Effects of boron and light treatments on the ascorbate concentration of alfalfa sprouts [abstract]

Abstract only availableAlfalfa (Medicago sativa) sprouts are an inexpensive, year-round source of fresh produce. Consumption of sprouts could be further advocated if their nutritional benefits were improved. The purpose of this study was to determine if growing alfalfa sprouts with boron and light treatments will increase the ascorbic acid (vitamin C) content of the sprouts. Alfalfa seeds were germinated for 3 days with and without boron. Both +boron and -boron treatments were grown in the dark or given a 3 hour light treatment. Dark germination of alfalfa with boron increased the ascorbate content of the sprouts by 30% compared to those grown without boron. Light treatment increased ascorbate in both +boron and -boron treatments, but boron did not seem to cause a significant difference in ascorbate among the light treated sprouts. These findings may present a method for increasing the ascorbic acid concentration in dark grown sprouts by germination in the presence of boron.Missouri Fertilizer and Lime Boar

High phosphorus rapidly increase squash root magnesium, sodium and calcium concentration

Abstract only availablePrevious studies in our laboratory have shown a significant impact of phosphorus nutrition on mineral element dynamics in plant roots and shoots (Reinbott and Blevins 1991, 1994, 1999). We hypothesize that increased P availability increases ATP concentration, driving rapid increases in root concentration of several cations by stimulating the proton pump and opening gated ion channels. Considering the rapid turnover of ATP in plant tissues, P-induced changes in root mineral element concentrations should be observed in a relatively short time. Therefore, experiments were designed to evaluate the effect of P on root tissue cation concentrations over the time course of 30 min to 8 hrs. Squash plants were grown hydroponically in a complete nutrient solution (500 µM P) for six days, following by four days with 50 µM P. Treatments of 50 and 500 & µM P were started on day 10 and roots were harvested after 0, 0.5, 1, 2, 4, and 8 hours. Roots were rinsed in DI H2O, blotted, frozen in liquid nitrogen, and freeze-dried. Freeze-dried samples were ground, digested in nitric acid using a closed-vessel microwave system, and macro- and micronutrient concentrations were determined using ICP-OES. As expected, higher P in nutrient solution resulted in higher P concentrations in squash roots. This increase was first observed after 2 hrs. As for other cations, high P increased leaf magnesium, sodium, and calcium concentrations, and decreased zinc and potassium concentrations. Interestingly, the change in concentration of all these elements was observed within 30 min. This is, to our knowledge, the first study showing a short-time impact of P nutrition on root cation composition. It supports the hypothesis of the role of P in cation uptake.Gyeongsang National Universit

Ethylene production, cluster root formation, and localization of iron(III) reducing capacity in Fe deficient squash roots

Dicots and non-graminaceous monocots have the ability to increase root iron(III) reducing capacity in response to iron (Fe) deficiency stress. In squash (Cucurbita pepo L.) seedlings, Fe(III) reducing capacity was quantified during early vegetative growth. When plants were grown in Fe-free solution, the Fe(III) reducing capacity was greatly elevated, reached peak activity on day 4, then declined through day 6. Root ethylene production exhibited a temporal pattern that closely matched that of Fe(III) reducing capacity through day 6. On the 7th day of Fe deficiency, cluster root morphology developed, which coincided with a sharp increase in the root Fe(III) reducing capacity, although ethylene production decreased. Localization of Fe(III) reducing capacity activity was observed during the onset of Fe deficiency and through the development of the root clusters. It was noted that localization shifted from an initial pattern which occurred along the main and primary lateral root axes, excluding the apex, to a final localization pattern in which the reductase appeared only on secondary laterals and cluster rootlets

Characterization of FRO\u3csub\u3e1\u3c/sub\u3e, a Pea Ferric-Chelate Reductase Involved in Root Iron Acquisition

To acquire iron, many plant species reduce soil Fe(III) to Fe(II) by Fe(III)-chelate reductases embedded in the plasma membrane of root epidermal cells. The reduced product is then taken up by Fe(II) transporter proteins. These activities are induced under Fe deficiency. We describe here the FRO1 gene from pea (Pisum sativum), which encodes an Fe(III)-chelate reductase. Consistent with this proposed role, FRO1 shows similarity to other oxidoreductase proteins, and expression of FRO1 in yeast conferred increased Fe(III)-chelate reductase activity. Furthermore, FRO1 mRNA levels in plants correlated with Fe(III)-chelate reductase activity. Sites of FRO1 expression in roots, leaves, and nodules were determined. FRO1 mRNA was detected throughout the root, but was most abundant in the outer epidermal cells. Expression was detected in mesophyll cells in leaves. In root nodules, mRNA was detected in the infection zone and nitrogen-fixing region. These results indicate that FRO1 acts in root Fe uptake and they suggest a role in Fe distribution throughout the plant. Characterization of FRO1 has also provided new insights into the regulation of Fe uptake. FRO1 expression and reductase activity was detected only in Fe-deficient roots of Sparkle, whereas both were constitutive in brz and dgl, two mutants with incorrectly regulated Fe accumulation. In contrast, FRO1 expression was responsive to Fe status in shoots of all three plant lines. These results indicate differential regulation of FRO1 in roots and shoots, and improper FRO1 regulation in response to a shoot-derived signal of iron status in the roots of the brz and dgl mutants

Nutrient interaction effects on yield and chemical composition of spinach and green beans

This report is based upon a thesis submitted by Mr. Blevins as partial fulfillment of a master of science degree from the College of Agriculture, University of Missouri-Columbia--P. [2].Digitized 2007 AES MoU.Includes bibliographical references (pages 22-23)

Adequate Soil Phosphorus Decreases the Grass Tetany Potential of Tall Fescue Pasture

Abstract Grass tetany is a nutritional disease of ruminants caused by low dietary Mg. Previous research has shown that early spring P-fertilization increases the leaf Mg concentration of tall fescue (Festuca arundinacea Schreb.) hay. However, little is known about how P-fertilization alters the mineral concentration of tall fescue under grazing. Our objective was to compare, under grazing, the Mg, K, Ca, and P concentration of tall fescue when soil P was considered either adequate or low

Ethylene production, cluster root formation, and localization of iron(III) reducing capacity in Fe deficient squash roots

Dicots and non-graminaceous monocots have the ability to increase root iron(III) reducing capacity in response to iron (Fe) deficiency stress. In squash (Cucurbita pepo L.) seedlings, Fe(III) reducing capacity was quantified during early vegetative growth. When plants were grown in Fe-free solution, the Fe(III) reducing capacity was greatly elevated, reached peak activity on day 4, then declined through day 6. Root ethylene production exhibited a temporal pattern that closely matched that of Fe(III) reducing capacity through day 6. On the 7th day of Fe deficiency, cluster root morphology developed, which coincided with a sharp increase in the root Fe(III) reducing capacity, although ethylene production decreased. Localization of Fe(III) reducing capacity activity was observed during the onset of Fe deficiency and through the development of the root clusters. It was noted that localization shifted from an initial pattern which occurred along the main and primary lateral root axes, excluding the apex, to a final localization pattern in which the reductase appeared only on secondary laterals and cluster rootlets

More hidden hunger: Special nutrient needs of plants based on their structure and function

Over the years, research has provided us with a great wealth of information that may be useful when considering the macro- and micronutrient needs of specific plants. The objective of the following presentation is to explore some examples of how we can predict special nutrients needs for certain crops based on their structure and metabolism. For example, all steps in protein synthesis require high potassium concentrations and after proteins are synthesized they require potassium for balancing the negative charges of aspartate and glutamate residues. Therefore, high protein crops generally require more potassium than low protein crops. Cell walls of grasses contain less pectin, and therefore less boron and calcium than those of dicots. Thus, boron and calcium requirements of dicots are higher than those of grasses. Plants with C4 photosynthesis can be grouped into different categories based on enzymes involved in C4 acid decarboxylation in bundle sheath cells. In C4 species that utilize NAD-malic enzyme, the release of CO2 for the Calvin cycle depends on manganese activation. Therefore these NAD-malic enzyme plants have a higher manganese requirement for maximum biomass production and photosynthesis than other C4 plants or C3 plants. Soybean plants dependent on biological nitrogen fixation may also have a higher manganese requirement than many other crop plants based on manganese involvement in the metabolism of their root nodule bacteria, and ureide metabolism in their leaves and developing pods. These are only a few examples of how plant structural and functional differences lead to unique macro- or micronutrient needs that may be critical for maximizing crop production and crop quality

Characterization of FRO\u3csub\u3e1\u3c/sub\u3e, a Pea Ferric-Chelate Reductase Involved in Root Iron Acquisition

To acquire iron, many plant species reduce soil Fe(III) to Fe(II) by Fe(III)-chelate reductases embedded in the plasma membrane of root epidermal cells. The reduced product is then taken up by Fe(II) transporter proteins. These activities are induced under Fe deficiency. We describe here the FRO1 gene from pea (Pisum sativum), which encodes an Fe(III)-chelate reductase. Consistent with this proposed role, FRO1 shows similarity to other oxidoreductase proteins, and expression of FRO1 in yeast conferred increased Fe(III)-chelate reductase activity. Furthermore, FRO1 mRNA levels in plants correlated with Fe(III)-chelate reductase activity. Sites of FRO1 expression in roots, leaves, and nodules were determined. FRO1 mRNA was detected throughout the root, but was most abundant in the outer epidermal cells. Expression was detected in mesophyll cells in leaves. In root nodules, mRNA was detected in the infection zone and nitrogen-fixing region. These results indicate that FRO1 acts in root Fe uptake and they suggest a role in Fe distribution throughout the plant. Characterization of FRO1 has also provided new insights into the regulation of Fe uptake. FRO1 expression and reductase activity was detected only in Fe-deficient roots of Sparkle, whereas both were constitutive in brz and dgl, two mutants with incorrectly regulated Fe accumulation. In contrast, FRO1 expression was responsive to Fe status in shoots of all three plant lines. These results indicate differential regulation of FRO1 in roots and shoots, and improper FRO1 regulation in response to a shoot-derived signal of iron status in the roots of the brz and dgl mutants