richmond Narh | Rheinische Friedrich-Wilhelms-Universität Bonn (original) (raw)
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Papers by richmond Narh
Plant and Soil, 2016
Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim... more Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim of this study was to differentiate between responses to acute Fe stress during the vegetative stage and chronic Fe stress throughout the growing period. Methods Six rice genotypes were tested in a semiartificial greenhouse setup, in which acute (almost 1500 mg L −1 Fe in soil solution during the vegetative stage) and chronic (200 to 300 mg L −1 Fe throughout the season) Fe toxicity were simulated. Results Acute Fe stress induced early development of heavy leaf bronzing, whereas moderate symptoms occurred in the chronic treatment throughout the season. Grain yields were only reduced in the chronic stress treatment (−23 %) due to reductions in spikelet fertility, grain number and grain weight. Symptom formation during the early growth stages did not reflect yield responses in all genotypes. Only one genotype showed increases in grain Fe concentrations (24 % in the acute stress and 44 % in the chronic stress) compared to the control. Conclusions Contrasting genotypes responded differently to acute and chronic Fe toxicity, and one genotype showed consistent tolerance and the ability to translocate excess Fe into grains. These traits can be useful in the adaptive breeding of rice for Fe toxic environments.
Journal of Soil Science and Environmental Management, Dec 31, 2015
Frei et al , 2016
Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim... more Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim of this study was to differentiate between responses to acute Fe stress during the vegetative stage and chronic Fe stress throughout the growing period. Methods Six rice genotypes were tested in a semiartificial greenhouse setup, in which acute (almost 1500 mg L −1 Fe in soil solution during the vegetative stage) and chronic (200 to 300 mg L −1 Fe throughout the season) Fe toxicity were simulated. Results Acute Fe stress induced early development of heavy leaf bronzing, whereas moderate symptoms occurred in the chronic treatment throughout the season. Grain yields were only reduced in the chronic stress treatment (−23 %) due to reductions in spikelet fertility, grain number and grain weight. Symptom formation during the early growth stages did not reflect yield responses in all genotypes. Only one genotype showed increases in grain Fe concentrations (24 % in the acute stress and 44 % in the chronic stress) compared to the control. Conclusions Contrasting genotypes responded differently to acute and chronic Fe toxicity, and one genotype showed consistent tolerance and the ability to translocate excess Fe into grains. These traits can be useful in the adaptive breeding of rice for Fe toxic environments.
Chemical soil degradation after erosion is the second most abundant form of soil degradation and ... more Chemical soil degradation after erosion is the second most abundant form of soil degradation and as
such poses a threat to our finite soil resource, as it tends to render it less usable. It is therefore
necessary to understand the means by which soils are degraded chemically. This review paper seeks to
highlight some of the causes of soil chemical degradation. One way by which soils degrade chemically
is through soil contamination; either by diffuse contamination or from localised sources. Drivers such
as salinization, acidification of soils, chemical fertilizer application and use of pesticides all tend to aid
the process of soil chemical degradation. The review paper sheds light on these drivers of degradation
and also discusses some assessment methods developed to determine soil chemical degradation. In
assessing chemical degradation, a combination of assessment tools and soil quality indicator
parameters or single assessment tools may be employed. Some of these tools include ecotoxicological
approach, soil quality test. A combination of two or more assessment tools aids in the process of
restoration of the soil. Chemically degraded soils may be irreversible in most cases and as such its
prevention will aid in agricultural sustainability.
Plant and Soil, 2016
Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim... more Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim of this study was to differentiate between responses to acute Fe stress during the vegetative stage and chronic Fe stress throughout the growing period. Methods Six rice genotypes were tested in a semiartificial greenhouse setup, in which acute (almost 1500 mg L −1 Fe in soil solution during the vegetative stage) and chronic (200 to 300 mg L −1 Fe throughout the season) Fe toxicity were simulated. Results Acute Fe stress induced early development of heavy leaf bronzing, whereas moderate symptoms occurred in the chronic treatment throughout the season. Grain yields were only reduced in the chronic stress treatment (−23 %) due to reductions in spikelet fertility, grain number and grain weight. Symptom formation during the early growth stages did not reflect yield responses in all genotypes. Only one genotype showed increases in grain Fe concentrations (24 % in the acute stress and 44 % in the chronic stress) compared to the control. Conclusions Contrasting genotypes responded differently to acute and chronic Fe toxicity, and one genotype showed consistent tolerance and the ability to translocate excess Fe into grains. These traits can be useful in the adaptive breeding of rice for Fe toxic environments.
Journal of Soil Science and Environmental Management, Dec 31, 2015
Frei et al , 2016
Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim... more Background and aims Iron (Fe) toxicity is a widespread stress in lowland rice production. The aim of this study was to differentiate between responses to acute Fe stress during the vegetative stage and chronic Fe stress throughout the growing period. Methods Six rice genotypes were tested in a semiartificial greenhouse setup, in which acute (almost 1500 mg L −1 Fe in soil solution during the vegetative stage) and chronic (200 to 300 mg L −1 Fe throughout the season) Fe toxicity were simulated. Results Acute Fe stress induced early development of heavy leaf bronzing, whereas moderate symptoms occurred in the chronic treatment throughout the season. Grain yields were only reduced in the chronic stress treatment (−23 %) due to reductions in spikelet fertility, grain number and grain weight. Symptom formation during the early growth stages did not reflect yield responses in all genotypes. Only one genotype showed increases in grain Fe concentrations (24 % in the acute stress and 44 % in the chronic stress) compared to the control. Conclusions Contrasting genotypes responded differently to acute and chronic Fe toxicity, and one genotype showed consistent tolerance and the ability to translocate excess Fe into grains. These traits can be useful in the adaptive breeding of rice for Fe toxic environments.
Chemical soil degradation after erosion is the second most abundant form of soil degradation and ... more Chemical soil degradation after erosion is the second most abundant form of soil degradation and as
such poses a threat to our finite soil resource, as it tends to render it less usable. It is therefore
necessary to understand the means by which soils are degraded chemically. This review paper seeks to
highlight some of the causes of soil chemical degradation. One way by which soils degrade chemically
is through soil contamination; either by diffuse contamination or from localised sources. Drivers such
as salinization, acidification of soils, chemical fertilizer application and use of pesticides all tend to aid
the process of soil chemical degradation. The review paper sheds light on these drivers of degradation
and also discusses some assessment methods developed to determine soil chemical degradation. In
assessing chemical degradation, a combination of assessment tools and soil quality indicator
parameters or single assessment tools may be employed. Some of these tools include ecotoxicological
approach, soil quality test. A combination of two or more assessment tools aids in the process of
restoration of the soil. Chemically degraded soils may be irreversible in most cases and as such its
prevention will aid in agricultural sustainability.