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Can. Ent. 107: 1233-1252 (1975) Several species of wireworms were attracted to germinating wheat, air from flasks of germinating wheat, decomposing oatmeal, commercial CO, and, in addition, germinating seeds of eight other cultivated plant species. Larvae located a biological or experimental source of CO, by a directed movement along CO, gradients, from distances up to 20 cm.Methods and apparatus for measuring small CO, gradients, using gas chromatography and mass spectrometry, are described. Ctenicera destructor (Brown) larvae apparently responded to CO, gradients between glass plates, that ascended on the average by 0.0028 (soil) and 0.0058 (agar)/cm over a distance of from 12 to 16 cm. The "sensitivity threshold" was calculated as being 1-2 ppm over the distance involved in one deflection of the head during klinotactic orientation. Attractancy was observed within a range of CO, concentration from about 0.0368 to 1.5%. Repellent effects did not appear to be only related to concentration, but possibly were due to steepness of the gradient and(or) previous exposure to CO,.Passing an air stream from germinating grain over a KOH solution eliminated the attractancy of the grain by removing the CO, and possibly other undetected attractants. A small percentage of C. destructor larvae apparently oriented to an ethylene source, but it was concluded the CO, was the most important if not the only attractant from germinating wheat seeds. General MethodsThe wireworms used for the majority of the experiments were Ctenicera destructor (Brown) and Agriotes obscurus-lineatus (L.). Observations were also made on Limonius californicus (Mannerheim) and Hypolithus bicolor Eschscholtz. The Agriotes larvae were collected from pastures in Switzerland, near Wadenswil and Horgen in the autumn and near Egnach in the spring. The remaining species mentioned above were collected near Saskatoon, Sask.The A. obscurus-lineatus, L. californicus, and H . bicolor larvae were brought to room temperature (22-25°C) 24-48 h before being used in experiments. The C . destructor larvae were put in individual dishes at 15OC for at least 2 weeks and then transferred to room temperature (ca. 25°C) for testing. None of the larvae was fed before any of the experiments.The response of larvae to the stimulus offered by a germinating seed or a source of CO, was observed and recorded following the general method of Klingler (1958). A thin layer of soil was sprinkled on a 3 0 x 30 cm glass plate on which a germinating seed or seeds had been placed. The soil and seed were then covered by a second glass plate held 2.4 mm above the bottom plate by supports in each comer. If CO, was used as the stimulus, a No. 22 hypodermic needle 15 cm long was taped to the bottom of the top plate at any desired point between the plates before the soil was applied. The hypodermic needle was connected to a 125-or a 50-ml flask filled with COZ4 and with an automatic syringe which allowed injection speeds ranging from 0.2 to 60 mllh.Larvae to be tested for a response were introduce...

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Three anthocyanin regulatory genes of maize (Zea mays; Lc, B-Peru, and C1) were introduced into alfalfa (Medicago sativa) in a strategy designed to stimulate the flavonoid pathway and alter the composition of flavonoids produced in forage. Lc constructs included a full-length gene and a gene with a shortened 5Ј-untranslated region. Lc RNA was strongly expressed in Lc transgenic alfalfa foliage, but accumulation of red-purple anthocyanin was observed only under conditions of high light intensity or low temperature. These stress conditions induced chalcone synthase and flavanone 3-hydroxylase expression in Lc transgenic alfalfa foliage compared with non-transformed plants. Genotypes containing the Lc transgene construct with a full-length 5Ј-untranslated region responded more quickly to stress conditions and with a more extreme phenotype. High-performance liquid chromatography analysis of field-grown tissue indicated that flavone content was reduced in forage of the Lc transgenic plants. Leucocyanidin reductase, the enzyme that controls entry of metabolites into the proanthocyanidin pathway, was activated both in foliage and in developing seeds of the Lc transgenic alfalfa genotypes. Proanthocyanidin polymer was accumulated in the forage, but (ϩ)-catechin monomers were not detected. B-Peru transgenic and C1 transgenic populations displayed no visible phenotypic changes, although these transgenes were expressed at detectable levels. These results support the emerging picture of Lc transgene-specific patterns of expression in different recipient species. These results demonstrate that proanthocyanidin biosynthesis can be stimulated in alfalfa forage using an myc-like transgene, and they pave the way for the development of high quality, bloat-safe cultivars with ruminal protein bypass.The ability to manipulate flavonoid biosynthesis in crop plants is gaining rapidly in importance as new economically important uses are found in the areas of nutraceuticals, food quality, and feed quality. The introduction of proanthocyanidin (PA, a flavonoid polymer) into alfalfa (Medicago sativa) forage is particularly important to ruminant livestock producers. Proanthocyanidins eliminate pasture bloat, improve the efficiency of conversion of plant protein into animal protein (ruminal protein bypass), reduce greenhouse gases, reduce gastrointestinal parasites, and inhibit insect feeding (Waghorn, 1990; Neizen et al., 1995 Neizen et al., , 1998 Aerts et al., 1999; Muir et al., 1999; McMahon et al., 2000). Alfalfa forage (leaf and stem tissues) accumulate anthocyanins only at senescence or locally under some stress conditions such as insect feeding (Goplen et al., 1980). No known conditions induce proanthocyanidins in alfalfa forage, although they are structurally related to anthocyanins. However, these compounds do accumulate in seed coats (Koupai-Abyazani et al., 1993).Anthocyanins and proanthocyanidins share early and middle steps of the flavonoid biosynthetic pathway, including chalcone synthase (CHS), chalcone isomerase, flavan...

Samples of commercially prepared white, whole wheat, flax, and multigrain breads were analyzed by a rapid RP-HPLC method for the presence of the lignan secoisolariciresinol diglucoside (SDG). SDG was detected only in products containing flax, with concentrations ranging from 0.06 to 1.98 microM/g of DW (19-602 microM/loaf). Full-fat flax meal, powdered aqueous alcohol extracts of flax seed, and SDG were added to a white bread mix and baked into loaves in a domestic bread maker. Quantitative recovery of SDG from the test breads was observed when SDG was added; however, when flax meal or aqueous alcohol extracts were added, only 73-75% of the theoretical yield of SDG was recovered. SDG was also detected in commercially prepared flax cookies, bagels, and muffins with concentrations ranging from 0.26 to 2.93 microM/g of DW. The extent of grinding of the flax seed was also shown to have a significant effect on the recovery of SDG from both flax meal breads and baked goods, with extraction of SDG from finely ground samples greater than that from course material.

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The flaxseed lignans secoisolariciresinol (SECO) and its diglucoside secoisolariciresinol diglucoside (SDG) are reported to have a number of health benefits associated with their consumption that have in part been attributed to their antioxidant properties. In this study the relative antioxidant capacity of the flaxseed lignans vs. BHT was determined in two model systems. First, an antioxidant stoichiometric value was determined for SECO and SDG in a liposomal system as a mimic of lipid peroxidation. Stoichiometric values for SECO (1.5) and SDG (1.2) vs. BHT (2.0) were measured from the lag time for the formation of conjugated dienes; all values were significantly different (P < 0.01). Second, the ability of flaxseed lignans to prevent oxidative degradation of canola oil was determined. Samples were stored at room temperature and analyzed at 30-d intervals over 120 d using a Rancimat TM analyzer. The lignans prevented degradation of canola oil, as measured by induction time, in a concentration-dependent manner. Although SECO demonstrated a trend for better protection than either SDG or polymer containing SDG, they were not significantly different (P > 0.01). There was also no significant difference between SECO or SDG and BHT, suggesting flaxseed lignans may be good alternatives to minimize rancidity in oil-based food products.