Influence of Cation Proportions of the Nutrient Solution on Tipburn Incidence in Strawberry Plants

To determine their influence on leaf tipburn incidence and yields six nutrient solutions with different proportions of potassium (K), calcium (Ca), and magnesium (Mg) were tested in ‘Camarosa’ strawberry plants. Response models were made to predict tipburn incidence, yields and fruit weight. A high Ca proportion in the nutrient solution was determinant for high yields in the first season, while a high Mg content was fundamental for high marketable yields during the two last seasons. In 2001 and 2002, the average fruit weight was higher with high Mg levels, and in 2000 the lowest fruit weights coincided with low levels of Ca in the nutrient solution. The models for tipburn incidence in 2000 and 2002 indicated that solutions with intermediate to high levels of Mg and intermediate to low levels of Ca resulted in a more frequent incidence of tipburn. Conversely, in 2001, the highest tipburn incidence appeared with high K contents.     

ADVERSE EFFECTS OF HUMIC SUBSTANCES FROM DIFFERENT ORIGIN ON LUPIN AS RELATED TO IRON SOURCES

Humic substances improve the efficiency of different iron (Fe) sources overcoming Fe deficiency chlorosis of plants. However, applied at high rates, they can promote negative effects on plants. The main objective of this work was to study the potential adverse effect of three humic acids from different origin when they were applied with two effective Fe sources for plants: Fe- ethylenediaminedihydroxyphenylacetic acid (EDDHA) and Vivianite. To this end, an experiment with lupin (Lupinus albus L.) was performed involving two factors: (i) Fe source, and (ii) humic substances from three different origin (composted cork, leonardite, and compost obtained from a mixture of olive husk with cotton gin trash) applied at 0, 0.1, and 0.5 g organic carbon (C) kg^?1 of growing media. At the rates used, humic substances promoted adverse effects on plant development, chlorophyll meter readings, and Fe content in lupin grown in calcareous media. Overall, the effect on dry matter and Fe content in plants was more relevant when Fe was supplied with Vivianite, the effect on chlorophyll meter readings being more significant when Fe was applied as Fe-EDDHA. Differences were also observed depending on the source of humic substances, those from leonardite promoting the greatest decrease in dry matter in roots and shoots. These humic substances possessed the highest values of spectroscopy index for aromaticity (A₂₅₄ ). On the other hand, the application of humic substances from olive husk compost, which exhibited the lower aromaticity index, resulted in the smallest decrease in dry matter production and chlorophyll meter readings. Dry matter in roots decreased logarithmically with increased values of the estimates of the amounts of aromatic compounds accumulated in the growing media (R² = 0.92; P < 0.01) with Vivianite as Fe source. Thus, the effects decreasing dry matter production, particularly in roots, and chlorophyll meter readings can be ascribed at least partially to the presence of phytotoxic aromatic compounds in humic substances.     

RESPONSE OF FRIJOLILLO RHYNCHOSIA MINIMA (L) DC. TO SUPPLEMENTARY PHOSPHORUS WITH THREE SOIL MOISTURE CONDITIONS: II. SOLUTE ACCUMULATION

The objective of this study was to evaluate the effects of induced drought conditions and phosphorous (P) application on osmotic adjustment as reflected in the accumulation of organic solutes in the leaves of frijolillo. The experiment took place under greenhouse conditions without climate control. Plastic containers were used measuring 20 cm high × 15 cm in diameter. In each container, five plants were evaluated from emergence to vegetative growth phase. Three soil moisture regimes were evaluated (25%, 50%, and 100% of field capacity) combined with four concentrations of phosphorous (0, 50,100 and 150 mg kg^?1 of soil). A completely randomized block design with a factorial arrangement of 3×4 with four replications was used. The cellular osmotic adjustment as a response to drought stress in frijolillo was associated with the accumulation of sugars, amino acids and proline in that higher concentrations than the control were measured with moisture at 25%. Concentrations of chlorophyll and carotene increased as soil moisture levels decreased.     

Physiological changes and defense mechanisms induced by cadmium stress in maize

Heavy metals such as cadmium (Cd) enter the ecosystem chiefly as the result of human activities. Nowadays the heavy‐metal pollution of the soil is causing ever greater problems, exacerbated by the fact that the heavy metals accumulated in plants may, either directly or indirectly, find their way into animals and human beings. Maize is one of the world's most important crops, ranking third after wheat and rice, so the changes induced by one of the most toxic heavy metals, Cd, in maize plants is a cause of some concern. This review discusses not only the toxic symptoms caused by Cd stress, but also the tolerance mechanisms activated in the plants. Cadmium induces a number of physiological changes, such as growth inhibition, changes in the water and ion metabolism, the inhibition of photosynthesis, changes in enzyme activities, and the formation of free radicals. The synthesis and compartmentalization of phytochelatins is induced shortly after the initiation of Cd stress, while other defense mechanisms also play an important role.     

Study of gastrointestinal parasites in water buffalo (Bubalus bubalis) reared under Mexican humid tropical conditions

Tropical Animal Health and Production - The objective was to determine the frequency of gastrointestinal parasites (GP) genera affecting water buffalo (Bubalus bubalis) reared under humid tropical...     

Correlation of ultrasonographic and patho-morphological findings in canine hepatic diseases

Findings of hepatic ultrasonography were analysed in 22 dogs with liver disease and compared with the results of final morphological diagnoses. Ultrasonographic appearance of the liver demonstrated focal alterations in 11 dogs (50 per cent): multifocal lesions in hepatic neoplasia (six), hepatic cirrhosis (one), generalised mycosis (one) and unifocal lesions in haemangiosarcoma (one), nodular hyperplasia (one) and misdiagnosed intestinal invagination (one), Diffuse ultrasonographic alterations were found in 11 dogs (50 per cent): hyperechoic liver of normal/enlarged size in lymphosarcoma (four) and hepatic lipidosis (two); hyperechoic ‘bright’ but small liver in atrophic cirrhosis (two); hypoechoic to normal intensity liver of normal size in liver dystrophy (two) and hepatic venous distension (one). Gallbladder abnormalities were detected in 14 of 20 dogs (70 per cent). Correct ultrasonographic diagnoses were made in 11 dogs (50 per cent). The best results were achieved by combining the clinicolaboratory and ultrasonographic findings, providing a correct diagnosis in 17 dogs (77-3 per cent).     

Porcine salivary analysis by 2-dimensional gel electrophoresis in 3 models of acute stress: A pilot study

The purpose of this research was to study changes in the salivary proteome of healthy pigs in stressful situations to identify any potential new salivary biomarker of stress. Three groups of animals were subjected to 3 stress models: snaring restraint followed by simulated sampling of vena cava blood; brief transport by road; and restriction of movement in a digestibility cage. Saliva was obtained from each animal before and 15 and 30 min after the induction of stress. The samples from the animals that showed the greatest increase in salivary cortisol concentration were pooled and run on 2-dimensional gels. Coomassie Brilliant Blue R-250 was used for spot detection and mass spectrometry for spot identification. Statistical analyses showed that 2 proteins had significant differences in expression before and after the induction of stress. These proteins were identified as odorant-binding protein and fragments of albumin. Further studies will be necessary to confirm the value of using these proteins as salivary biomarkers of stress in pigs.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Influence of long-term vaccination of a breeding herd of pigs against PCV2 on reproductive parameters

The objective of the study was to evaluate an efficacy of sows vaccination protocols in the herd with serious problems affecting efficacy of reproduction. The study was performed in a large pig herd with about 1200 sows. Before vaccination against PCV2, farrowing rate in this farm was about 65%. Sows, boar and replacement gilts were immunized using Circovac vaccine (Merial, France) according to producer's recommendations. Parameters of production were analyzed since 2007 until 2010 in selected batches of sows inseminated at the same weeks of the year (17th, 18th, 19th and 20th) to eliminate seasonal variability. In total, 940 sows were subjected to the study. No significant changes in management during these years were introduced. The applied protocol of sow herd long-term vaccination proved to be very efficient. All measured production parameters: reproduction rate, number of piglets born alive, birth weight of piglets and number of piglets weaned per a litter improved after implementation of immunization program. Moreover, further improvement was observed with vaccination in the following reproduction cycles. The most spectacular effect of vaccination regarded average farrowing rate that increased from 64.76% in control group to 86.93% after basic vaccination. Two years after implementation of vaccination program this parameter reached 93.6%. Number of piglets weaned per sow per a litter improved from 10.31 to 11.74 after one year of vaccination and remained relatively stable through the following year. Simultaneously, the percentage of newborn piglets with birth weight < 1 kg decreased significantly (p < 0.05). To summarize, vaccination against PCV2 influenced positively the insemination rate, number of piglets born alive and weaned per litter as well as birth body weight and percentage of piglets weighing < 1 kg.