Sap flow in papaya plants: Laboratory calibrations and relationships with gas exchanges under field conditions

In papaya plants a study to quantify the water flow through the trunk is important for to promote a good water management in commercial orchard. The objective was to study the relationship between water flow through the trunk and temperature measurements determined by probes inserted in the papaya plant stem in laboratory. In addition, was possible to study the relationship between sap flow and instantaneous gas exchange in field conditions. We constructed an instrument that maintained a stable water flux through a 0.30 m stem section with a constant pressure, simulating the xylem sap flow through the stem. Water flux was adjusted by varying pressure of water in the stem section. The mathematical model used to fit the relation between K (Granier heat coefficient) values and sap flow density was the exponential model: u = 0.5511 × K^1.9104. Field studies was conducted in a commercial orchard located in North of the State of Rio de Janeiro, with 12 plants in October 2002, and eight plants in January 2003. We verified that instantaneous transpiration, measured by a portable system of gas exchange (porometry), presented a good (R² = 0.75) positive relationship with xylem sap flow. Estimates of papaya sap flow can be obtained by scaling portable photosynthesis system measurements with exposed leaves, however the relationship is non-linear in higher instantaneous transpiration rates. The causes of the non-linear relationship in higher transpiration are discussed. In addition, was possible to obtain a good (R² = 0.76) relationship between net photosynthesis rate and xylem sap flow in papaya field-grown.     

Molecular systematics in Chrysanthemum × grandiflorum (Ramat.) Kitamura

An attempt was made to understand the molecular systematics and genetic differences between 10 original chrysanthemum cultivars and 11 mutants. The similarity among the cultivars and mutants varied from 0.17 to 0.90 using RAPD analyses, a simple but efficient method to distinguish cultivars and to assess parentage. Two distinct groups were found. Two cultivars were present as a separate group showing differences from all other cultivars. Mutants with different flower colour could be identified at the molecular level using RAPD technique holding promise to identify unique genes as SCAR markers. A high genetic distance among the different chrysanthemums showed that there exists a possibility of introgressing new and novel genes from the chrysanthemum gene pool.     

Reaction of cucurbits species to infection with Zucchini lethal chlorosis virus

Zucchini lethal chlorosis virus (ZLCV) is a tospovirus that infects species of cucurbits in Brazil and is transmitted by the thrips Frankliniella zucchini. The purpose of the present work was to evaluate the reaction of seven species of cucurbits to infection with ZLCV under field and greenhouse conditions in Piracicaba County, SP. In the field experiment, ZLCV infection occurred naturally. In the greenhouse, plants were mechanically inoculated with ZLCV at the cotyledonal stage. Evaluations were based on symptoms expression and detection of the virus by PTA-ELISA. The percentages of infected plants for field and greenhouse assays, respectively, are indicated in parenthesis for each species/cultivar: Cucurbita pepo var. Caserta (72.9 and 70.7); C. maxima var. Alice (16.0 and 10.4); C. maxima var. Exposição (0.0 and 0.0); C. moschata var. Menina Brasileira (29.2 and 18.2); C. maxima × C. moschata hybrid Takaiama (63.4 and 42.7); Citrullus lanatus var. Crimson Sweet (25.0 and 25.0); Cucumis sativus var. Safira (14.3 and 41.2); and C. anguria (21.4 and 22.7).     

Pericarp total protein profiles as molecular markers of tomato fruit quality traits in two segregating populations

The tomato fruit quality results of biochemical and physiological changes that occur during the ripening process. Although, the pericarp total protein profiles are less polymorphic than DNA-based markers the polymorphism in those could be directly associated with fruit quality traits. The aim of this work was to identify associations between polymorphic polypeptides from fruit pericarp at two ripening stages and fruit quality traits evaluated in two segregating populations of tomato. A cross between a normal ripening cultivar of Solanum lycopersicum (C, Caimanta) and a genotype carrying the nor (non ripening) gene (N) as well as a cross between Caimanta and a cherry type tomato of S. lycopersicum var. cerasiforme (Ce) showed genetic variance for several fruit quality traits such as fruit weight, shape, solids soluble content, acidity, color and fruit shelf life. The quantitative variations observed at phenotypic level had correspondence with the polymorphism detected in the protein profiles. Indeed, the polymophic polypeptides associated with quality fruit traits and fruit shelf life would be useful to assist tomato breeding programs as protein molecular markers.     

Characterization of semen collected by pharmacologically induced ejaculation from a stallion with seminal vesiculitis

The present study compared the quality of sperm collected by artificial vagina or pharmacologically induced ejaculation from a 10-year-old thoroughbred stallion with seminal vesiculitis. The pharmacological protocol involved intravenous administration of detomidine (0.01 mg/kg) and oxytocin (20 IU) and successfully induced ejaculation in all attempts of semen collection. Sperm motility, plasma membrane and acrosome integrity (PMAI), reactive oxygen species (ROS) levels, polymorphonuclear neutrophil (PMN) percentage, and bacterial profiles of fresh and cooled semen (5°C for 24 hr) were evaluated. Semen obtained by the pharmacological method presented reduced seminal volume, decreased PMN percentage and superior sperm motility in cooled samples. Moreover, higher PMAI and lower ROS levels were observed in semen collected by the pharmacological method. Therefore, pharmacologically induced ejaculation is an alternative to obtain semen with minimal contamination and with sperm of superior quality and longevity from stallions with seminal vesiculitis.     

Electro-acupuncture and Chinese herbs for treatment of cervical intervertebral disk disease in a dog

A non-ambulatory dog with tetraparesis following a pain episode that had evolved over 2 months was submitted for medical treatment and diagnosed with intervertebral disk disease at C3-C4 and dorsal extradural compression at C1-C2 and C3-C4 using myelography and computed tomography. The dog experienced ambulation recovery after 15 days of treatment with only electroacupuncture and Chinese herbal medicine, with marked improvement occurring after only 10 treatments. Six months of follow-up demonstrated that the dog was stable and had no recurrence of symptoms. Therefore, it was concluded that the combination of electroacupuncture and Chinese herbal medicine was responsible for motor rehabilitation.     

Effects of α-tocopherol and Ascorbic Acid on Equine Semen Quality after Cryopreservation

This study investigated the effects of ascorbic acid and α-tocopherol supplementation on semen quality parameters of equine thawed-frozen semen. Semen was divided in seven different treatments in a final concentration of 100 × 10⁶ sperm/mL by using Gent extender containing no supplements (control) and the following supplements with three different concentrations: α-tocopherol (0.5, 1, and 2 mM) and ascorbic acid (0.45, 0.9, and 1.8 g/L). After thawing, all samples were maintained at 37°C, while analyses were performed at 0, 60, and 120 minutes. Evaluation of viability and acrosome status (using Pisum sativum agglutinin conjugated to fluorescein isothiocyanate and propidium iodide), mitochondrial membrane potential (5,5′,6,6′-tetrachloro-1,1′,3,3′tetraethylbenzimidazolyl carbocyanine iodine [JC-1]), membrane lipid peroxidation (LPO; C₁₁-BODIPY^581/591), and stability of the plasmatic membrane (merocyanine 540 and Yo-Pro-1) of each sample was determined by flow cytometry. Relative to the control group, supplementation with α-tocopherol improved (P ≤ .05) postthaw membrane LPO, yet the higher concentrations of ascorbic acid (0.9 and 1.8 g/L, respectively) showed a negative effect on membrane LPO. Neither antioxidant significantly increased (P > .05) the acrosome integrity and mitochondrial membrane potential of frozen-thawed spermatozoa, although supplementation with α-tocopherol and ascorbic acid (0.9 and 1.8 g/L, respectively) had a positive effect on membrane integrity and stability (P ≤ .05). For all semen parameters, the lower concentration of ascorbic acid (0.45 g/L) did not show significant differences (P > .05) compared with the control. In conclusion, α-tocopherol seems to be an efficient antioxidant for reducing the oxidative stress provoked by cryopreservation, decreasing lipid peroxidation on equine spermatozoa.     

Morphology,accumulation and survival of Desmanthus under different planting densities and harvest heights

The use of legumes is an important strategy for animal feeding, especially during the dry season. The aim was to evaluate the effect of planting densities (40,000; 15,625 and 10,000 plants ha⁻¹) and harvest heights (20 and 40 cm) on the morphology, accumulation and survival of Desmanthus (Desmanthus pernambucanus [L.] Thellung), cultivated in subhumid tropical region, as well as to estimate the repeatability of the evaluated characteristics and the optimal number of measurements. The treatments were randomized in blocks, with subdivided plots and four replicates. Planting densities were evaluated in the plots and the harvest heights in the subplots. Eight harvests were carried out with an interval of 84 days. Morphological and productive characteristics and survival were evaluated. Cultivation under density of 40,000 plants ha⁻¹ produced taller plants, with higher leaf area index (LAI = 0.98), light interception (LI = 49%), individual accumulations (18.8 g DM plant⁻¹) and by area (576.5 kg DM ha⁻¹ harvest⁻¹), although resulting in reduced plant stand (66%). Harvest heights do not affect accumulation and survival. It is possible to reduce the number of measurements for stem diameter, number of leaflets per leaf (R² = 95%), plant height, canopy diameter, LAI, LI, leaf length and width, number of leaves per branch, branch diameter and LBR (R² = 90%), optimizing resources for future research. Desmanthus has potential for use in protein banks, being harvested in the rainy season, conserved and supplied in addition to animals, but plant growth is minimal during the dry season under rainfed conditions.     

Genotypic characterization of Toxoplasma gondii in sheep from Brazilian slaughterhouses: new atypical genotypes and the clonal type II strain identified

Toxoplasma gondii strains are genetically diverse in South America. To date, hundreds of T. gondii isolates from different animal hosts were genotyped in Brazil, most of them are different from those identified around the world. This study aimed to determine T. gondii infection rate in sheep from Brazilian slaughterhouses, as well as the genotype of these isolates. T. gondii antibodies were detected in 66/602 (10.96%) serum samples through modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT). MAT-HS and IFAT-IgG presented high concordance (0.95) and strong correlation (r=0.79). T. gondii DNA was detected in tissue samples of 33% (22/66) serum positive sheep by PCR of the 529 bp repetitive element. In the bioassay in mice, T. gondii were detected in mice brain or muscle tissues in 30% (20/66) of serum positive sheep. Positive samples were typed through Restriction Fragment Length Polymorphism (RFLP-PCR) using 11 markers: SAG1, SAG2 (5'-3'SAG2 and alt.SAG2), SAG3, BTUB, GRA6, L358, c22-8, c29-6, PK1, Apico and CS3. Of 22 samples, 13 were positive and 9 genotypes were identified. Four of these 9 genotypes are unique. Nine samples had negative results in RFLP-PCR typing, which may be due to low DNA concentration. Six isolates were virulent killing mice between 12 and 25 days postinfection. Two non-virulent isolates belonged to clonal type II genotype, which were not observed in Brazil previously. These findings confirm the high diversity and high frequency of virulent genotypes among Brazilian animals. This study also proved the presence of type II T. gondii in Brazil.