Physiological Studies on Postharvest Leaf Blackening in Cut Flower Protea Species.

To develop an understanding of the physiology which results in postharvest leaf blackening, cut flower Protea species were studied in relation to changes in leaf carbohydrate metabolism, membrane deterioration, and oxidative enzyme activity. Rapid development of leaf blackening in the dark was correlated with low starch and sucrose concentrations. Postharvest decline in leaf carbohydrate status appears to be associated with inflorescence sink demand. Leaf blackening was reduced in the light and carbohydrate pools were maintained due to photosynthesis. In floral stems of P. neriifolia, P. Susannae x compacta and P. eximia (which have differing susceptibilities to leaf blackening), leaf blackening was highest in P. eximia and lowest in P. Susannae x compacta. Preharvest sucrose concentrations were inversely related to leaf blackening, however preharvest starch concentrations were not related to leaf blackening. Low daytime photosynthetic rates and stomatal closure suggest some Protea species may be CAM plants. Leaf blackening may be related more to inflorescence sink demand after harvest than preharvest carbohydrate reserves. In P. neriifolia, postharvest addition of 0.5% exogenous sugar or decapitation of the flowerhead did not delay leaf blackening. A 24-h 20% sucrose pulse reduced blackening to that of vegetative stems. Starch concentrations dropped ca. 70% within 24-h of harvest. Leaves with reduced leaf blackening maintained higher levels of starch and sucrose early in the postharvest period. Low levels of lipid peroxidation and oxidized glutathione concentrations indicated that membrane damage (reduced leaf antioxidant status) did not precede appearance of blackening symptoms. Polyphenol oxidase (PPO) and peroxidase (POD) activities in leaves of P. Susannae x compacta indicated that PPO activity in dark-held stems may not be related to leaf blackening. POD and phenolic concentrations related more closely with appearance of leaf blackening. Chlorophyll and protein concentrations suggested that blackening is not related to senescence, but may result from a wounding response

Inclusive School Community: Why is it so Complex?

This paper addresses the question: why is it so hard for school communities to respond to diversity in learners, staff and parents in inclusive ways? The authors draw on theory and recent professional experience in Queensland, Australia, to offer four guiding principles that address traditional assumptions about learning that result in inequality of opportunity and outcomes for students. The authors suggest these principles to support the development of a more inclusive school community: (1) develop a learning community incorporating a critical friend; (2) value and collaborate with parents and the broader community; (3) engage students as citizens in school review and develop¬ment; and (4) support teachers’ critical engagement with inclusive ideals and practices. The authors describe how the principles can work in concert in a school community

Strategies for eliminating chicken manure odour in horticultural applications

Application of chicken manure is commonly practiced in the horticultural industry due to its value as a fertiliser, ability to improve soil properties and relatively low cost. An unpleasant odour is inherently associated with poultry manure and is considered one of the major limitations in applying chicken manure to production land. Odours originating from chicken manure result from a combination of up to 150 compounds including volatile fatty acids, mercaptans, esters, carbonyls, aldehydes, alcohols, ammonia and amines. Odours are mainly generated by decomposition of chicken faeces, feathers, spilled feed, dust and bedding materials. Issues related to odour from chicken manure are associated with three main locations: sites of production and land application and storage areas. Many strategies have been tested for odour management at production sites, however, odour control, associated with storage and land application, are yet to be addressed. Since odour management is one of the major elements of overall environment management in crop production, this review provides an assessment of odour issues associated with use of chicken manure in the horticultural industry with special reference to minimising odour at storage and land application sites

Polydiacetylene-based sensors to detect food spoilage at low temperatures

Colorimetric gas sensors that detect early release of gases from food spoilage are of great importance in food safety and food conservation. Yet, such sensors are not broadly implemented as they are incompatible with food packaging and non-functional at the low temperatures at which food is stored. Here we report a low cost, highly sensitive ammonia sensor that can be easily incorporated into food packaging to monitor food spoilage at temperatures ranging between −20 °C and room temperature. To fabricate the film sensors, we polymerized self-assembled polydiacetylene vesicles stabilized with cellulose nanocrystals in chitosan matrix. By optimizing this fabrication process, we were able to increase the local concentration of polydiacetylene vesicles at the surface of the film, thus enhancing the operational temperature, response time, and sensitivity to ammonia. The polydiacetylene-based film sensors exhibited a distinctive blue-to-red colorimetric response after being exposed to spoiled meat, even at sub-zero temperatures

Consumer evaluation of ‘Veggycation®’ : a website promoting the health benefits of vegetables

Issue addressed: Whether the website Veggycation® appeals to particular groups of consumers significantly more than other groups. Methods: Australian adults aged _18 years (n = 1000) completed an online survey. The website evaluation instrument used was tested for validity and reliability. Associations between demographic variables and website evaluation dimensions of attractiveness, content, user-friendliness and loyalty intentions were examined using a general linear model (GLM). The appraisal of the website was further investigated based on the respondents’ daily consumption level of vegetables and the importance they attach to vegetable consumption in their diet, using GLM and a Tukey’s all-pair comparison. Results: Veggycation® has a high level of acceptance among the Australian community with certain groups evaluating the website more favourably. These include women, people aged_29 years, higher income respondents, non-metro respondents and those who viewed vegetables as extremely important in their daily diet. Conclusions: Customisation of the website for consumer groups with low vegetable consumption is recommended. Designing tailored communication tools will assist in enhancing the knowledge base of vegetable-related health benefits and may promote vegetable consumption among the Australian population