Opuntia ficus-indica (L.) Mill.: A Multi-Benefit Potential to Be Exploited.

Consumer interest in foods with enhanced nutritional quality has increased in recent years. The nutritional and bioactive characterization of fruits and their byproducts, as well as their use in the formulation of new food products, is advisable, contributing to decrease the global concerns related to food waste and food security. Moreover, the compounds present in these raw materials and the study of their biological properties can promote health and help to prevent some chronic diseases. Opuntia ficus-indica (L.) Mill. (prickly pear) is a plant that grows wild in the arid and semi-arid regions of the world, being a food source for ones and a potential for others, but not properly valued. This paper carries out an exhaustive review of the scientific literature on the nutritional composition and bioactive compounds of prickly pear and its constituents, as well as its main biological activities and applications. It is a good source of dietary fiber, vitamins and bioactive compounds. Many of its natural compounds have interesting biological activities such as anti-inflammatory, hypoglycemic and antimicrobial. The antioxidant power of prickly pear makes it a good candidate as an ingredient of new food products with fascinating properties for health promotion and/or to be used as natural extracts for food, pharmaceutic or cosmetic applications. In addition, it could be a key player in food security in many arid and semi-arid regions of the world, where there are often no more plants.

Relationship between weather conditions and the physicochemical characteristics of cladodes and mucilage from two cactus pear species.

Climate change, limited water resources and expected population increases would require crops which contribute toward more resilient, more productive, more sustainable and climate-smart food systems. The cactus pear is a drought-resistant and sustainable food source to humans and livestock alike. Cactus mucilage has multiple applications in the food and packaging industry. It is eco-friendly, economical, functional and has multiple health benefits. However, the researchers observed umpteen variations in extracted mucilage yield and viscosity every time the cladodes were harvested, making the standardisation of formulations troublesome. We aimed to examine the effect of weather conditions on the physicochemical characteristics of cactus pear cladodes and mucilage extracted over two seasons to understand these observed variations in mucilage characteristics. Forty cladodes, ten from each of Opuntia ficus-indica Algerian, Morado and Gymno-Carpo and Opuntia robusta Robusta were harvested every month from February to August in Bloemfontein, South Africa. Daily weather data were obtained, weight and moisture contents determined on cladodes and yield, viscosity, pH, conductivity and malic acid content determined on extracted mucilage. Pearson correlation coefficients were calculated between the weather conditions, cladode properties, and mucilage properties. Contrary to common belief, neither increasing cladode weight as they grow, nor rainfall were the leading causes of mucilage inconsistencies. However, the correlations showed a relationship between environmental temperatures, cladode pH and conductivity, and mucilage viscosity and yields. In hot summer weather, the pH was lower, which led to an abundance of positive ions in cladodes. The H+ ions neutralise the negative charges along the outstretched mucilage molecule, causing it to coil up, reducing the viscosity of the mucilage. Thus, environmental temperatures rather than rainfall or cladode maturity influenced the physicochemical characteristics of mucilage. The findings should make an essential contribution in predicting the physicochemical characteristics of mucilage for specific food-related functions by observing the weather conditions.

Resilience of cactus pear genotypes in a tropical semi-arid region subject to climatic cultivation restriction.

The cactus pear has demonstrated productive potential in arid and semi-arid regions due to its photosynthetic process of crassulacean acid metabolism. Thus, this study aimed to evaluate agronomic characteristics and chemical composition of three genotypes of cactus pear at different locations of a tropical semiarid region classified as non-suitable for cactus pear cultivation. A completely randomized design in a factorial arrangement (3 × 7) (three genotypes of cactus pear [Miúda, Baiana (Nopalea cochenillifera) and Orelha de Efefante Mexicana - OEM (Opuntia stricta)] and seven locations) was used. The climatic conditions characterized an environment that restricts the growth of cactus pear genotypes, mainly due to the air relative humidity values. All morphological characteristics of the cactus pear genotypes were influenced by the interaction genotype x location, with higher expression of the characteristics on the different genotypes under hot semi-arid climate and tropical wet and dry climate. An effect of the interaction genotype x location was observed (p < 0.05) on water use efficiency, water accumulation and carrying capacity, where the highest values were observed for genotype Baiana at location 1. Also, there was influence of the interaction genotype x location over the chemical composition of the cactus pear. The cultivation of cactus pear is recommended under restricted climatic conditions in semi-arid tropical regions, especially the genotype Baiana, based on growth factors, biomass production and chemical composition.

Physico-chemical changes in cladodes of Opuntia ficus-indica as a function of the growth stage and harvesting areas.

The physicochemical properties of cladodes Opuntia ficus-indica (OFI) vary widely during maturation. However, few studies have been performed to evaluate changes in chemical characteristics on the pad depending on the maturity stages. Chemical proximate analysis like the content of total sugars, protein, dry matter, pH, conductivity and ash, depending on the variation of weight of the pad and the growing region was done to determine the changes of characteristics of nopal. Significant changes in physicochemical properties were observed among harvesting sites and during the growing stages. The principal component analysis was then performed to evaluate the relationship between harvesting sites, growth stages, and physicochemical properties. Results highlighted that Sidi El Aidi can be categorized as a poor ecotype among the studied ecotypes, besides, overall harvesting sites pH and proteins had a significant negative correlation with ash, total sugars, reducing sugars, conductivity proteins decrease with increasing age of nopals while total sugars, reducing sugars, and ash content showed the opposite trend. The high total sugar content, minerals of nopal pad (weight higher than 200 g) and proteins (weight lower than 200 g) could be an interesting source of these important components for human diets and also could be used in food, cosmetics, and pharmaceutical industry.

Comparative development of staminate and pistillate flowers in the dioecious cactus Opuntia robusta.

KEY MESSAGE: PCD role in unisexual flowers. The developmental processes underlying the transition from hermaphroditism to unisexuality are key to understanding variation and evolution of floral structure and function. A detailed examination of the cytological and histological patterns involved in pollen and ovule development of staminate and pistillate flowers in the dioecious Opuntia robusta was undertaken, and the potential involvement of programmed cell death in the abortion of the sex whorls was explored. Flowers initiated development as hermaphrodites and became functionally unisexual by anthesis. Female individuals have pistillate flowers with a conspicuous stigma, functional ovary, collapsed stamens and no pollen grains. Male individuals have staminate flowers, with large yellow anthers, abundant pollen grains, underdeveloped stigma, style and an ovary that rarely produced ovules. In pistillate flowers, anther abortion resulted from the premature degradation of the tapetum by PCD, followed by irregular deposition of callose wall around the microsporocytes, and finally by microspore degradation. In staminate flowers, the stigma could support pollen germination; however, the ovaries were reduced, with evidence of placental arrest and ovule abortion through PCD, when ovules were present. We demonstrate that PCD is recruited in both pistillate and staminate flower development; however, it occurs at different times of floral development. This study contributes to the understanding of the nature of the O. robusta breeding system and identifies developmental landmarks that contribute to sexual determination in Cactaceae.

Morfometria de cladódios de Opuntia stricta sob lâminas de irrigação e adubação orgânica no semiárido paraibano / Morphometry of Opuntia stricta cladodes submitted to different irrigation levels and organic fertilizer in the paraiba semi-arid region / Morfometría de cladodios de Opuntia stricta bajo cuchillas de riego y fertilización orgánica en el semiárido paraibano

A Palma Forrageira é uma planta xerófila de grande importância para a manutenção da pecuária nordestina, sobretudo, durante os períodos de estiagem. No entanto, diante da necessidade da recuperação dos palmais destruídos pela cochonilha do carmim, faz-se necessário conhecer os efeitos das práticas de manejo sobre as novas variedades introduzidas. Nesse sentido, este trabalho objetivou avaliar o efeito de diferentes lâminas de irrigação e fontes de adubação orgânica sobre a morfometria de cladódios da palma forrageira 'Orelha de Elefante Mexicana' (Opuntia stricta [Haw.] Haw.) cultivada no Semiárido. O experimento foi conduzido na Fazenda Riachão, Boa Vista, Paraíba. A área de plantio utilizada estava no segundo ciclo depois de dois anos de implantação. Utilizou-se um fatorial duplo 3 x 6 (tipos de adubação; lâminas de irrigação) em delineamento em blocos casualizados, com cinco repetições. Utilizaram-se dois tipos de esterco, bovino e caprino e a testemunha, associados com a ausência de irrigação e cinco lâminas diferentes (0; 1,5; 2,5; 3,5; 4,5 e 5,5 L de água por semana por planta). Ao fim de três meses, foram mensurados a área do cladódio, índice de área de cladódio e volume de cladódios total. Observou-se efeito significativo a 1% de probabilidade, pelo Teste F, da lâmina de irrigação sob todos os parâmetros analisados, sendo a lâmina de 5,5 L/semana a que propiciou os melhores resultados para a maioria das variáveis. Os tipos de esterco isoladamente não diferiram estatisticamente entre si, no entanto, o esterco caprino associado com a irrigação apresentou melhores resultados.(AU)

The forage palm is a xerophilous crop of great importance for the maintenance of livestock in the Northeast region of Brazil during periods of drought. However, due to the need to recover the palm trees destroyed by the prickly pear cochineal, it is important to know the effects of management practices on the new varieties that have been introduced in the area. In this sense, this study aimed at evaluating the effect of different irrigation levels and sources of organic fertilization on the morphometric attributes of forage palm cladodes of the Erect Prickly Pear (Opuntia stricta [Haw.] Haw.) grown in a semi-arid environment. The experiment was conducted at Fazenda Riachão, in the city of Boa Vista, state of Paraíba. The planting area used was at its second cycle after two years of implantation. Two types of manure ­ cattle and goat, as well as control, associated with absence of irrigation and five different levels of irrigation, ranging from 0; 1.5; 2.5; 3,.5; 4.5 and 5.5 L of water per week per plant were used. A 3 x 6 double factorial model (types of fertilization, irrigation levels) was used in a randomized block design, with five replications. At the end of a three-months' period, the cladode area, cladode area index, and total cladode volume were measured. A significant effect could be observed at 1% probability by F Test regarding the irrigation level for all analyzed parameters, with the 5.5 L/week irrigation mode providing the best results for most of the studied parameters. The manure types alone did not differ statistically from each other; however, the goat manure associated with irrigation presented better results than those for cattle manure.(AU)

La palma forrajera es una planta xerófila de gran importancia para el mantenimiento del ganado del noreste, especialmente durante los períodos de sequía. Sin embargo, en vista de la necesidad de recuperación de las palmas destruidas por la cochinilla carmínica, es necesario conocer los efectos de las prácticas de manejo en las nuevas variedades introducidas. En ese sentido, esta investigación tuvo como objetivo evaluar el efecto de diferentes cuchillas de riego y fuentes de fertilización orgánica en la morfometría de cladodios de la palma forrajera 'Oreja de Elefante Mexicano' (Opuntia stricta [Haw.] Haw.) cultivada en el Semiárido. El experimento se realizó en la Hacienda Riachão, Boa Vista, Paraíba. El área de plantación utilizada estaba en el segundo ciclo después de dos años de implantación. Se usó un factorial doble 3 x 6 (tipos de fertilización; cuchillas de riego) en un diseño de bloques al azar con cinco repeticiones. Se utilizaron dos tipos de estiércol, siendo de ganado y cabras y el control, asociados con la ausencia de riego y cinco diapositivas diferentes (0; 1.5; 2.5; 3.5; 4.5 y 5.5 L de agua por semana por planta). Después de tres meses, se midieron el área del cladodio, el índice del área del cladodio y el volumen total del cladodio. Se observó un efecto significativo con una probabilidad del 1%, mediante la Prueba F, de la cuchilla de riego bajo todos los parámetros analizados, con la cuchilla de 5.5 L/semana proporcionando los mejores resultados para la mayoría de las variables. Los tipos de estiércol por sí solos no difirieron estadísticamente, sin embargo, el estiércol de cabra asociado con el riego presentó mejores resultados.(AU)

Promising Physical, Physicochemical, and Biochemical Background Contained in Peels of Prickly Pear Fruit Growing under Hard Ecological Conditions in the Mediterranean Countries.

BACKGROUND: Prickly pear (Opuntia spp.), called Barbary fig, is a cultivated species springing from family Cactaceae. It is native to Mexico and has been naturalized in other continents, especially the Mediterranean countries (North Africa). The aim of the study was to investigate the physical, physicochemical, and biochemical criteria of peels of three Moroccan prickly pear varieties (Aakria, Derbana, and Mles) growing in the Rhamna regions (dry area). MATERIAL AND METHODS: Both physicochemical characteristics (humidity, water activity, Brix, ash content, pH, and total titratable acidity) and biochemical characteristics (total carotenoid content, betalain content, total polyphenolic content, and ascorbic acid content) were were studied according to previously reported methods. RESULTS: Regarding the physiochemical criteria, the moisture of the fresh peels of studied varieties ranged from 81.59 ± 0.02 to 83.47 ± 0.02%. The water activity (aw) ranged from 0.862 ± 0.001 to 0.872 ± 0.001. The values of Brix varied from 14.69 ± 0.05° Bx to 15.80 ± 0.03° Bx. pH values varied from 5.13 ± 0.01 to 5.32. The total titratable acidity values ranged from 0.130 ± 0.008 to 0.196 ± 0.014 g of citric acid/100 g of FM (fresh matter). The ash content values ranged from 8.92 ± 0.10 to 11.04 ± 0.06 g/100 g of FM. Regarding the biochemical criteria, the total carotenoid content ranged from 2.29 ± 0.01 to 2.87 ± 0.01 µg/g of FM. The total betalain content ranged from 6213.46 ± 58.86 to 8487.19 ± 51.71 µg/100 g of FM. The total polyphenolic content varied from 160 ± 3.55 to 243.79 ± 5.55 mg GA E/100 g of FM. The ascorbic content ranged from 58.21 ± 0.24 to 74.72 ± 0.17 mg/100 g of FM. CONCLUSION: The findings of physicochemical and biochemical criteria of the investigated varieties growing in Moroccan drylands showed promising results in terms of studied parameters.

Effect of irrigation at critical stages on the phenology of flowering and fruiting of the cactus Opuntia spp / Efeito da irrigação em estágios críticos sobre a fenologia de floração e frutificação do cacto Opuntia spp

Abstract This paper briefly reports some effects of irrigations at two critical periods on the phenology of three varieties of cactus pear cultivated in Agadir area: the spineless varieties 'Aissa' and 'Moussa' and the thorny one 'Achefri'. In the first year experiments (2010-2011) treatments of irrigation used were: (T1) 0 mm, (T2) 30 mm during flowering and 30 mm during fruit enlargement and (T3) 30 mm only during fruit enlargement. In the 2nd year experiments, irrigation treatments were: (T1) 0 mm, (T2) 60 mm during flowering and 60 mm during fruit enlargement and (T3) 60 mm only during fruit enlargement. Treatments of irrigation were applied between mid-April and mid-June in the 1st year experiments and in February and May in the 2nd year experiments. Results of the first year experiments showed that the emission of buds was higher in the thorny variety than in the spineless ones (more than 6 emitted buds/cladode vs less than 4.5 in the spineless varieties). In the second year, irrigation increased the emission of buds in the three varieties (more than 7 emitted buds/cladode for each T2 and T3 of all varieties vs not more than 5 for T1) and the duration of the flowering phase of these varieties. However, irrigation did not modify the proportions of fruits reaching commercial maturity during the early or the late period of maturation.

Resumo Este artigo relatou brevemente alguns efeitos das irrigações em dois períodos críticos na fenologia de três variedades de Opuntia cultivadas na área de Agadir: as variedades sem espinhos 'Aissa' e 'Moussa' e um espinhoso 'Achefri'. No primeiro ano (2010-2011) os seguintes tratamentos do experimento da irrigação foram usados: (T1) 0 milímetros, (T2) 30 milímetros durante a florescência e 30 milímetros durante a ampliação do fruto e (T3) 30 milímetros somente durante a ampliação do fruto. No segundo ano das experiências, os tratamentos da irrigação foram: (T1, 0 milímetros), (T2) 60 milímetros durante a florescência e 60 milímetros durante a ampliação do fruto e (T3) 60 milímetros somente durante a ampliação do fruto. Os tratamentos da irrigação foram aplicados entre a metade de abril e metade de junho nas experiências do primeira ano e em fevereiro e maio nas experiências do segundo ano. Os resultados das experiências do primeiro ano mostraram que a emissão de brotos foi maior na variedade espinhosa do que no rufia (mais de 6 emitida gomos/cladode vs inferior a 4,5 no rufia variedades). No segundo ano, a irrigação aumentou a emissão dos botões nas três variedades (mais de 7 botões emitidos/cladÓdio para cada T2 e T3 de todas as variedades não mais que 5 para o T1) e a duração da fase de florescência destas variedades. Contudo, a irrigação não alterou as proporções de frutos que alcançaram a maturidade comercial durante o período adiantado ou atrasado de maturação.

Enhancement of the biogas and biofertilizer production from Opuntia heliabravoana Scheinvar.

Waste Opuntia is an abundant source of biomass to produce biogas and biofertilizer in a small and commercial scale. This crop has a high biomass yield, wide adaptation to diverse climatic zones, rapid growth, and low input requirements. This study aimed to evaluate the combined effect of adjusting C/N ratio and an alkaline pretreatment (AP) of waste Opuntia heliabravoana Scheinvar in the production of biogas and biofertilizer in anaerobic reactors. AP bioreactors produced more biogas than the control (C, without the combined effect of AP); besides, in this process, it was not necessary to use additional water due to the high content of water that is present in the tissue of this crop. On the other hand, both biofertilizers (C and AP) had enssential microbial groups that help to enhance plant nutrition as S-reducers, S-oxidizers, amylolytic, cellulolytic bacteria, anaerobic S-mineralizers, cellulolytic fungi, and P-solubilizers. Also, the AP treatment to help to increase 1.5:1 total nitrogen (TN) concentration decreased the pathogenic microorganisms in the biofertilizer compared to the C treatment. For this reason, Opuntia spp. is a good substrate for production of biogas and biofertilizer with essential nutrients for many crops in area with water scarcity.

Inferring space from time: On the relationship between demography and environmental suitability in the desert plant O. rastrera.

Demographic analyses and ecological niche modeling (ENM) are two popular tools that address species persistence in relation to environmental conditions. Classic demography provides detailed information about the mechanisms that allow a population to grow or remain stable at a local scale, while ENM infers distributions from conditions suitable for species persistence at geographic scales by relating species' occurrences with environmental variables. By integrating these two tools, we may better understand population processes that determine species persistence at a geographic scale. To test this idea, we developed a model that relates climate to demography of the cactus Opuntia rastrera using 15 years of data from one locality. Using this model we determined the geographic area where populations would have positive growth rates given its climatic conditions. The climate-dependent demographic model showed poor performance as a distribution model, but it was helpful in defining some mechanisms that determine species' distributions. For instance, high rainfall had a negative impact on the population growth rate by increasing mortality. Rainy areas to the west of the distribution of O. rastrera were identified as unsuitable both by our climate-dependent demographic model and by a popular ENM algorithm (MaxEnt), suggesting that distribution is constrained by excessive rains due to high mortality. Areas projected to be climatically suitable by MaxEnt were not related with higher population growth rates. Instead, we found a strong correlation between environmental distance to the niche centroid (center of the niche hypervolume, where optimal conditions may occur) and population growth rate, meaning that the niche centroid approach is helpful in finding high-fitness areas.

Phytochemical characterization of different prickly pear (Opuntia ficus-indica (L.) Mill.) cultivars and botanical parts: UHPLC-ESI-MSn metabolomics profiles and their chemometric analysis.

Prickly pear is an important source of bioactive compounds. However, a comprehensive characterization of the phytochemical profile of its aerial botanical parts, considering genotypic differences, has not been conducted. This study evaluated the phytochemical composition of four botanical parts (fruit pulp and skin, and young and adult cladodes) of six cultivars. Analysis was carried out by using two non-targeted UHPLC-ESI-MSn experimental conditions and assisted with multivariate analysis to facilitate data interpretation. Up to 41 compounds, mainly (poly)phenolic molecules, were identified and quantified, 23 compounds being reported for the first time in Opuntia ficus-indica. Phenolic composition varied significantly depending on the part of the plant. Betalains were detected only in the fruit of a red cultivar. This study provided novel insights in terms of identification of bioactives and thorough characterization of botanical parts of prickly pears. This information may be used for the development of prickly pear-derived products with high levels of bioactive compounds.

Opposite Effect of Opuntia ficus-indica L. Juice Depending on Fruit Maturity Stage on Gastrointestinal Physiological Parameters in Rat.

The phytochemical composition and the effect of the green and ripe Opuntia ficus-indica juice on some gastrointestinal (GI) physiological parameters such as stomach emptying and small-intestinal motility and permeability were determined in rats administered multiple concentrations of the prickly pear juice (5, 10, and 20 mL kg-1, b.w., p.o.). Other separate groups of rats were received, respectively; sodium chloride (0.9%, b.w., p.o.), clonidine (α-2-adrenergic agonist, 1 mg kg-1, b.w., i.p.), yohimbine (α-2-adrenergic antagonist, 2 mg kg-1, b.w., i.p.), and loperamide (5 mg kg-1, b.w., p.o.). In vivo reverse effect of juice on GI physiological parameters was investigated using a charcoal meal test, phenol-red colorimetric method, loperamide-induced acute constipation, and castor oil-caused small-bowel hypersecretion. However, the opposite in vitro influence of juice on intestinal permeability homeostasis was assessed by the Ussing chamber system. Mature prickly pear juice administration stimulated significantly and dose dependently the GI transit (GIT; 8-26%) and gastric emptying (0.9-11%) in a rat model. Conversely, the immature prickly pear juice reduced gastric emptying (7-23%), GIT (10-28%), and diarrhea (59-88%). Moreover, the standard drugs have produced their antagonistic effects on GI physiological functions. The permeability of the isolated perfused rat small-intestine has a paradoxical response flowing prickly pear juices administration at diverse doses and maturity grade. Most importantly, the quantitative phytochemical analyses of both juices showed a different composition depending on the degree of maturity. In conclusion, the prickly pear juice at two distinct phases of maturity has different phytochemical characteristics and opposite effects on GI physiological actions in rat.

Effect of irrigation at critical stages on the phenology of flowering and fruiting of the cactus Opuntia spp.

This paper briefly reports some effects of irrigations at two critical periods on the phenology of three varieties of cactus pear cultivated in Agadir area: the spineless varieties 'Aissa' and 'Moussa' and the thorny one 'Achefri'. In the first year experiments (2010-2011) treatments of irrigation used were: (T1) 0 mm, (T2) 30 mm during flowering and 30 mm during fruit enlargement and (T3) 30 mm only during fruit enlargement. In the 2nd year experiments, irrigation treatments were: (T1) 0 mm, (T2) 60 mm during flowering and 60 mm during fruit enlargement and (T3) 60 mm only during fruit enlargement. Treatments of irrigation were applied between mid-April and mid-June in the 1st year experiments and in February and May in the 2nd year experiments. Results of the first year experiments showed that the emission of buds was higher in the thorny variety than in the spineless ones (more than 6 emitted buds/cladode vs less than 4.5 in the spineless varieties). In the second year, irrigation increased the emission of buds in the three varieties (more than 7 emitted buds/cladode for each T2 and T3 of all varieties vs not more than 5 for T1) and the duration of the flowering phase of these varieties. However, irrigation did not modify the proportions of fruits reaching commercial maturity during the early or the late period of maturation.

Bioactivity, proximate, mineral and volatile profiles along the flowering stages of Opuntia microdasys (Lehm.): defining potential applications.

Opuntia spp. flowers have been traditionally used for medical purposes, mostly because of their diversity in bioactive molecules with health promoting properties. The proximate, mineral and volatile compound profiles, together with the cytotoxic and antimicrobial properties were characterized in O. microdasys flowers at different maturity stages, revealing several statistically significant differences. O. microdasys stood out mainly for its high contents of dietary fiber, potassium and camphor, and its high activities against HCT15 cells, Staphylococcus aureus, Aspergillus versicolor and Penicillium funiculosum. The vegetative stage showed the highest cytotoxic and antifungal activities, whilst the full flowering stage was particularly active against bacterial species. The complete dataset has been classified by principal component analysis, achieving clearly identifiable groups for each flowering stage, elucidating also the most distinctive features, and comprehensively profiling each of the assayed stages. The results might be useful to define the best flowering stage considering practical application purposes.

Characterization of crystalline structures in Opuntia ficus-indica.

This research studies the crystalline compounds present in nopal (Opuntia ficus-indica) cladodes. The identification of the crystalline structures was performed using X-ray diffraction, scanning electron microscopy, mass spectrometry, and Fourier transform infrared spectroscopy. The crystalline structures identified were calcium carbonate (calcite) [CaCO3], calcium-magnesium bicarbonate [CaMg(CO3)2], magnesium oxide [MgO], calcium oxalate monohydrate [Ca(C2O4)•(H2O)], potassium peroxydiphosphate [K4P2O8] and potassium chloride [KCl]. The SEM images indicate that calcite crystals grow to dipyramidal, octahedral-like, prismatic, and flower-like structures; meanwhile, calcium-magnesium bicarbonate structures show rhombohedral exfoliation and calcium oxalate monohydrate is present in a drusenoid morphology. These calcium carbonate compounds have a great importance for humans because their bioavailability. This is the first report about the identification and structural analysis of calcium carbonate and calcium-magnesium bicarbonate in nopal cladodes, as well as the presence of magnesium oxide, potassium peroxydiphosphate and potassium chloride in these plants. The significance of the study of the inorganic components of these cactus plants is related with the increasing interest in the potential use of Opuntia as a raw material of products for the food, pharmaceutical, and cosmetic industries.

Functional and hypoglycemic properties of nopal cladodes (O. ficus-indica) at different maturity stages using in vitro and in vivo tests.

Nopal (Opuntia ficus-indica) cladodes are recommended for their therapeutic properties; their maturity stage may affect their biological properties. Cladodes of three maturity stages, from the same crop and location, were dehydrated and evaluated for some of their physicochemical and nutritional characteristics and antidiabetic properties. The flours of small and medium cladodes (SCF and MCF, respectively) had higher contents of dietary fiber, water absorption, swelling, and viscosity compared to those of the large cladode flour (LCF). Streptozotocin-induced diabetic rats, treated with MCF and SCF (doses of 50 mg/kg body weight), showed reduction of postprandial blood glucose on 46.0 and 23.6%, respectively (p < 0.05), in relation to the control; and LCF had no significant effect. In vitro, glucose diffusion tests showed similar ranking by the two former samples, whereas the latter was close to the control. Cladode maturity stages showed different fiber content and produced suspensions with differences in viscosity, which may affect in vitro and in vivo glucose responses.

Programmed cell death promotes male sterility in the functional dioecious Opuntia stenopetala (Cactaceae).

BACKGROUND AND AIMS: The sexual separation in dioecious species has interested biologists for decades; however, the cellular mechanism leading to unisexuality has been poorly understood. In this study, the cellular changes that lead to male sterility in the functionally dioecious cactus, Opuntia stenopetala, are described. METHODS: The spatial and temporal patterns of programmed cell death (PCD) were determined in the anthers of male and female flowers using scanning electron microscopy analysis and histological observations, focusing attention on the transition from bisexual to unisexual development. In addition, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling assays were used as an indicator of DNA fragmentation to corroborate PCD. KEY RESULTS: PCD was detected in anthers of both female and male flowers, but their patterns differed in time and space. Functionally male individuals developed viable pollen, and normal development involved PCD on each layer of the anther wall, which occurred progressively from the inner (tapetum) to the outer layer (epidermis). Conversely, functional female individuals aborted anthers by premature and displaced PCD. In anthers of female flowers, the first signs of PCD, such as a nucleus with irregular shape, fragmented and condensed chromatin, high vacuolization and condensed cytoplasm, occurred at the microspore mother cell stage. Later these features were observed simultaneously in all anther wall layers, connective tissue and filament. Neither pollen formation nor anther dehiscence was detected in female flowers of O. stenopetala due to total anther disruption. CONCLUSIONS: Temporal and spatial changes in the patterns of PCD are responsible for male sterility of female flowers in O. stenopetala. Male fertility requires the co-ordination of different events, which, when altered, can lead to male sterility and to functionally unisexual individuals. PCD could be a widespread mechanism in the determination of functionally dioecious species.

Betacyanin and other antioxidants production during growth of Opuntia stricta (Haw.) fruits.

Mature cactus pears from Opuntia stricta have a dark purple color due to high betacyanin concentration, whose biosynthesis is initiated with the amino acid L-tyrosine as a primary precursor. This study followed the maturation and ripening processes of Opuntia stricta fruits to harvest them at high betacyanin and other antioxidant concentrations. Fruits lasted 9 months for final ripening. Physical and compositional changes at different maturation and ripening stages have been determined. Thus, ripe fruits were around 4.72 ± 0.10 cm length, 2.94 ± 0.05 cm diameter and 22.71 ± 0.20 g weight; moisture and pH were maintained at 87.05 ± 0.19 % and 3.37 ± 0.12, respectively. Purple pigment production started in the ovary of immature fruits four months after anthesis (MAA). Concentration of all analyzed metabolites increased from immature (4 MAA) until ripe (9 MAA) stage. In ripe fruits, reducing sugars were 4.72 ± 0.54 g/100 g ff and total phenols 135.17 ± 0.68 mg gallic acid/100 g ff. Metabolites identified by HPLC were the betacyanins: betanin (60.17 ± 1.08 mg/100 g ff), isobetanin (7.58 ± 0.94 mg/100 g ff) and betanidin (13.48 ± 0.87 mg/100 g ff). Also, L-ascorbic acid (35.03 ± 1.06 mg/100 g ff) and L-tyrosine (4.43 ± 0.73 mg/100 g ff) were determined. Furthermore, the addition of L-tyrosine or L-dopa to fruit pulp of moderately ripe fruits, increased betacyanin concentrations 17 (103.3 ± 3.8 mg/100 g) and 32 % (114.3 ± 4.1 mg/100 g), respectively.

Inception of maleness: auxin contribution to flower masculinization in the dioecious cactus Opuntia stenopetala.

In Opuntia stenopetala, flowers initiate as hermaphrodite; however, at maturity, only the stamens in male flowers and the gynoecium in female flowers become functional. At early developmental stages, growth and morphogenesis of the gynoecium in male flowers cease, forming a short style lacking stigmatic tissue at maturity. Here, an analysis of the masculinization process of this species and its relationship with auxin metabolism during gynoecium morphogenesis is presented. Histological analysis and scanning electron microscopy were performed; auxin levels were immunoanalyzed and exogenous auxin was applied to developing gynoecia. Male flower style-tissue patterning revealed morphological defects in the vascular bundles, stylar canal, and transmitting tissue. These features are similar to those observed in Arabidopsis thaliana mutant plants affected in auxin transport, metabolism, or signaling. Notably, when comparing auxin levels between male and female gynoecia from O. stenopetala at an early developmental stage, we found that they were particularly low in the male gynoecium. Consequently, exogenous auxin application on male gynoecia partially restored the defects of gynoecium development. We therefore hypothesize that, the arrest in male flower gynoecia patterning could be related to altered auxin homeostasis; alternatively, the addition of auxin could compensate for the lack of another unknown factor affecting male flower gynoecium development.

Conserved and divergent rhythms of crassulacean acid metabolism-related and core clock gene expression in the cactus Opuntia ficus-indica.

The cactus Opuntia ficus-indica is a constitutive Crassulacean acid metabolism (CAM) species. Current knowledge of CAM metabolism suggests that the enzyme phosphoenolpyruvate carboxylase kinase (PPCK) is circadian regulated at the transcriptional level, whereas phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (MDH), NADP-malic enzyme (NADP-ME), and pyruvate phosphate dikinase (PPDK) are posttranslationally controlled. As little transcriptomic data are available from obligate CAM plants, we created an expressed sequence tag database derived from different organs and developmental stages. Sequences were assembled, compared with sequences in the National Center for Biotechnology Information nonredundant database for identification of putative orthologs, and mapped using Kyoto Encyclopedia of Genes and Genomes Orthology and Gene Ontology. We identified genes involved in circadian regulation and CAM metabolism for transcriptomic analysis in plants grown in long days. We identified stable reference genes for quantitative polymerase chain reaction and found that OfiSAND, like its counterpart in Arabidopsis (Arabidopsis thaliana), and OfiTUB are generally appropriate standards for use in the quantification of gene expression in O. ficus-indica. Three kinds of expression profiles were found: transcripts of OfiPPCK oscillated with a 24-h periodicity; transcripts of the light-active OfiNADP-ME and OfiPPDK genes adapted to 12-h cycles, while transcript accumulation patterns of OfiPEPC and OfiMDH were arrhythmic. Expression of the circadian clock gene OfiTOC1, similar to Arabidopsis, oscillated with a 24-h periodicity, peaking at night. Expression of OfiCCA1 and OfiPRR9, unlike in Arabidopsis, adapted best to a 12-h rhythm, suggesting that circadian clock gene interactions differ from those of Arabidopsis. Our results indicate that the evolution of CAM metabolism could be the result of modified circadian regulation at both the transcriptional and posttranscriptional levels.