Selenium accumulation, distribution, and speciation in spineless prickly pear cactus: a drought- and salt-tolerant, selenium-enriched nutraceutical fruit crop for biofortified foods.

The organ-specific accumulation, spatial distribution, and chemical speciation of selenium (Se) were previously unknown for any species of cactus. We investigated Se in Opuntia ficus-indica using inductively coupled plasma mass spectrometry, microfocused x-ray fluorescence elemental and chemical mapping (µXRF), Se K-edge x-ray absorption near-edge structure (XANES) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). µXRF showed Se concentrated inside small conic, vestigial leaves (cladode tips), the cladode vasculature, and the seed embryos. Se K-edge XANES demonstrated that approximately 96% of total Se in cladode, fruit juice, fruit pulp, and seed is carbon-Se-carbon (C-Se-C). Micro and bulk XANES analysis showed that cladode tips contained both selenate and C-Se-C forms. Inductively coupled plasma mass spectrometry quantification of Se in high-performance liquid chromatography fractions followed by LC-MS structural identification showed selenocystathionine-to-selenomethionine (SeMet) ratios of 75:25, 71:29, and 32:68, respectively in cladode, fruit, and seed. Enzymatic digestions and subsequent analysis confirmed that Se was mainly present in a "free" nonproteinaceous form inside cladode and fruit, while in the seed, Se was incorporated into proteins associated with lipids. µXRF chemical mapping illuminated the specific location of Se reduction and assimilation from selenate accumulated in the cladode tips into the two LC-MS-identified C-Se-C forms before they were transported into the cladode mesophyll. We conclude that Opuntia is a secondary Se-accumulating plant whose fruit and cladode contain mostly free selenocystathionine and SeMet, while seeds contain mainly SeMet in protein. When eaten, the organic Se forms in Opuntia fruit, cladode, and seed may improve health, increase Se mineral nutrition, and help prevent multiple human cancers.

Enzymatic modification of chitosan with quercetin and its application as antioxidant edible films.

Quercetin, rutin, naringin, hesperidin and chrysin were tested as substrates for chloroperoxidase to produce reactive quinones to graft onto chitosan. Quercetin and rutin quinones were successfully chemically attached to low molecular weight chitosan. The quercetin-modified chitosan showed an enhancement of plastic, antioxidant and antimicrobial properties as well as of thermal degradability. Finally, chitosan-quercetin films visibly decreased enzymatic oxidation when applied to Opuntia ficus indica cladodes.

Development of the prickly pear cactus Opuntia stricta (Haw.) Haw. (Cactaceae) in vitro in response to the replacement of potassium nitrate for a commercial kno 3 fertilizer / Desenvolvimento da palma Opuntia stricta (Haw.) Haw. (Cactaceae) in vitro em resposta à substituição de nitrato de potássio (P.A.) por fertilizante comercial KNO 3

In micropropagation, potassium nitrate (KNO3), an ACS reagent grade chemical, used in the preparation of growing mediums is expensive and its procurement depends on bureaucratic procedures, as it is controlled by the Brazilian Army. This research to assessed the effect of replacing the ACS KNO3 for a commercially available fertilizer (KNO3- based) on the micropropagation of the prickly pear cactus (Opuntia stricta (Haw.) Haw. cv. Elephant Ear. Treatments used six different fertilizer concentrations (0, 0.5, 1, 1.5, 2 and 2.5 g L-¹) and a control consisting of 1.9 g L-¹ KNO3, as shown in the MS salts. The survival, size and number of sprouts and the value of fresh biomass were evaluated. After seedling acclimation, we assessed the survival, number of sprouts, length, and number of roots, racket formation, average fresh biomass mass, macronutrient absorption and morphological changes of the seedlings. Explants inoculated with fertilizers at concentrations of 0.0; 2.0 and 2.5 g L-¹ did not grow. The response of explants at concentrations of 0.5 and 1.5 g L-¹ of the fertilizer were the same as those developed in a KNO3 medium, and at a concentration of 1.0 g L-¹, in all variables, the means were higher than those of the control medium. Therefore, it showed the feasibility of using fertilizers in the in vitro cultivation of the prickly pear cactus, which may remove bureaucratic barriers and reduce product costs by 99.12%.

Na micropropagação, o nitrato de potássio (KNO3), reagente puro para análise (P.A.), utilizado no preparo dos meios de cultura, possui custo elevado e a sua aquisição depende de trâmites burocráticos, por se tratar de substância controlada pelo Exército Brasileiro. O objetivo deste trabalho foi avaliar o efeito da substituição do KNO3 P.A. por fertilizante comercial (com fonte de KNO3), encontrado livremente no comércio, na micropropagação de palma (Opuntia stricta (Haw.) Haw. cv Orelha de Elefante. Os tratamentos foram de seis concentrações do fertilizante (0; 0,5; 1; 1,5; 2 e 2,5 g L-¹) e um controle constituído de 1,9 g L-¹ de reagente KNO3, conforme mostrado nos sais MS. Avaliou-se a sobrevivência, tamanho e número de brotações do explante, e o valor da biomassa fresca. Após a aclimatização das mudas avaliou-se a sobrevivência, número de brotações, comprimento da parte aérea, número de raízes, formação da raquete, massa média da biomassa fresca, absorção de macronutrientes e alterações morfológicas das mudas. Os explantes inoculados em meio com fertilizantes nas concentrações de 0,0; 2,0 e 2,5 g L-¹ não se desenvolveram. A resposta dos explantes nas concentrações de 0,5 e 1,5 g L-¹ do fertilizante foram iguais aos desenvolvidos em meio contendo KNO3, e na concentração de 1,0 g L-¹, em todas as variáveis, as médias foram superiores em relação as do controle. Dessa forma, constatou-se a viabilidade do uso do fertilizante no cultivo in vitro da palma, o que propiciou a eliminação dos entraves burocráticos e redução no custo de 99,12% na compra do produto.

Development of the prickly pear cactus Opuntia stricta (Haw.) Haw. (Cactaceae) in vitro in response to the replacement of potassium nitrate for a commercial kno 3 fertilizer / Desenvolvimento da palma Opuntia stricta (Haw.) Haw. (Cactaceae) in vitro em resposta à substituição de nitrato de potássio (P.A.) por fertilizante comercial KNO 3

In micropropagation, potassium nitrate (KNO3), an ACS reagent grade chemical, used in the preparation of growing mediums is expensive and its procurement depends on bureaucratic procedures, as it is controlled by the Brazilian Army. This research to assessed the effect of replacing the ACS KNO3 for a commercially available fertilizer (KNO3- based) on the micropropagation of the prickly pear cactus (Opuntia stricta (Haw.) Haw. cv. Elephant Ear. Treatments used six different fertilizer concentrations (0, 0.5, 1, 1.5, 2 and 2.5 g L-¹) and a control consisting of 1.9 g L-¹ KNO3, as shown in the MS salts. The survival, size and number of sprouts and the value of fresh biomass were evaluated. After seedling acclimation, we assessed the survival, number of sprouts, length, and number of roots, racket formation, average fresh biomass mass, macronutrient absorption and morphological changes of the seedlings. Explants inoculated with fertilizers at concentrations of 0.0; 2.0 and 2.5 g L-¹ did not grow. The response of explants at concentrations of 0.5 and 1.5 g L-¹ of the fertilizer were the same as those developed in a KNO3 medium, and at a concentration of 1.0 g L-¹, in all variables, the means were higher than those of the control medium. Therefore, it showed the feasibility of using fertilizers in the in vitro cultivation of the prickly pear cactus, which may remove bureaucratic barriers and reduce product costs by 99.12%.(AU)

Na micropropagação, o nitrato de potássio (KNO3), reagente puro para análise (P.A.), utilizado no preparo dos meios de cultura, possui custo elevado e a sua aquisição depende de trâmites burocráticos, por se tratar de substância controlada pelo Exército Brasileiro. O objetivo deste trabalho foi avaliar o efeito da substituição do KNO3 P.A. por fertilizante comercial (com fonte de KNO3), encontrado livremente no comércio, na micropropagação de palma (Opuntia stricta (Haw.) Haw. cv Orelha de Elefante. Os tratamentos foram de seis concentrações do fertilizante (0; 0,5; 1; 1,5; 2 e 2,5 g L-¹) e um controle constituído de 1,9 g L-¹ de reagente KNO3, conforme mostrado nos sais MS. Avaliou-se a sobrevivência, tamanho e número de brotações do explante, e o valor da biomassa fresca. Após a aclimatização das mudas avaliou-se a sobrevivência, número de brotações, comprimento da parte aérea, número de raízes, formação da raquete, massa média da biomassa fresca, absorção de macronutrientes e alterações morfológicas das mudas. Os explantes inoculados em meio com fertilizantes nas concentrações de 0,0; 2,0 e 2,5 g L-¹ não se desenvolveram. A resposta dos explantes nas concentrações de 0,5 e 1,5 g L-¹ do fertilizante foram iguais aos desenvolvidos em meio contendo KNO3, e na concentração de 1,0 g L-¹, em todas as variáveis, as médias foram superiores em relação as do controle. Dessa forma, constatou-se a viabilidade do uso do fertilizante no cultivo in vitro da palma, o que propiciou a eliminação dos entraves burocráticos e redução no custo de 99,12% na compra do produto.(AU)

Carbon and water relations for developing fruits of Opuntia ficus-indica (L.) Miller, including effects of drought and gibberellic acid.

Growth, gas exchange rates, and carbohydrate content were studied for developing fruits of the cultivated cactus Opuntia ficus-indica (L.) Miller, including effects of drought and exogenous gibberellic acid (GA3). Fruit development required 110 d from the time of bud differentiation to ripening at 80 d after anthesis, when the fruit mass averaged 67 g. Stomatal conductance and net CO2 uptake rates for fruits were higher during the night; they were maximal at 7 d before anthesis and decreased as development progressed. Fruits undergoing drought, imposed by detaching terminal stems bearing fruits, were 50% smaller than the control at 80 d after anthesis and did not ripen. Fruits injected with 2 ml of 500 ppm GA3 were 30% smaller than the control at 80 d after anthesis; they contained a large proportion of aborted seeds that produced a weak sink signal for dry mass accumulation. Gas exchange was higher at 21 d after anthesis for fruits treated with GA3. Total soluble sugars represented 40% of the fruit's dry mass until 45 d after anthesis, when the sugar content rapidly increased, reaching 90% at 73 d after anthesis. Such an increase was not observed for fruits treated with GA3, and the sugar content for fruits undergoing drought remained low throughout development. Starch content increased for developing fruits of O. ficus-indica until 14 d after anthesis and, except for the fruits undergoing drought, decreased thereafter. Fruit development for O. ficus-indica is apparently regulated by water availability as well as hormonal signals originating both within and outside the fruit.