Responses in carcass lean pH at 24 hours post-mortem in lines of Large White pigs selected for growth rate on a fixed ration over a set time

A restricted maximum likelihood analysis applied to an animal model showed no significant differences (P > 0.05) in pH value of the longissimus dorsi measured at 24 h post-mortem (pH24) between high and low lines of Large White pigs selected over 4 years for post-weaning growth rate on restricted feeding. Genetic and phenotypic correlations between pH24 and production and carcass traits were estimated using all performance testing records combined with the pH24 measurements (5.05-7.02) on slaughtered animals. The estimate of heritability for pH24 was moderate (0.29 ± 0.18). Genetic correlations between pH24 and production or carcass composition traits, except for ultrasonic backfat (UBF), were not significantly different from zero. UBF had a moderate, positive genetic correlation with pH24 (0.24 ± 0.33). These estimates of genetic correlations affirmed that selection for increased growth rate on restricted feeding is likely to result in limited changes in pH24 and pork quality since the selection does not put a high emphasis on reduced fatness.

Wet-dry cycling extends seed persistence by re-instating antioxidant capacity

Seeds in the field experience wet-dry cycling that is akin to the well-studied commercial process of seed priming in which seeds are hydrated and then re-dried to standardise their germination characteristics. To investigate whether the persistence (defined as in situ longevity) and antioxidant capacity of seeds are influenced by wet-dry cycling, seeds of the global agronomic weed Avena sterilis ssp. ludoviciana were subjected to (1) controlled ageing at 60% relative humidity and 53.5°C for 31 days, (2) controlled ageing then priming, or (3) ageing in the field in three soils for 21 months. Changes in seed viability (total germination), mean germination time, seedling vigour (mean seedling length), and the concentrations of the glutathione (GSH) / glutathione disulphide (GSSG) redox couple were recorded over time. As controlled-aged seeds lost viability, GSH levels declined and the relative proportion of GSSG contributing to total glutathione increased, indicative of a failing antioxidant capacity. Subjecting seeds that were aged under controlled conditions to a wet-dry cycle (to −1 MPa) prevented viability loss and increased GSH levels. Field-aged seeds that underwent numerous wet-dry cycles due to natural rainfall maintained high viability and high GSH levels. Thus wet-dry cycles in the field may enhance seed longevity and persistence coincident with re-synthesis of protective compounds such as GSH.

Lantana camara L. (Verbenaceae) invasion effects on soil physicochemical properties

Lantana camara is a recognized weed of worldwide significance due to its extensive distribution and its impacts on primary industries and nature conservation. However, quantitative data on the impact of the weed on soil ecosystem properties are scanty, especially in SE Australia, despite the pervasive presence of the weed along its coastal and inland regions. Consequently, mineral soils for physicochemical analyses were collected beneath and away from L. camara infestations in four sites west of Brisbane, SE Australia. These sites (hoop pine plantation, cattle farm, and two eucalyptus forests with occasional grazing and a fire regime, respectively) vary in landscape and land-use types. Significant site effect was more frequently observed than effect due to invasion status. Nonetheless, after controlling for site differences, ~50% of the 23 soil traits examined differed significantly between infested and non-infested soils. Moisture, pH, Ca, total and organic C, and total N (but not exchangeable N in form of NO3-) were significantly elevated, while sodium, chloride, copper, iron, sulfur, and manganese, many of which can be toxic to plant growth if present in excess levels, were present at lower levels in soils supporting L. camara compared to soils lacking the weed. These results indicate that L. camara can improve soil fertility and influence nutrient cycling, making the substratum ideal for its own growth and might explain the ability of the weed to outcompete other species, especially native ones.

Using molasses to control inorganic nitrogen and pH in aquaculture ponds

This article describes research designed to determine the molasses addition rates that can control ammonia and pH in eutrophic aquaculture ponds.

Simultaneous prediction of acidity parameters (pH and titratable acidity) in Kefir using near infrared reflectance spectroscopy.

Acidity in terms of pH and titratable acids influences the texture and flavour of fermented dairy products, such as Kefir. However, the methods for determining pH and titratable acidity (TA) are time consuming. Near infrared (NIR) spectroscopy is a non-destructive method, which simultaneously predicts multiple traits from a single scan and can be used to predict pH and TA. The best pH NIR calibration model was obtained with no spectral pre-treatment applied, whereas smoothing was found to be the best pre-treatment to develop the TA calibration model. Using cross-validation, the prediction results were found acceptable for both pH and TA. With external validation, similar results were found for pH and TA, and both models were found to be acceptable for screening purposes.

Boronia heterophylla vase life is influenced more by ethylene than by bacterial numbers or vase solution pH

Bacterial proliferation in both vase solutions and in cut flower stems has been implicated in reducing the vase life of numerous genera. Boronia heterophylla F. Muell. (Red Boronia) vase life was assessed at two stages of floral maturity for nine vase solution treatments covering a pH range of 2.5-5.7. Vase life for advanced harvest maturity stems ranged from 4.2 d in 10 mM citric acid + 50 mg L-1 chlorine (pH 2.5) to 12.9 d after STS pulsing (pH 5.7). For normal harvest maturity stems, the corresponding range was 5.8-19.0 d, respectively. Vase solutions containing 50 mg L-1 chlorine biocide resulted in decreased longevity. In contrast, pulsing with the ethylene-binding inhibitor, STS, significantly increased vase life. The number of bacteria in the vase solutions after 11 d was determined in stems of advanced maturity. The solution with the greatest number of bacteria, 4.0 x 10(10) cfu mL(-1), was water used after STS pulsing and in which the flowers lasted longest. Vase solution bacteria were enumerated on days 0,3, 6, 9 and 12 of the vase period with stems of normal harvest maturity. There was no relationship between vase life and vase solution bacterial numbers ((R) over bar (2) = 0.000). Moreover, there was a negative relationship between numbers of bacteria in basal 0-5 cm stem segments and vase life. As no correlations were evident between longevity and either the pH or vase solution bacterial numbers, B. heterophylla vase life was evidently limited principally by ethylene action. (C) 2013 Elsevier B.V. All rights reserved.