among seedling communities than among tree communities. Our results indicate a convergence of recruiting seedling communities in different forest management types suggesting that tree plantations might buffer forest loss to a certain extent and may have the potential to develop into more natural forest over time.     

Adverse effects of polymyxin B administration to healthy horses

BackgroundPolymyxin B (PolyB) is used to treat endotoxemia in horses; neurologic and nephrogenic adverse effects occur in humans.ObjectivesTo describe PolyB adverse effects in horses.AnimalsFive healthy horses (ataxia 0/5), 1 horse with cervical osteoarthritis (ataxia 1/5).MethodsProspective blinded randomized cross‐over trial; 3‐weeks wash out. Horses received PolyB (PolyB 6000 IU/kg IV, 7 doses q12h, n = 6) and PolyB/gentamicin (PolyB 6000 IU/kg IV, q12h 7 doses; gentamicin 10 mg/kg IV q24h 4 doses n = 4, or q12‐24 h 5 doses because of an additional erroneous dose, n = 2). Daily neurological examinations were video recorded, and ataxia graded by 3 observers. Urine status, urinary GGT/creatinine ratio, plasma creatinine, and urea were assessed every other day, EMG daily. Mixed model analysis was used to evaluate factors associated with ataxia grade and [PolyB].ResultsMedian ataxia score increased from 0/5 (range 0‐2/5) to 2/5 (range 1‐3/5) during administration and declined to 0.5/5 (range 0‐2/5) after cessation. Gentamicin co‐administration (P < .01, effect size: .8), number of PolyB doses (P < .001, effect size: .6), and time since last PolyB dose (P < .001, effect size: .5) had a significant effect on ataxia grades, while horse, day, [Genta], [PolyB], and [PolyB]_CSF did not. Gentamicin co‐administration and [Genta] C_peak had no effect on median [PolyB] C_peak (4.67 and 4.89 μg/ml for PolyB and PolyB/gentamicin, respectively). Urinary GGT/creatinine ratio was elevated in 3/6 horses receiving PolyB/gentamicin. The EMG remained unchanged.Conclusions and Clinical ImportancePolyB caused transient ataxia, worsening with cumulative PolyB doses and gentamicin co‐administration. Nephrotoxicity of PolyB was only evident when gentamicin was co‐administered.     

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye

OBJECTIVE: To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats. ANIMALS STUDIED: The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size. RESULTS: Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (相似文献   

Quality control of commercially available essential oils by means of Raman spectroscopy

The essential oils of different spices and aroma plants were investigated fast and nondestructively by means of Raman spectroscopy. The main ingredients of these oils, mostly monoterpenes and phenylpropane derivatives, were identified. A hierarchical cluster analysis shows that the oils of the investigated plants cluster chemotaxonomically, which means according to their chemical composition and not according to their botanical degree of relationship. In addition, cross-sections of anise seeds were analyzed applying the Raman mapping technique to localize and investigate the distribution of the oil in situ.     

Comparison of 51chromium-labeled ethylenediamine tetra-acetic acid and iohexol as blood markers for intestinal permeability testing in Beagle dogs

(51)Chromium-labeled ethylenediamine tetra-acetic acid ((51)Cr-EDTA) is the gold standard probe for assessing intestinal permeability (IP) in dogs, but exposure to radioactivity is a disadvantage. Iohexol is a safe contrast medium commonly used for medical imaging purposes and has been successfully applied more recently for the assessment of IP in animal models and humans. This study aimed at comparing (51)Cr-EDTA and iohexol as IP blood markers in dogs. A test solution containing (51)Cr-EDTA and iohexol was administered intragastrically to seven healthy laboratory Beagle dogs, and percentage recoveries in serum were calculated. The strong linear association (correlation, r=0.76 and linear regression, y=0.03+5.04x) between (51)Cr-EDTA and iohexol supports the potential usefulness of iohexol as an IP blood marker in dogs.     

How does the harvest index affect water‐use efficiency and nutrient‐utilization efficiency of sunflowers (Helianthus annuus L.)?

Besides oilseed rape and soybean, sunflower is one of the most important annual oilcrops. Apart from seed yield, which is the most important trait in many crops, oil yield is of utmost interest for sunflower breeders and farmers. Compared to the seed yield of sunflowers, their total biomass is often very high, and it is of great agronomic interest to increase the ratio of both parameters, which is defined as harvest index. With an increase in harvest index, improvements of resource‐use efficiencies can be expected. To generate an adequate seed yield, water and nutrients are key factors and their efficient use becomes increasingly important under conditions of aridity and higher production goals. A pot experiment was conducted in summer 2017 to determine differences in harvest index of various sunflower genotypes which could have an influence on the use efficiencies of water and nutrients (N, P, K). In total, 25 genotypes of different origin and with various morphological traits were investigated under optimal growth conditions. The harvest index varied from 29% to 47% and showed significant differences among some genotypes. The harvest index was less affected by the total biomass of the plants but more by the seed yield. The seed yield itself was mainly determined by the single seed weight rather than by the number of seeds. The experiment also confirmed significant positive correlations between harvest indices and all use efficiencies. Genotypes with high harvest indices were characterized by high oil concentrations in the seeds and particularly by high oil yields. In conclusion, cultivation of sunflower genotypes with high harvest indices most likely results in high water‐use efficiency and high nutrient‐utilization efficiencies as well as in high oil yields.