Explore the vast range of titles available.

The moringa tree Moringa oleifera is a fast-growing, drought-resistant tree cultivated across the lowland dry tropics worldwide for its nutritious leaves. Despite its nutritious reputation, there has been no systematic survey of the variation in leaf nutritional quality across M. oleifera grown worldwide, or of the other species of the genus. To guide informed use of moringa, we surveyed protein, macro-, and micro- nutrients across 67 common garden samples of 12 Moringa taxa, including 23 samples of M. oleifera. Moringa oleifera, M. concanensis, M. stenopetala, an M. concanensis X oleifera hybrid, and M. longituba were highest in protein, with M. ruspoliana having the highest calcium levels. A protein-dry leaf mass tradeoff may preclude certain breeding possibilities, e.g. maximally high protein with large leaflets. These findings identify clear priorities and limitations for improved moringa varieties with traits such as high protein, calcium, or ease of preparation.

Cadmium (Cd) is a toxic heavy metal that can cause severe health issues if ingested. Certain varieties of rice can accumulate high levels of the metal in edible tissues thereby transferring the toxin into the food chain. As chemical analogs, interactions between the essential mineral zinc and the toxic heavy metal cadmium play an important role in regulating the transport of both minerals to rice grains. Understanding these interactions is crucial for limiting cadmium and increasing zinc transfer to the food chain. Previous studies have reported conflicting results suggesting synergistic and antagonistic relationships between the minerals. The goal of this work was to identify the effect of external cadmium and zinc on the uptake and translocation of both minerals from roots to grains of rice that differ in grain cadmium concentrations. The results showed that a higher input of external zinc increased cadmium translocation and accumulation to the grain in two of three varieties, while external cadmium does not influence zinc accumulation. Cadmium synergy and antagonism with other essential minerals were also examined and the effects differed between rice lines. Our results showed that the differential expression of the transport proteins OsNramp5, OsHMA2, and OsHMA3 as well as genes involved in the synthesis of glutathione and phytochelatin could have contributed to differences in grain Cd accumulation. These results add to the knowledge of cadmium and zinc partitioning in one of the most consumed plant foods in the world and can assist fortification efforts to establish rice lines that are both safe and nutritious.

Millions of people around the world rely on rice (Oryza sativa) for a significant portion of daily calories, but rice is a relatively poor source of essential micronutrients like iron and zinc. Rice has been shown to accumulate alarmingly high concentrations of toxic elements, such as cadmium. Cadmium in foods can lead to renal failure, bone mineral density loss, cancer, and significant neurotoxicological effects. Several strategies to limit cadmium and increase micronutrient density in staple food crops like rice have been explored, but even when cadmium concentrations are reduced by a management strategy, total cadmium levels in rice grain are an unreliable means of estimating human health risk because only a fraction of the minerals in grains are bioaccessible. The goal of this work was to assess the influence of cadmium and zinc supplied to plant roots on the bioaccessibility of cadmium and essential minerals from grains of three rice lines (GSOR 310546/low grain Cd, GSOR 311667/medium grain Cd, and GSOR 310428/high grain Cd) that differed in grain cadmium accumulation. Treatments consisted of 0 μM Cd + 2 μM Zn (c0z2), 1 μM Cd + 2 μM Zn (c1z2), or 1 μM Cd + 10 μM Zn (c1z10). Our results revealed that an increased grain cadmium concentration does not always correlate with increased cadmium bioaccessibility. Among the three rice lines tested, Cd bioaccessibility increased from 2.5% in grains from the c1z2 treatment to 17.7% in grains from the c1z10 treatment. Furthermore, Cd bioccessibility in the low-Cd-accumulating line was significantly higher than the high line in c1z10 treatment. Zinc bioaccessibility increased in the high-cadmium-accumulating line when cadmium was elevated in grains, and in the low-cadmium line when both cadmium and zinc were increased in the rice grains. Our results showed that both exogenous cadmium and elevated zinc treatments increased the bioaccessibility of other minerals from grains of the low- or high-grain cadmium lines of rice. Differences in mineral bioaccessibility were dependent on rice line. Calculations also showed that increased cadmium bioaccessibility correlated with increased risk of dietary exposure to consumers. Furthermore, our results suggest that zinc fertilization increased dietary exposure to cadmium in both high and low lines. This information can inform future experiments to analyze genotypic effects of mineral bioavailability from rice, with the goal of reducing cadmium absorption while simultaneously increasing zinc absorption from rice grains.

Several grain legumes are staple food crops that are important sources of minerals for humans; unfortunately, our knowledge is incomplete with respect to the mechanisms of translocation of these minerals to the vegetative tissues and loading into seeds. Understanding the mechanism and partitioning of minerals in pea could help in developing cultivars with high mineral density. A mineral partitioning study was conducted in pea to assess whole-plant growth and mineral content and the potential source-sink remobilization of different minerals, especially during seed development. Shoot and root mineral content increased for all the minerals, although tissue-specific partitioning differed between the minerals. Net remobilization was observed for P, S, Cu, and Fe from both the vegetative tissues and pod wall, but the amounts remobilized were much below the total accumulation in the seeds. Within the mature pod, more minerals were partitioned to the seed fraction (>75%) at maturity than to the pod wall for all the minerals except Ca, where only 21% was partitioned to the seed fraction. Although there was evidence for net remobilization of some minerals from different tissues into seeds, continued uptake and translocation of minerals to source tissues during seed fill is as important, if not more important, than remobilization of previously stored minerals.

Increasing the amount of bioavailable micronutrients such as iron and zinc in plant foods for human consumption is an international goal, intended especially for developing countries where micronutrient deficiencies are an ongoing health risk. Legume seeds have the potential to provide the essential nutrients required by humans, but concentrations of several minerals are low when compared to other foods. In order to increase seed mineral concentrations, it is important to understand the genes and processes involved in mineral distribution within the plant. The main objectives of this study were to use a Medicago truncatula recombinant inbred population (Jemalong-6 × DZA 315.16) to determine loci governing seed mineral concentrations, seed mineral content, and average seed weight, and to use these loci to propose candidate genes whose expression might contribute to these traits. Ninety-three lines in 2004 and 169 lines in 2006 were grown for seed harvest and subsequent analysis of seed Ca, Cu, Fe, K, Mg, Mn, P, and Zn concentrations and content. Quantitative trait loci (QTL) cartographer was used to identify QTL using composite interval mapping (CIM). CIM identified 46 QTL for seed mineral concentration, 26 for seed mineral content, and 3 for average seed weight. At least one QTL was detected for each mineral trait, and colocation of QTL for several minerals was found in both years. Results comparing seed weight with seed mineral concentration and content QTL demonstrate that seed size can be an important determinant of seed mineral concentration. The identification, in this model legume, of transgressive segregation for nearly all the minerals suggests that allelic recombination of relevant mineral-related genes in agronomic legumes could be a successful strategy to increase seed mineral concentrations above current levels.

Cadmium is a nonessential, toxic, heavy metal which enters the environment due to anthropogenic activities. Cadmium is toxic to both plants and animals. Cadmium accumulates in edible portions of crop plants and also exceeds the permissible limits. Since Cd accumulates in edible portions, the main source of Cd for animals and humans is through plant foods. Food chain transfer of Cd also poses a potential risk to animals and humans. Zinc, on the other hand is an essential element to both plants and animals. However, elevated concentrations of Zn can also be phytotoxic to plants. Cadmium and Zn are presumed to be transported and remobilized in the plants via similar pathways. The objectives of both the studies were to examine the transport and accumulation of Cd by two different plant species and how this accumulation can impact the consumers of this plant tissue. The field study was conducted at a Cd contaminated site at Crab Orchard National Wildlife Refuge. The main goal of this study was to assess the impact of Cd accumulation on the growth of the dominant grass species on this site, D. clandestinum and the impact on its consumer (deer). The results showed that D. clandestinum accumulated an elevated concentration of Cd in the vegetative tissues. However, evidence from this study does not indicate any immediate risk to the deer. The second study used Brassica juncea to study how timing of Cd exposure and interactions with Zn influenced the transport and accumulation in different tissues, especially seeds. From this study it is apparent that seed set stage is the critical in the plant's life cycle in determining Cd accumulation in seeds. Cd uptake was affected by Zn only in roots. Zinc and Cd did not have any protective effect in the translocation and accumulation of Cd to the seeds. Although Cd and Zn reached phytotoxic concentrations in the tissues, it does not pose any risk to humans. In fact, concentrations of Zn in the seeds are higher than the concentrations usually found in cereals which might be beneficial due to increase in micronutrient density in seeds.