Dry legumes are staple and potentially functional food, being a good source of polyphenols, flavonoids, and antioxidant activity. The objective of this study was to determine the total polyphenol content (TPC), total flavonoid content (TFC), and their relation with antioxidant capacity in 17 chickpea lines having colored seed coats (black, red, brown, green, rubiginous, gray, yellow, cream, or beige). The seed coat usually contains more than 95% of these compounds. In this study, both TPC and TFC varied significantly among different lines and were highly correlated to antioxidant activity. Colored seeds contained up to 13-, 11-, and 31-fold more TPC, TFC, and antioxidant activity, respectively, than cream- and beige-color seeds. Thus, colored chickpea could be a potentially functional food in addition to its traditional role of providing dietary proteins and dietary fibers.

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Electrical potentials in cell walls ( Wall ) and at plasma membrane surfaces ( PM ) are determinants of ion activities in these phases. The PM plays a demonstrated role in ion uptake and intoxication, but a comprehensive electrostatic theory of plant-ion interactions will require further understanding of Wall . Wall from potato (Solanum tuberosum) tubers and wheat (Triticum aestivum) roots was monitored in response to ionic changes by placing glass microelectrodes against cell surfaces. Cations reduced the negativity of Wall with effectiveness in the order AlThis order resembles substantially the order of plant-root intoxicating effectiveness and indicates a role for both ion charge and size. Our measurements were combined with the few published measurements of Wall , and all were considered in terms of a model composed of Donnan theory and ion binding. Measured and model-computed values for Wall were in close agreement, usually, and we consider Wall to be at least proportional to the actual Donnan potentials. Wall and PM display similar trends in their responses to ionic solutes, but ions appear to bind more strongly to plasma membrane sites than to readily accessible cell wall sites. Wall is involved in swelling and extension capabilities of the cell wall lattice and thus may play a role in pectin bonding, texture, and intercellular adhesion.The cell wall (CW) is composed of various crosslinked units (macrofibrils, microfibrils, micelles, cellulose units, and linked agents such as neutral sugars, pectin, proteins, and ions; Cosgrove, 1997; Buchanan et al., 2000). The CW behaves as an ion exchanger where the fixed CW charges interact with exchangeable ions in the surrounding solution (Briggs and Robertson, 1957; Gillet and Lefèbvre, 1981; Sentenac and Grignon, 1981; Irwin et al., 1985; Richter and Dainty, 1989a, 1989b, 1990a, 1990b Grignon and Sentenac, 1991). The net CW charge is negative and results from weakly dissociating acidic groups having pK a values similar to those of polyGalUA, the principal origin of the negative charges (Ritchie and Larkum, 1982; Saftner and Raschke, 1981; Richter and Dainty, 1989a; Buchanan et al., 2000). Some positive charges occur too, mainly associated with CW proteins (Cassab and Varner, 1988; Buchanan et al., 2000).The CW determines cell dimensions (Taiz, 1984) and intracellular volume. The volume of the CW is a consequence of the dimensions of its internal spaces, i.e. the distances between the intra-CW units (Shomer et al., 1984; Shomer and Levy, 1988), which are determined by the repulsive strengths of diffuse double layers (Shomer et al., 1991). The swelling of parenchyma CW is restrained by the increase of valence and concentration of the exchangeable ions and with the decrease of the dielectric constant of the bulk solution (Shomer et al., 1991; Shomer, 1995). Although cell expansion and CW extension have been studied comprehensively (Cosgrove, 1997), the properties governing the volume of the CW, from the point of view of the dimensions of its internal spaces...

The broad mite (BM), Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae), is a minute polyphagous mite that has severe effects on the host plant. Mechanisms of BM injury and subsequent plant responses are unclear. In this study we characterized the morphological and molecular reactions of cucumber plants ( Cucumis sativus L. , Cucurbitaceae) to BM infestation. Infested plants showed growth inhibition and a decrease in leaf number and leaf area. There was also an increase in the firmness of the infested leaves, as measured by a texture analyzer. Broad mite feeds on the epidermis, but structural and ultrastructural studies revealed aberrations in the whole leaf tissue. Severe infestation led to a complete loss of epidermis and an increase in mesophyll cell size and number. In transmission electron microscope (TEM) images, the entire epidermal tissue appeared to have collapsed, and the mesophyll cell walls appeared thick and distorted. In the infested leaves, a Northern blot analysis revealed the induction of genes related to the jasmonic acid (JA)/ethylene and salicylic acid (SA) pathways, such as lipoxygenase ( LOX ) and β -1,3 glucanase ( BGL2 ), and an induction of oxidative stress-responsive transcripts, such as peroxidase ( PRX ). Transcript levels of ACC oxidase ( ACO ) that participate in ethylene biosynthesis, remained relatively constant. This work reveals that BM feeding causes dramatic morphological, structural, and ultrastructural changes, along with an induction of genes involved in defense pathways. Further studies are needed to evaluate whether the observed changes in leaf structure and ultrastructure affect the mite, and how the induction of the defense pathways affects the susceptibility of plants to BM infestations.

Abstract--The dispersion of clays is of great importance in determining various soil properties such as hydraulic conductivity. A procedure which involves fixing followed by embedding of clay particles in an epoxy resin is described. This procedure enables the observation of cross sections of clay tactoids under a transmittance electron microscope, and the determination of the number of plates per tactoid. The use of the procedure for the determination of the relation between the exchangeable sodium percentage (ESP) and tactoid size in suspensions of a Na/Ca bentonite system is presented. It was demonstrated that even at ESP 5 significant dispersion already occurs, the average number of plates per tactoid being 6.6 as compared to 16.1 at ESP 0.

Cloud stability in citrus fruit aqueous peel extract (PEX) and the derived serum (SPEX) was studied with respect to endogenous coagulants and the possible involvement of soluble pectin as stabilising agent. Heat treatment of the pectin-degraded SPEX induced the appearance of turbidity as a result of protein coagulation, particularly in the pH range of 3.5-4.5, whereas only slight coagulation occurred without heat treatment. The pectin in non-degraded SPEX therefore inhibited heat coagulation of most of the protein present. Incubation of PEX itself with exogenous depolymerising pectinase (DP) slightly increased its transmittance, and subsequent heat treatment clarified the suspension within a short time, especially at pH 23-44. Under the electron microscope, heat-coagulated proteins from DP-incubated SPEX appeared as dispersed amorphous bodies showing two main types of pattern; the coagulate from a PEX preparation of high oil content appeared as ultramicro-droplets of oil encapsulated within coagulated proteins.The evidence indicates that soluble pectin in PEX preparations affects cloud stability by preventing the coagulation of heat-denatured proteinaceous components; once the pectin is degraded by endogenous and exogenous DP, protein coagulation occurs rapidly on heat treatment, resulting in co-precipitation of the other encapsulated colloidal bodies.

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