Ross M. Welch

Bio: Ross M. Welch is an academic researcher from Cornell University. The author has contributed to research in topics: Bioavailability & Zinc. The author has an hindex of 66, co-authored 167 publications receiving 14233 citations. Previous affiliations of Ross M. Welch include United States Department of Agriculture & Baylor College of Medicine.

Breeding for micronutrients in staple food crops from a human nutrition perspective

Abstract: Over three billion people are currently micronutrient (i.e. micronutrient elements and vitamins) malnourished, resulting in egregious societal costs including learning disabilities among children, increased morbidity and mortality rates, lower worker productivity, and high healthcare costs, all factors diminishing human potential, felicity, and national economic development. Nutritional deficiencies (e.g. iron, zinc, vitamin A) account for almost two-thirds of the childhood death worldwide. Most of those afflicted are dependent on staple crops for their sustenance. Importantly, these crops can be enriched (i.e. ‘biofortified’) with micronutrients using plant breeding and/ or transgenic strategies, because micronutrient enrichment traits exist within their genomes that can to used for substantially increasing micronutrient levels in these foods without negatively impacting crop productivity. Furthermore, ‘proof of concept’ studies have been published using transgenic approaches to biofortify staple crops (e.g. high b-carotene ‘golden rice’ grain, high ferritin-Fe rice grain, etc). In addition, micronutrient element enrichment of seeds can increase crop yields when sowed to micronutrient-poor soils, assuring their adoption by farmers. Bioavailability issues must be addressed when employing plant breeding and/or transgenic approaches to reduce micronutrient malnutrition. Enhancing substances (e.g. ascorbic acid, S-containing amino acids, etc) that promote micronutrient bioavailability or decreasing antinutrient substances (e.g. phytate, polyphenolics, etc) that inhibit micronutrient bioavailability, are both options that could be pursued, but the latter approach should be used with caution. The world’s agricultural community should adopt plant breeding and other genetic technologies to improve human health, and the world’s nutrition and health communities should support these efforts. Sustainable solutions to this enormous global problem of ‘hidden hunger’ will not come without employing agricultural approaches.

Biofortification - a sustainable agricultural strategy for reducing micronutrient malnutrition in the global south.

Abstract: Minerals and vitamins in food staples eaten widely by the poor may be increased either through conventional plant breeding or through use of transgenic techniques, a process known as biofortification. HarvestPlus seeks to develop and distribute cultivars of food staples (rice [Oryza sativa L.], wheat [Triticum aestivum L.], maize [Zea mays L.], cassava [Manihot esculenta Crantz], pearl millet [Pennisetum americanum Leeke], beans [Phaseolus vulgaris L.], sweet potato [Ipomoea batatas L.]) that are high in Fe, Zn, and provitamin A through an interdisciplinary global alliance of scientific institutions and implementing agencies in developing and developed countries. Biofortified crops offer a rural-based intervention that, by design, initially reaches these more remote populations, which comprise a majority of the undernourished in many countries, and then penetrates to urban populations as production surpluses are marketed. Thus, biofortification complements fortification and supplementation programs, which work best in centralized urban areas and then reach into rural areas with good infrastructure. Initial investments in agricultural research at a central location can generate high recurrent benefits at low cost as adapted biofortified cultivars become widely available in countries across time at low recurrent costs. Overall, three things must happen for biofortification to be successful. First, the breeding must be successful—high nutrient density must be combined with high yields and high profitability. Second, efficacy must be demonstrated—the micronutrient status of human subjects must be shown to improve when consuming the biofortified cultivars as normally eaten. Third, the biofortified crops must be adopted by farmers and consumed by those suffering from micronutrient malnutrition in significant numbers.

Micronutrient Nutrition of Plants

Abstract: Currently, there are eight trace elements considered to be essential for higher plants, Fe, Zn, Mn, Cu, Ni, B, Mo, and Cl. Possibly, other elements will be discovered to be essential because of recent advances in nutrient solution culture techniques and in the commercial availability of highly sensitive analytical instrumentation for elemental analysis. Much remains to be learned about the physiology of micronutrient absorption, translocation and deposition in plants, and about the functions they perform in plant growth and development. This review briefly summarizes the current knowledge of micronutrients in plants and than presents some new speculations on the mechanisms of micronutrient uptake and translocation in plants.

Addressing micronutrient malnutrition through enhancing the nutritional quality of staple foods: Principles, perspectives and knowledge gaps

Abstract: Five years ago, with international funding, several international agricultural research centers set out to explore the potential to improve the micronutrient quality of some staple food crops Five objectives were identified, and all needed a favorable result if breeding for higher micronutrient density in the staples were to be deemed feasible Useful genetic variation to exploit was needed The traits needed to be manageable in a breeding program (simple screening and high heritability), and stable across a wide range of environments if impact was to be large Above all, the traits needed to be combinable with traits for high yield to ensure that farmers chose the improved lines Finally, it was necessary to show that the new types actually improved the health of humans of low nutrient status representing the target populations The extra nutrients needed to be bioavailable to the gut Today, only this last essential criterion remains to be fully satisfied All other criteria are met to levels that lead us to claim that breeding for nutritional quality is a viable, practicable, and cost-effective strategy to complement existing interventionist strategies Subject to satisfying the last criterion, and results are encouraging, we call for a major funding initiative, and the installation of a new paradigm for 21st century agriculture: one espousing food systems that are highly productive, sustainable, and nutritious This paper reviews the case for and the rationale behind the project that is underway, gives an overview of the results to date and looks at the critical issues that still remain to be confronted

Trace elements in soils and plants

Abstract: Chapter 1 The Biosphere Chapter 2 The Anthroposphere Introduction Air Pollution Water Pollution Soil Plants Chapter 3 Soils and Soil Processes Introduction Weathering Processes Pedogenic Processes Chapter 4 Soil Constituents Introduction Trace Elements Minerals Organic Matter Organisms in Soils Chapter 5 Trace Elements in Plants Introduction Absorption Translocation Availability Essentiality and Deficiency Toxicity and Tolerance Speciation Interaction Chapter 6 Elements of Group 1 (Previously Group Ia) Introduction Lithium Rubidium Cesium Chapter 7 Elements of Group 2 (Previously Group IIa) Beryllium Strontium Barium Radium Chapter 8 Elements of Group 3 (Previously Group IIIb) Scandium Yttrium Lanthanides Actinides Chapter 9 Elements of Group 4 (Previously Group IVb) Titanium Zirconium Hafnium Chapter 10 Elements of Group 5 (Previously Group Vb) Vanadium Niobium Tantalum Chapter 11 Elements of Group 6 (Previously Group VIb) Chromium Molybdenum Tungsten Chapter 12 Elements of Group 7 (Previously Group VIIb) Manganese Technetium Rhenium Chapter 13 Elements of Group 8 (Previously Part of Group VIII) Iron Ruthenium Osmium Chapter 14 Elements of Group 9 (Previously Part of Group VIII) Cobalt Rhodium Iridium Chapter 15 Elements of Group 10 (Previously Part of Group VIII) Nickel Palladium Platinum Chapter 16 Elements of Group 11 (Previously Group Ib) Copper Silver Gold Chapter 17 Trace Elements of Group 12 (Previously of Group IIb) Zinc Cadmium Mercury Chapter 18 Elements of Group 13 (Previously Group IIIa) Boron Aluminum Gallium Indium Thallium Chapter 19 Elements of Group I4 (Previously Group IVa) Silicon Germanium Tin Lead Chapter 20 Elements of Group 15 (Previously Group Va) Arsenic Antimony Bismuth Chapter 21 Elements of Group 16 (Previously Group VIa) Selenium Tellurium Polonium Chapter 22 Elements of Group 17 (Previously Group VIIa) Fluorine Chlorine Bromine Iodine

Organic acids in the rhizosphere: a critical review

Abstract: Organic acids, such as malate, citrate and oxalate, have been proposed to be involved in many processes operating in the rhizosphere, including nutrient acquisition and metal detoxification, alleviation of anaerobic stress in roots, mineral weathering and pathogen attraction. A full assessment of their role in these processes, however, cannot be determined unless the exact mechanisms of plant organic acid release and the fate of these compounds in the soil are more fully understood. This review therefore includes information on organic acid levels in plants (concentrations, compartmentalisation, spatial aspects, synthesis), plant efflux (passive versus active transport, theoretical versus experimental considerations), soil reactions (soil solution concentrations, sorption) and microbial considerations (mineralization). In summary, the release of organic acids from roots can operate by multiple mechanisms in response to a number of well-defined environmental stresses (e.g., Al, P and Fe stress, anoxia): These responses, however, are highly stress- and plant-species specific. In addition, this review indicates that the sorption of organic acids to the mineral phase and mineralisation by the soil's microbial biomass are critical to determining the effectiveness of organic acids in most rhizosphere processes.

Phytoremediation: A Novel Strategy for the Removal of Toxic Metals from the Environment Using Plants

Abstract: Toxic metal pollution of waters and soils is a major environmental problem, and most conventional remediation approaches do not provide acceptable solutions. The use of specially selected and engineered metal-accumulating plants for environmental clean-up is an emerging technology called phytoremediation. Three subsets of this technology are applicable to toxic metal remediation: (1) Phytoextraction--the use of metal-accumulating plants to remove toxic metals from soil; (2) Rhizofiltration--the use of plant roots to remove toxic metals from polluted waters; and (3) Phytostabilization--the use of plants to eliminate the bioavailability of toxic metals in soils. Biological mechanisms of toxic metal uptake, translocation and resistance as well as strategies for improving phytoremediation are also discussed.

N : P ratios in terrestrial plants: variation and functional significance

Abstract: Contents Summary I Introduction II Variability of N : P ratios in response to nutrient supply III Critical N : P ratios as indicators of nutrient limitation IV Interspecific variation in N : P ratios V Vegetation properties in relation to N : P ratios VI Implications of N : P ratios for human impacts on ecosystems VII Conclusions Acknowledgements References Summary Nitrogen (N) and phosphorus (P) availability limit plant growth in most terrestrial ecosystems. This review examines how variation in the relative availability of N and P, as reflected by N : P ratios of plant biomass, influences vegetation composition and functioning. Plastic responses of plants to N and P supply cause up to 50-fold variation in biomass N : P ratios, associated with differences in root allocation, nutrient uptake, biomass turnover and reproductive output. Optimal N : P ratios – those of plants whose growth is equally limited by N and P – depend on species, growth rate, plant age and plant parts. At vegetation level, N : P ratios 20 often (not always) correspond to N- and P-limited biomass production, as shown by short-term fertilization experiments; however long-term effects of fertilization or effects on individual species can be different. N : P ratios are on average higher in graminoids than in forbs, and in stress-tolerant species compared with ruderals; they correlate negatively with the maximal relative growth rates of species and with their N-indicator values. At vegetation level, N : P ratios often correlate negatively with biomass production; high N : P ratios promote graminoids and stress tolerators relative to other species, whereas relationships with species richness are not consistent. N : P ratios are influenced by global change, increased atmospheric N deposition, and conservation managment.