Matching Items (3)
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Description

Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass

Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass with the result of increased mineral P acquisition. However, although AVP1 over-expression also increased shoot biomass in Arabidopsis, this effect was not observed in tomato under phosphate-sufficient conditions. AVP1DOX tomato plants exhibited increased rootward auxin transport and root acidification compared with control plants. AVP1DOX tomato plants were analysed in detail under limiting P conditions in greenhouse and field trials. AVP1DOX plants produced 25% (P=0.001) more marketable ripened fruit per plant under P-deficient conditions compared with the controls. Further, under low phosphate conditions, AVP1DOX plants displayed increased phosphate transport from leaf (source) to fruit (sink) compared to controls. AVP1DOX plants also showed an 11% increase in transplant survival (P<0.01) in both greenhouse and field trials compared with the control plants. These results suggest that selection of tomato cultivars for increased proton pyrophosphatase gene expression could be useful when selecting for cultivars to be grown on marginal soils.

ContributorsYang, Haibing (Author) / Zhang, Xiao (Author) / Gaxiola, Roberto (Author) / Xu, Guohua (Author) / Peer, Wendy Ann (Author) / Murphy, Angus S. (Author) / College of Liberal Arts and Sciences (Contributor)
Created2014-07-01
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Description
Of the many challenges cities face, congestion and air quality are two interrelated issues that despite technological improvements in vehicle emissions standards and engine efficiency, continue to worsen. Of the strategies attempting to reduce automobile dependency, a popular approach adopted by cities is the concept of transit-oriented development (TOD). The

Of the many challenges cities face, congestion and air quality are two interrelated issues that despite technological improvements in vehicle emissions standards and engine efficiency, continue to worsen. Of the strategies attempting to reduce automobile dependency, a popular approach adopted by cities is the concept of transit-oriented development (TOD). The strategy aims to better integrate land use and transportation planning, and is often characterized by a mix of land uses, high density, and proximity to quality public transit. While practitioners and academics argue the economic and environmental benefits of TOD, there are several examples along the Valley Metro light rail corridor where the strategy appears to be failing to attract people, businesses, and ultimately transit riders. The purpose of this study is to explore how urban infrastructure characteristics, specifically transportation connectivity, urban design, and land use interact to support light rail ridership. The study utilizes a rendition of sustainability’s triple-bottom-line framework, wherein economic, environmental, and social elements are represented as criteria in the transportation, land use, and urban design analysis of six Valley Metro light rail stations. Each element has supporting criteria that are ranked relative to the other stations under analysis, culminating in overall TOD scores for each station. The number of TOD projects and ridership trends are also compared, and in combination with the evaluation of urban infrastructure elements, the results suggest the importance of transportation connectivity, pedestrian-scale infrastructure, a sense of place, and employment centers for TOD stations to yield high ridership. Findings are analyzed through a sustainability lens resulting in the proposal of strategic solutions for improving TOD planning methods.
ContributorsSantiago, Rebecca (Author) / Pijawka, David (Contributor) / Prosser, Paul (Contributor)
Created2017-04-17
Description

Global climate models predict increases in precipitation events in the Phoenix-metropolitan area and with the proposition of more flooding new insights are needed for protecting roadways and the services they provide. Students from engineering, sustainability, and planning worked together in ASU’s Urban Infrastructure Anatomy Spring 2016 course to assess:
   

Global climate models predict increases in precipitation events in the Phoenix-metropolitan area and with the proposition of more flooding new insights are needed for protecting roadways and the services they provide. Students from engineering, sustainability, and planning worked together in ASU’s Urban Infrastructure Anatomy Spring 2016 course to assess:
       1. How historical floods changed roadway designs.
       2. Precipitation forecasts to mid-century.
       3. The vulnerability of roadways to more frequent precipitation.
       4. Adaptation strategies focusing on safe-to-fail thinking.
       5. Strategies for overcoming institutional barriers to enable transitions.
The students designed an EPA Storm Water Management Model for the City of Phoenix and forced it with future precipitation forecasts. Vulnerability indexes were created for infrastructure performance and social outcomes. A multi-criteria decision analysis framework was created to prioritize infrastructure adaptation strategies.