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La lechuga es una hortaliza de amplio consumo popular, por sus beneficios para la salud y la nutrición. Se estudiaron los cambios en calidad de cuatro variedades (Alpha, Parris Island, Graziella y Lollo Rossa) almacenadas durante 12 días a 5,5 ºC y 90 % HR. Se determinaron contenido de agua, sólidos solubles totales (SST), acidez titulable (AT), vitamina C, fenoles totales, polifenol oxidasa (PFO), color y textura. Las variedades de lechuga tuvieron tasas diferentes de pérdida de agua y modificaciones en los SST y la AT. La variedad Graziella tuvo el más alto nivel de vitamina C. El contenido de fenoles totales se redujo significativamente en el día 12 de almacenamiento. No se observaron alteraciones en la actividad de la PFO excepto en Lollo Rossa. El análisis Biplot mostró correlaciones positivas y negativas de las coordenadas L*, a* y b*, con lo cual se observó una clara definición de dos grupos de lechuga: verde y roja. Se hizo evidente la modificación en la tonalidad del color de acuerdo con la posición de las hojas. Se registraron cambios en la textura al final del almacenamiento, que no alteraron la calidad del follaje. Si bien los parámetros evaluados varían según la variedad, la refrigeración contribuye a mantener las propiedades del vegetal para el consumo directo.

Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection against carcinogenesis, mutagenesis, and other forms of toxicity of electrophiles and reactive forms of oxygen. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism. Thus, edible plants belonging to the family Cruciferae and genus Brassica (e.g., broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.g., sulforaphane or 4-methylsulfinylbutyl isothiocyanate) are very potent inducers of phase 2 enzymes. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10-100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants. Glucosinolates and isothiocyanates can be efficiently extracted from plants, without hydrolysis of glucosinolates by myrosinase, by homogenization in a mixture of equal volumes of dimethyl sulfoxide, dimethylformamide, and acetonitrile at -50 degrees C. Extracts of 3-day-old broccoli sprouts (containing either glucoraphanin or sulforaphane as the principal enzyme inducer) were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz(a)anthracene-treated rats. Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products (e.g., indole-3-carbinol) that can enhance tumorigenesis. Hence, small quantities of crucifer sprouts may protect

Amaranth is a very important vegetable worldwide. Its leaves are consumed and the seeds are processed into various food products. Its production in the tropics is threatened by low yields which has a major impact on global production. A research aimed at improving the yield of this vegetable was carried out at Lady Bird organic farm Broga, Semenyih, Selangor, Malaysia by studying the effect of genotype and organic fertilizer on the following growth indicators, red:far red ratio below canopy, stomatal conductance, leaf temperature, and dry weight. These growth indicators were monitored on a weekly basis over a period of six weeks. Three genotypes namely, Amaranthus caudatus, 3388 (green round leaf), Amaranthus caudatus, 3233 (green long leaf) and Amaranthus cruentus, 888 (red leaf) were grown on soils to which organic fertilizer was added at three different application rates (0 t/ha, 7.5 t/ha and 15 t/ha). There was no significant interaction effect of genotype and organic fertilizer on the growth indicators; however, each of these factors had significant effect on the growth of amaranth. A strong negative correlation occurred between dry weight and red:far red ratio below canopy likewise, between stomatal conductance and leaf temperature. Over a cultivation period of five weeks, the green long leaf genotype was superior showing that it is better adapted to growing in the rainforest agro ecological zone of Malaysia than the other two genotypes. Organic fertilizer application at a rate of 15 t/ha produced the lowest leaf temperature, after 4 weeks of cultivation implying better water status than 0 t/ha and 7.5 t/ha application rates. This study clearly shows that genotype and organic fertilizer have significant effect on the growth of amaranth. Therefore, these factors can be manipulated in order to enhance amaranth production.

Two pot and two open-field experiments were conducted to determine the influence of N fertilisation on nitrate accumulation, yield, and leaf quality of turnip greens (“Nabiças”, Brassica rapa var. rapa). The pot experiments were conducted: (1) in a controlled environment (24 h photoperiod at 250±25 μmol s-1 m-2, and 20±1 °C ), and (2) outdoors (315 w m-2 mean solar radiation, and daily mean air temperature between 19 and 26 °C). The response of plant biomass to N from 0 to 250 g m-3 of pot-soil, in each of the two experiments, was characterised by a steep increase in weight until the level of N reached 100 g m-3, with a tendency to stabilisation thereafter. There was a clear turning point around 100 g m-3 N, beyond which plant biomass did not significantly increase in response to N application. When fertilisation with N was increased from at 100 to 250 g m-3, plant fresh weight increased by 7.4 and 8.6% and nitrate concentration by 279 and 1315%, respectively, in both growth-room and outdoors pot experiments, showing that turnip greens may easily reach conditions of luxury consumption of N. In the two open-field experiments, turnip plants were grown in a clay soil, in winter and in spring at Lisbon, Portugal. Increasing N fertilisation from 0 to 200 kg ha-1 resulted in plants with higher fresh weight both in winter and spring. Plant nitrate concentration in winter was higher than in spring at the same applied N. The increase of plant fresh weight in response to N had a clear asymptotic tendency at N exceeding 160 kg ha-1, but the increase of leaf nitrate had a linear trend showing a clear tendency for nitrate accumulation in the leaves. N induced a darker green leaf colour but had no effect on leaf taste and texture. Increasing N fertilisation up to 200 kg ha-1 seemed to be an effective means of improving yield and quality of turnip greens and of shortening the cropping cycle.

In addition to the seeds consumed as a pseudocereal, amaranths provide important edible greens. In the Sierra Norte de Puebla, Mexico, the management and utilization of amaranths occur within a wide variety of environmental, biological and cultural contexts. This paper presents both the results of ethnobotanical exploration in this region and the comparison of different species and races of amaranths used as greens that were grown in common experimental garden plots in Chalco, Mexico. Ethnobotanical exploration, cultural practices and growth analysis suggests that these plants have been selected for their use as leafy vegetables. The experimental data support the divergence of amaranths used for greens from those used principally for edible seed. /// Los amarantos además de proporcionar semillas para su uso como pseudocereal producen hojas comestibles. En la región de la Sierra Norte de Puebla, la utilización y el manejo de los amarantos tiene lugar dentro de una enorme variedad de condiciones ambientales, biológicas y culturales. En este trabajo se presentan los resultados obtenidos a partir de la exploración etnobotánica realizada en la Sierra Norte de Puebla asi como los datos obtenidos a partir de un estudio de análisis de crecimiento llevadp a cabo en Chalco. Estado de México, en donde se comparan diferentes especies y razas de amaranto que se usan a manera de verdura. La exploración etnobotánica, las prácticas culturales y el estudio de análisis de crecimiento sugieren que estas plantas han sido seleccionadas para ser usadas como verdura y que difieren de las que se usan como grano.

Studies by means of scanning electron microscope (SEM) of primary xylem of Nymphaeaceae have revealed diversity in vessels and rudimentary expressions of pore formation on end walls of vessel elements. A similar situation is true in Cabombaceae. In Brasenia schreberi, vessels occur not only in roots but also in rhizomes. Vessels in roots have lignified helical or annular bands only at the ends of the vessel elements; central portions of the elements have diminished versions of the thickenings, lacking borders and lignification-a configuration hitherto unreported for vascular plants. This may be the first demonstrated instance of a midpoint in reduction of tracheary tissue in relation to the aquatic habitat. Perforation plates in roots consist of a series of pores of various sizes in primary wall areas between the lignified bands; pores are fewer in the perforation plates of tracheary elements of rhizomes. Vessels in Brasenia likely illustrate early stages in vessel origin. Because the patterns of vessel structure now available by means of SEM are so different from those hitherto figured for primary xylem of dicotyledons currently placed in basal portions of cladograms, we are extending our studies to primary xylem of other vascular plants likely to show incipient stages of vessel evolution. Evidence now available forces us to envision vessel origin in angiosperms in terms of formation of numerous pores on end walls, rather than elimination of entire pit membranes at the outset, and this poses new questions about the nature of conduction and embolism spread in species with porose end walls

The ability of a supplement of local, cooked green leaves to support vitamin A nutriture of anemic, lactating rural Indonesian women was tested using increments in carotenoid and retinol content in plasma and breast milk as indices of bioavailability and bioconversion, respectively. While beta-carotene provided in a simple matrix of a fortified cracker produced substantial improvements in both vitamin A and carotenoid status, an equivalent amount from stir-fried vegetables had a negligible effect

Reversed-phase liquid chromatography hyphenated with inductively coupled plasma mass spectrometry (LC-ICP-MS) was used for mercury speciation analysis in food samples. A short chromatographic column and a mobile phase containing 0.02 mol/l CH3COONH4 + 0.2% (v/v) 2-mercaptoethanol (2-ME) + 1% (v/v) CH3OH were applied. A repeated extraction of samples with hydrochloric acid/2-ME solution (1 mol/l HCl + 0.2% (v/v) 2-ME) was applied as the isolation step. The results were satisfactory for most food matrices (fish, shellfish, plant materials). Conversely, to analyse high-protein animal matrices, which contain mostly the inorganic form of mercury, a procedure including partial hydrolysis using hydrochloric acid should be used. For methylmercury and inorganic divalent mercury, the LOQ values of 0.3 and 2 ng/g, respectively, can be achieved if precautionary measures against contamination are fulfilled. The method was applied for the determination of methylmercury and inorganic divalent mercury in fish, vegetables, herbs and cereal products.