Soil organic carbon in cropping sequences with predominance of soya bean in the argentinean humid Pampas

Soya bean (Glycine max (L.) Merr.) monoculture can lead to a decrease in labile fractions of soil organic carbon (SOC). This study sought to evaluate the effects of cover crops (CC), application of fertilizer, and crop rotation on SOC, particulate organic carbon (POC), and soil carbon input in soya bean-based crop sequences under a no-till cropping system in the Argentinean Humid Pampas. Five crop sequences at two sites differing in initial SOC were evaluated: continuous soya bean (Sb), continuous soya bean fertilized with phosphorus (P) and sulphur (S) (Sbf), grass CC / PS-fertilized soya bean (CC/Sbf), nitrogen (N)-fertilized CC / PS-fertilized soya bean (CCf/Sbf) and NPS-fertilized crop rotation with high intensification sequence index (ISI) (Rot). At 0–5 cm, SOC and POC were higher (p < .05) in the sequences with higher residue-C supply (CC/Sbf; CCf/Sbf and Rot) at both sites. Changes in SOC at 0–20 cm simulated by AMG model closely tracked measured results at 0–20 cm. Findings from this study suggest that the inclusion of CC or crop rotation with high ISI improved C balance in soils under crop sequences with soya bean predominance.     

PREPUBIC AND TRANSRECTAL ULTRASONOGRAPHY OF THE CANINE PROSTATE: A COMPARATIVE STUDY

A comparative study was conducted in ten dogs with signs of prostatic disease in order to evaluate the usefulness of the prepubic and transrectal ultrasonography for the examination of the prostate gland and for prostate biopsy guidance. Both techniques were adequate to identify the prostate gland and prostatic urethra. Transrectal ultrasound found 5 occurrencies of parenchymal echogenicity changes whereas the prepubic technique found only 2. Lesions in the cranial prostatic margin (two dogs) were detected only by prepubic ultrasound. Lesions of the caudal prostatic margin (six dogs), prostatic urethra disruption (two dogs) and prostatic capsule abnormalities (five dogs) were only recognized by the transrectal approach. Prepubic ultrasonography was useful for biopsy guidance of cranial prostatic lesions and transrectal ultrasonography was a good means for biopsy guidance of caudal lesions.     

Computed tomography is a feasible method for quantifying bone density in Macaca mulatta

Osteopathologies are a result of advanced age and decreased bone density and represent a global health problem. It is therefore important to generate models for longitudinal studies of the pathophysiology in order to improve early diagnosis and develop preventive therapies. For this kind of research, the use of computed tomography (CT) to evaluate bone health offers advantages over other techniques since it provides more complete information. The aim of this prospective, pilot study was to obtain measurements of the left femur from a population in captivity of 32 rhesus monkeys (Macaca mulatta) in order to standardize the model for future research. Healthy subjects from 5 to 28 years old were chosen. Three groups with different ages were formed as follows: (1) 5–9 years, (2) 10–19 years, and (3) 20–28 years. Semi‐automatic segmentation by threshold defined the regions of interest, which were subdivided in the range of 300–700 Hounsfield units (HU) for trabecular bone and >700 HU for cortical bone. Then, the proportional ratios of the volumes of trabecular bone and cortical bone were obtained. Significant differences (analysis of variance test) in the averages of Hounsfield units, cortical, and trabecular bone proportions from each age group proved that a decrease in bone density begins at approximately 20 years of age. The values presented here, as well as the method to obtain them from CT scans, can be used as a baseline in a primate model for long‐term research in bone pathology diagnosis and treatment.     

Cytoplasmic and nuclear genetic components of membrane stability of winter wheat plants exposed to sub‐zero temperatures

Winter wheat (Triticum aestivum L.) is seeded in the autumn and harvested the following summer, and therefore, must survive multiple episodes of subfreezing temperatures throughout the winter months. Cellular membrane stability following exposure to subfreezing temperatures contributes to the ability to survive these episodes. This study investigated the inheritance of the ability to tolerate subfreezing temperatures with a seven‐parent diallel cross analysis of cellular membrane integrity as measured by electrolyte leakage after exposure to ?10 or ?14 °C. Significant differences in membrane stability were found among the parent lines. The inheritance of the freezing tolerance as measured by electrolyte leakage was complex and characterized by significant additive, dominant and cytoplasmic effects. General combining ability, indicative of additive genetic effects, were significant at both test temperatures, but accounted for 25.5% of the variance at the ?10° C test temperature, and only 4% of the variance at the ?14 °C test temperature. Specific combining ability, indicative of genetic dominance effects, were significant at both test temperatures, but accounted for only 14.6% of the variance at the ?10 °C test temperature, and 38% of the variance at the ?14 °C test temperature. Reciprocal (cytoplasmic) effects were significant and accounted for about 20% of the variance at both test temperatures. Cytoplasmic effects contributing to greater membrane stability were especially apparent in the cultivar Tiber when crossed to Masami, Lewjain, or Hatton. These results suggest that efforts to improve freezing tolerance are complicated by differing gene action at different test temperatures and also may benefit from identifying specific combinations of nuclear and cytoplasm sources that are most conducive to membrane stability following freezing.     

Evidence that subsistence farmers have domesticated indigenous fruits (Dacryodes edulis and Irvingia gabonensis) in Cameroon and Nigeria

Ten fruit and kernel traits were measured in 152 Irvingia gabonensis and 293 Dacryodes edulis trees from 6 villages in Cameroon and Nigeria. Frequency distribution curves were used to examine the range of variation of each trait of each species in each village and aggregated into national and regional populations. There were differences between the village sub-populations, with regard to the normality (e.g., mean kernel mass of D. edulis) or skewness (e.g., mean flesh depth of D. edulis) of the distribution curves and in the degree of separation between the individual village populations along the x axis, resulting in the development of a bimodal distribution in the regional population. For all traits, populations of both species differed significantly between countries, but only in D. edulis were there significant differences between the Cameroon populations. On the basis of the results of this study, D. edulis can be said to be virtually wild in Nigeria but semi-domesticated in Cameroon, while I. gabonensis is wild in Cameroon and semi-domesticated in Nigeria. These results are discussed with regard to a hypothesis that the range and frequency of variation in the different populations can be used to identify five stages of domestication. From a comparison of the frequency distribution curves of desirable versus undesirable traits, and statistically identifyable changes in skewness and kurtosis, it is concluded that as a result of the farmers’ own efforts by truncated selection, D. edulis is between Stages 2 and 3 of domestication (with a 67% relative gain in flesh depth) in Cameroon, while I. gabonensis in Nigeria is at Stage 2 (with a 44% relative gain in flesh depth). In this study, genetic diversity seems to have been increased, and not reduced, by domestication. This revised version was published online in June 2006 with corrections to the Cover Date.     

Pigments in avocado tissue and oil

Pigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined carotenoid and chlorophyll pigment concentrations in the skin and three sections of the flesh (outer dark green, middle pale green, and inner yellow flesh-nearest the seed) and anthocyanin concentrations in the skin of Hass avocado during ripening at 20 degrees C. Pigments were extracted from frozen tissue with acetone and measured using high-performance liquid chromatography. Pigments were also measured in the oil extracted from freeze-dried tissue sections by an accelerated solvent extraction system using hexane. Carotenoids and chlorophylls identified in the skin, flesh, and oil were lutein, alpha-carotene, beta-carotene, neoxanthin, violaxanthin, zeaxanthin, antheraxanthin, chlorophylls a and b, and pheophytins a and b with the highest concentrations of all pigments in the skin. Chlorophyllides a and b were identified in the skin and flesh tissues only. As the fruit ripened and softened, the skin changed from green to purple/black, corresponding to changes in skin hue angle, and a concomitant increase in cyanidin 3-O-glucoside and the loss of chlorophyllide a. In flesh tissue, chroma and lightness values decreased with ripening, with no changes in hue angle. The levels of carotenoids and chlorophylls did not change significantly during ripening. As fruit ripened, the total chlorophyll level in the oil from the flesh sections remained constant but declined in the oil extracted from the skin.     

Environmental conditions encountered during typical consumer retail display affect fruit and vegetable quality and waste

Temperature and relative humidity (RH) are the most important environmental factors affecting the sensory quality of fresh produce, and therefore, the consumer acceptability for fruits and vegetables displayed in a produce department. Poor temperature management inevitably occurs in commercial handling and reduces the quality and maximum potential shelf life of fruits and vegetables. Since there is a lack of information on the actual temperatures registered inside local distribution trucks or in consumer retail displays, and the effects on the produce quality, the current study was designed to evaluate the segment of the distribution chain that comprises the time the produce arrives from the distribution center to the store, is displayed at the store, and then stored under household conditions. Temperature and RH were recorded in three different produce departments, at reception and during a 6-week retail display period. Truck and produce temperatures were collected immediately upon opening of the doors, and display temperatures were monitored inside 27 refrigerated and non-refrigerated retail displays. Visual quality of 37 different produce items was evaluated, and surface or pulp temperatures were measured immediately upon unloading from the delivery truck. Reasons for produce waste were recorded on a daily basis during a 6-week period. Shelf life studies were conducted under simulated household conditions using samples collected at the stores. Results from this study showed that chilling-sensitive commodities were transported under too cold conditions, whereas heat-sensitive commodities were transported under too warm conditions. Visual quality of the produce received at the store ranged from good to poor depending on the fruit or vegetable evaluated, with raspberry receiving the lowest visual quality score in 6.7% of store deliveries, and banana, fresh-cut vegetables, peach and pineapple receiving the best visual quality score in 100% of store deliveries. Temperatures measured inside retail displays showed a wide variation, depending on the store and location inside the display, ranging from ?1.2 °C to 19.2 °C in refrigerated displays and from 7.6 °C to 27.7 °C in non-refrigerated displays. RH ranged from 55.9% to 92.9% in refrigerated displays and from 29.7% to 86.6% in non-refrigerated displays. Poor temperature management was the major cause of produce waste (55%) whereas expired date and mechanical damage accounted for 45% of the produce wasted. Results from this study show that fruits and vegetables are often handled under adverse environmental conditions, resulting in produce with poor quality and shorter shelf life, and increased waste at the retail and consumer levels.