Overview
Background
Acid soil, Aluminium toxicity, soil acidity, rhizosphere, plant roots, root growth, plant cell wall, nutrient uptake, plant nutrition
Having completed my B.Sc. majoring in Biochemistry, Microbiology and Chemistry, I completed my M.Sc. (Agric) in Horticultural Science. After completing a PhD on the effect of heavy metals and aluminium on plant root biochemistry, I have worked for various plant biotechnology companies, focussing on genetic engineering of crops, in-vitro growth, propagation systems and salinity tolerant tree crops. After rejoining the University, I have been involved in minesite rehabilitation, focussing on plant-soil-water relationships. I have completed and ARC funded research on Al toxicity, focussing on the hydrolysis of Al in plant roots. I am currently researching the effect of coal seam water application and the movement of salts in soils. I am also teaching the introductory Soil Science course to undergraduate students.
Availability
- Dr Bernhard Wehr is:
- Available for supervision
Fields of research
Research interests
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Plant-soil interactions
Plant roots are growing in soil and plants obtain most of their water and nutrients from the soil. Hostile soil conditions can significantly lower yields and affect profitability of producers. Common soil constraints in Australia and soil salinity and alkalinity, and poor soil physical properties. Management of soil constaints is necessary to increase yield and maintain profitability.
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Plant root physiology and plant cell walls
Plant cell walls are the part of plants roots in intimate contact with the soil. In particular, the anionic and cations charges found in plant cell walls play an important in how the plant perceives the soil environment and this affects uptake of nutrients by plant roots. Furthermore, the architecture of the root system affects how plants can exploit the soil for maximise uptake of water and nutrients.
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Aluminium toxicity and tolerance in plants
Aluminium toxicity is a significant problem in Australia and the rest of the world. In acid soils, dissolution of Al minerals releases trivalent Al ions which impair root growth. Consequently, water and nutrient uptake is decreased, resulting in yield losses. Understanding why Al is toxic to plant roots and management of acid soils to overcome Al toxicity is important to maintain or increase productivity.
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Agroforestry
Diversification of agricultural land use use to incorporate forestry can have a number of benefit for the environment and the producer. By setting aside less productive land for forestry, land degradation can be reversed or at least minimised by reducing wind and water erosion. In addition, forestry can provide habitat for native species and increase biodiversity. Beneficial effects are lowering of watertables in areas where dryland salinity is an issue, thereby preventing land degradation, increased soil carbon sequestration, increased visual amenity and an additional income stream.
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Land-disposal of waste products
Beneficial re-use of waste water and waste products such a manure and sewage can maintain or improve productivity by supplying water and nutrients to crops. Careful analysis of risks and benefits is required to evaluate the suitability of land disposal of waste products.
Works
Search Professor Bernhard Wehr’s works on UQ eSpace
2008
Conference Publication
Determination of charge density of colloids by dye binding and can it be applied to plant cell walls?
Wehr, J. B., Blamey, F. P. C., Kerven, G. L., Horst, W. J., Hanna, J. V. and Menzies, N. W. NW (2008). Determination of charge density of colloids by dye binding and can it be applied to plant cell walls?. Joint Conference of the Australia and New Zealand Societies of Soil Science, Palmerston North, New Zealand, 1-5 December 2008. Palmerston North, New Zealand: Massey University.
2008
Conference Publication
Using Gluconacetobacter xylinus as a tool to investigate aluminium interactions with plant cell walls
McKenna, B. A., Wehr, J. B. and Menzies, N. W. (2008). Using Gluconacetobacter xylinus as a tool to investigate aluminium interactions with plant cell walls. Joint Conference of the Australia and New Zealand Societies of Soil Science: ‘SOIL – the living skin of Planet Earth’, Palmerston North, New Zealand, 1-5 December 2008. Palmerston North, New Zealand: Massey University.
2007
Other Outputs
Aluminum
Wehr, J. B., Blamey, F. P. C. and Menzies, Neal (2007). Aluminum.
2006
Journal Article
Revegetation strategies for bauxite refinery residue: A case study of Alcan Gove in Northern Territory, Australia
Wehr, J. B., Fulton, I. and Menzies, N. W. (2006). Revegetation strategies for bauxite refinery residue: A case study of Alcan Gove in Northern Territory, Australia. Environmental Management, 37 (3), 297-306. doi: 10.1007/s00267-004-0385-2
2006
Conference Publication
Chemical speciation of aluminium bound to pectin as model for aluminium binding in the plant cell wall
Wehr, Bernhard, Blamey, Pax, Kerven, Graham, Horst, Walter, Hanna, John and Menzies, Neal (2006). Chemical speciation of aluminium bound to pectin as model for aluminium binding in the plant cell wall. ASSSI-ASPAC-ACMS National Soils Conference, Adelaide, South Australia, Australia, 3-7 December 2006.
2005
Journal Article
Hydraulic properties of layered soils influence survival of Rhodes grass (Chloris gayana Kunth.) during water stress
Wehr, J. B., So, H. B., Menzies, N. W. and Fulton, I. (2005). Hydraulic properties of layered soils influence survival of Rhodes grass (Chloris gayana Kunth.) during water stress. Plant and Soil, 270 (1), 287-297. doi: 10.1007/s11104-004-1651-z
2004
Journal Article
Inhibition of cell-wall autolysis and pectin degradation by cations
Wehr, J. B., Menzies, N. W. and Blamey, F. P. C. (2004). Inhibition of cell-wall autolysis and pectin degradation by cations. Plant Physiology And Biochemistry, 42 (6), 485-492. doi: 10.1016/j.plaphy.2004.05.006
2004
Journal Article
Alkali hydroxide-induced gelation of pectin
Wehr, J. B., Menzies, N. W. and Blamey, F. P. C. (2004). Alkali hydroxide-induced gelation of pectin. Food Hydrocolloids, 18 (3), 375-378. doi: 10.1016/S0268-005X(03)00124-3
2003
Journal Article
Model studies on the role of citrate, malate and pectin esterification on the enzymatic degradation of Al- and Ca-pectate gels: possible implications for Al-tolerance
Wehr, J. B., Menzies, N. W. and Blamey, F. P. C. (2003). Model studies on the role of citrate, malate and pectin esterification on the enzymatic degradation of Al- and Ca-pectate gels: possible implications for Al-tolerance. Plant Physiology and Biochemistry, 41 (11-12), 1007-1010. doi: 10.1016/j.plaphy.2003.06.001
1998
Other Outputs
Reactions of cations with pectin and root cell walls
Wehr, Johannes Bernhard (1998). Reactions of cations with pectin and root cell walls. PhD Thesis, School of Land, Crop and Food Sciences, The University of Queensland. doi: 10.14264/365874
1995
Journal Article
Agmatine determination in plant material: Aspects of the benzoylation and high performance liquid chromatographic analysis
Wehr, J. B. (1995). Agmatine determination in plant material: Aspects of the benzoylation and high performance liquid chromatographic analysis. Phytochemical Analysis, 6 (5), 244-250. doi: 10.1002/pca.2800060504
Funding
Supervision
Availability
- Dr Bernhard Wehr is:
- Available for supervision
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Available projects
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Effect of silicon on plant physiological processes
This is a short-term project suited for an Hons/Masters level study.
Current field trials are conducted in which different types silicon amendments have been added to soil. The silicon has effects on both soil properties and plant physioloigcal processes. This project will only investigate plant responses, e.g. water stress tolerance, disease resistance, silicon uptake and distribution in crop species.
The project is suited to a student with good plant science background. The project can be located at either Gatton or St Lucia
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Effect of silicon on soil properties
This is a short-term project suited for an Hons/Masters level study.
Current field trials are conducted in which different types silicon amendments have been added to soil. The silicon has effects on both soil properties and plant physioloigcal processes. This project will only investigate changes in soil properties, e.g. water holding capacity, aggregation and aggregate strength, nutrient availability (esp phosphorus), and soil organic matter turnover.
The project is suited to a student with good soil science/chemistry background. The project can be located at either Gatton or St Lucia.
Supervision history
Current supervision
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Doctor Philosophy
Ameliorating soil constraints using inorganic and organic amendments under rainfed conditions
Associate Advisor
Other advisors: Adjunct Professor Ram Dalal AM, Dr Yash Dang
Completed supervision
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2023
Doctor Philosophy
The amelioration of sodic soils with gypsum and organic amendments
Principal Advisor
Other advisors: Professor Peter Kopittke, Adjunct Professor Ram Dalal AM
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2023
Doctor Philosophy
Evaluation of environmental, genotypic and nutritional factors influencing yield and quality of garlic
Principal Advisor
Other advisors: Dr Stephen Harper
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2020
Doctor Philosophy
The impact of banding urea and enhanced efficiency fertilizers on nitrogen transformations and the implications for nitrogen use efficiency in high-risk environments
Associate Advisor
Other advisors: Professor Michael Bell
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2010
Doctor Philosophy
Effects of toxic cations on bacterial cellulose pectin composites used as cell wall analogs
Associate Advisor
Media
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