22 resultados para Lawns and turfgrasses, LC subs class under SB403 Flowers and flower culture. Ornamental plants

em University of Queensland eSpace - Australia


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Floral volatiles play a major role in plant-insect communication. We examined the influence of two volatiles, phenylacetaldehyde and a-pinene, on the innate and learnt foraging behaviour of the moth Helicoverpa armigera. In dual-choice wind tunnel tests, adult moths flew upwind towards both volatiles, with a preference for phenylacetaldehyde. When exposure to either of these volatiles was paired with a feeding stimulus (sucrose), all moths preferred the learnt odour in the preference test. This change in preference was not seen when moths were exposed to the odour without a feeding stimulus. The learnt preference for the odour was reduced when moths were left unfed for 24 h before the preference test. We tested whether moths could discriminate between flowers that differed in a single volatile component. Moths were trained to feed on flowers that were odour-enhanced using either phenylacetaldehyde or a-pinene. Choice tests were then carried out in an outdoor flight cage, using flowers enhanced with either volatile. Moths showed a significant preference for the flower type on which they were trained. Moths that were conditioned on flowers that were not odour-enhanced showed no preference for either of the odour-enhanced flower types. The results imply that moths may be discriminating among odour profiles of individual flowers from the same species. We discuss this behaviour within the context of nectar foraging in moths and odour signalling by flowering plants.

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Young people living in rural and regional areas are often reported as being less physically active than are young people living elsewhere. An understanding of this phenomenon will inform policies and strategies to address this finding. One source of valuable information is a qualitative understanding of how social relations and cultural meanings influence young people's opportunities and choices in relation to physical activity as told by young people themselves. The study reported here forms a component of a national project to gain insights into young people's engagement with physical activity and physical culture. Data has been collected for over two years with 15 young people residing in rural areas throughout Queensland, using semi- structured interviews. This paper reports the findings of the research. [Author abstract, ed]

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To characterise the physiology of development and senescence for Grevillea 'Sylvia'. oral organs, respiration, ethylene production and ACC concentrations in harvested flowers and flower parts were measured. The respiration rate of harvested inflorescences decreased over time during senescence. In contrast, both ethylene production and ACC concentration increased. Individual flowers, either detached from cut inflorescences held in vases at 20degreesC or detached from in planta inflorescences at various stages of development, had similar patterns of change in ACC concentration and rates of respiration and ethylene production as whole inflorescences. The correlation between ACC concentration and ethylene production by individual flowers detached from cut inflorescences held in vases was poor (r(2)=0.03). The isolated complete gynoecium (inclusive of the pedicel) produced increasing amounts of ethylene during development. Further sub-division of flower parts and measurement of their ethylene production at various stages of development revealed that the distal part of the gynoecium (inclusive of the stigma) had the highest rate of ethylene production. In turn, anthers had higher rates of ethylene production and also higher ACC concentrations than the proximal part of the gynoecium (inclusive of the ovary). Rates of ethylene production and ACC concentrations for tepal abscission zone tissue and adjacent central tepal zone tissue were similar. ACC concentration in pollen was similar to that in senescing perianth tissue. Overall, respiration, ethylene and ACC content measurements suggest that senescence of G. 'Sylvia' is non-climacteric in character. Nonetheless, the phytohormone ethylene is produced and evidently mediates normal flower development and non-climacteric senescence processes.

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bstract: During the Regional Forest Agreement (RFA) process in south-east Queensland, the conservation status of, and threats to, priority vascular plant taxa in the region was assessed. Characteristics of biology, demography and distribution were used to assess the species' intrinsic risk of extinction. In contrast, the threats to the taxa (their extrinsic risk of extinction) were assessed using a decision-support protocol for setting conservation targets for taxa lacking population viability analyses and habitat modelling data. Disturbance processes known or suspected to be adversely affecting the taxa were evaluated for their intensity, extent and time-scale. Expert opinion was used to provide much of the data and to assess the recommended protection areas. Five categories of intrinsic risk of extinction were recognised for the 105 priority taxa: critically endangered (43 taxa); endangered (29); vulnerable (21); rare (10); and presumed extinct (2). Only 6 of the 103 extant taxa were found to be adequately reserved and the majority were considered inadequately protected to survive the current regimes of threatening processes affecting them. Data were insufficient to calculate a protection target for one extant taxon. Over half of the taxa require all populations to be conserved as well as active management to alleviate threatening processes. The most common threats to particular taxa were competition from weeds or native species, inappropriate fire regimes, agricultural clearing, forestry, grazing by native or feral species, drought, urban development, illegal collection of plants, and altered hydrology. Apart from drought and competition from native species, these disturbances are largely influenced or initiated by human actions. Therefore, as well as increased protection of most of the taxa, active management interventions are necessary to reduce the effects of threatening processes and to enable the persistence of the taxa.

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In Australia indigenous peoples have never had a treaty with the dominant cultures; and their on-going marginalisation is some testimony to this. However, they have not languished entirely in a policy free environment: media is one area where some policy advances have been made; but media policy development has experienced a number of problems. It has tended to be monolithic in a situation demanding multi and complex treatments. And funding, as always, never seems sufficient to meet those multi and complex needs. This paper examines a small remote community on the island of Milingimbi off the northern coast of Arnhem Land in Australia's far north. People in East Arnhem Land refer to themselves collectively as Yolngu. This community is not typical of many documented cases of media relations between indigenous and non-indigenous peoples; however, the fact that it tends to overturn much of the conventional scholarship surrounding indigenous peoples and the media, helps shed new light on the inadequacy of not only monolithic media policy, but the inadequacy of media-only approaches to policy. Arguably, the significance of the media in Milingimbi is part of a 'triangulated' relationship between indigenous and dominant cultures. That triangulation also involves appropriate forms of government and education, which coupled with appropriate media appear to offer new ways of seeing self-government alongside relative cultural and economic autonomy.