Ziziphus Joazeiro Research Articles

Pollen diversity in honey from Sergipe, Brazil

The pollen contents of honeys from 22 different municipalities of the Brazilian state of Sergipe were analysed. A total of 90 pollen types distributed in 32 plant families were identified. Fabaceae had the highest representation in number of pollen types (29 types), followed by Asteraceae (eight types), Rubiaceae (seven types), Anacardiaceae and Malvaceae (four each) and Euphorbiaceae and Myrtaceae (three each). The presence of dominant pollen was detected in 14 samples, with the dominant types Mimosa pudica in five samples, Alternanthera in two samples, Angelonia, Cocos nucifera, Mimosa arenosa, Mimosa tenuiflora, Myrcia, Prosopis juliflora, Protium and Schinus in one sample each. Eleven pollen types were recorded as accessory pollen: Borreria verticillata, Mimosa pudica, Tapira in three samples, Mitracarpus hirtus in two samples, Angelonia, Baccharis, Cocos nucifera, Melastomataceae, Protium, Salvia and Senna macranthera in one sample each. Pollen types from the genus Mimosa were prominent in the samples indicating the important contribution of species with palynological affinities with the pollen types found in this genus in the apicultural production of the region. Pollen types from species endemic to the Caatinga were found in the pollen spectrum for Sergipe: Mimosa adenophylla, Mimosa ophthalmocentrica, Mimosa setuligera and Mimosa xiquexiquensis from Fabaceae, and Ziziphus joazeiro from Rhaminaceae.

Application of foam column as green technology for concentration of saponins from sisal (Agave sisalana) and Juá (Ziziphus joazeiro)

Saponins, molecules classified as triterpenic or steroidal glycosides, are metabolites distributed in all the plant kingdom that can be used for the production of foods, cosmetics, and pharmaceuticals, as well as in soil bioremediation. Saponins are normally extracted from natural resources with water, ethanol and/or methanol, and then concentrated by liquid-liquid partitioning with n-butanol. An alternative concentration method is with a foam column, by which the saponins can be concentrated via preferential adsorption at a gas-liquid interface. Therefore, the objective of this work was the use of a foam column for the concentration of saponins from juá and sisal, evaluating parameters such as: initial working volume in the column, saponin concentration in the extracts from juá and sisal, air flow rate, pH, Raschig rings loading and operation time. When a gradient air flow rate and 25 g of Raschig rings were used, 82.6% of the jua saponins loaded onto the system were recovered in a 3.46-fold concentrated solution after 9 h of operation. Regarding sisal saponins, a concentration factor of 1.98 was observed with 90.5% of saponin recovery during 4.5 h of operation.

Pollen grains in honeys produced by Tetragonisca angustula (Latreille, 1811) (Hymenoptera: Apidae) in tropical semi-arid areas of north-eastern Brazil

The flora of north-eastern Brazil offers a source of nectariferous–polliniferous species that support many native pollinators. However, few studies have examined the plant–Meliponini interaction, especially from the melissopalynological aspect. We assessed the flora exploited by Tetragonisca angustula in two caatinga (dry vegetation) areas in the Brazilian semi-arid region through pollen analysis of honeys with the goal of answering the following questions: (a) What are the most representative pollens found in the honeys? (b) Do certain pollen types function as regional geographic markers? (c) What are the characteristics of the trophic niche of T. angustula in these areas? The honeys (n = 27) were collected every month from October 2010 to December 2011 in Itaberaba and Ruy Barbosa, diluted in tepid water and 95 % ethanol and subsequently acetolysed. The results revealed 67 pollen types in the honeys, with 25 common to both study areas and most of them belonging to the family Fabaceae (>10 types). The most frequent pollen types were Heteropterys, Mikania, Myrcia, Prosopis juliflora and Solanum for Itaberaba and Heteropterys, Mimosa tenuiflora, P. juliflora, Schinus, Senna macranthera, Solanum and Syagrus coronata for Ruy Barbosa. Anadenanthera colubrina, Poincianella pyramidalis and Ziziphus joazeiro were considered markers for caatinga flora. The amplitude of the trophic niche varied between 0.36 and 2.55, while the evenness ranged from 0.15 to 0.77, characterising the foraging habit of T. angustula as polylectic with a more homogeneous use of the flora in Ruy Barbosa than in Itaberaba.

Recovery of Saponins from Jua (Ziziphus joazeiro) by Micellar Extraction and Cloud Point Preconcentration

AbstractJuá (Ziziphus joazeiro) is a Brazilian plant and its bark has been used as a detergent and phytotherapic due to its high saponin content (2–10 %). Saponins are triterpenic glycosides with some properties that aid their use in food, cosmetic and pharmaceutical industries. The object of the present work was to develop an extraction and concentration process of saponins from jua bark, using green solvents such as water and ethanol. Firstly, the extraction conditions optimization was carried out using a central composite design, and compared with other methods such as Soxhlet, ultrasound‐assisted extraction and micellar extraction. Then, cloud point preconcentration was tested to select the salt type and its concentration which promotes a higher concentration factor and partition coefficient at room temperature. Finally, the removal of a t‐octyl phenol ethoxylate (9–10 EO) nonionic surfactant by adsorption was evaluated by optimizing the adsorbent type and its concentration, temperature and time of adsorption, in addition to the adsorbent recycling. Orbital shaker extraction leads to a recovery of 45.6 % saponins under the following conditions: temperature, 38.8 °C; jua/solvent ratio, 0.272; stirring speed, 300 rpm; extraction time, 2 h. Under these conditions, saponins recovery reached 90.8 % when using 15 % v/v of the nonionic surfactant, and a preconcentration factor of 14.2 was obtained by adding sodium carbonate 20 % w/v. The preconcentration factor decreased to a value of 10.1, after nonionic surfactant removal by a hydrophobic crosslinked polystyrene copolymer resin.

Functional properties of saponins from sisal (Agave sisalana) and juá (Ziziphus joazeiro): Critical micellar concentration, antioxidant and antimicrobial activities

Saponins are triterpenic or steroidal glycosides largely distributed in plant kingdom, which have many physicochemical (foaming, emulsification, solubilization, sweetness, bitterness) and biological properties (haemolytic, antimicrobial, antioxidant, moluscacide, insecticide, ichthyocide), which are exploited in many applications in food, cosmetics and pharmaceuticals industries, and also in soil bioremediation. Among the saponins properties, critical micellar concentration (CMC), maximum surface density and aggregation number (number of monomers in a micelle) are of great importance for application as surfactants and foaming agents. These are influenced by variables such as temperature, salt concentration, aqueous phase pH, solvent concentration and type (ethanol, methanol). The objective of this work was to evaluate some functional properties as critical micellar concentration (CMC), antimicrobial and antioxidant activities of two different saponins originated from Brazilian agrobiodiversity: sisal (Agave sisalana), with steroidal aglycone, and juá (Ziziphus joazeiro), a triterpenic aglycone. The variation of CMC from juá and sisal saponins was measured against parameters as temperature, pH and NaCl (%m/v) concentration, using turbidimetric titration (spectrophotometry), and for each CMC, it was detected the respective surface tension. The highest reduction on CMC values from juá saponins can be observed in neutral pH, near room temperature (25–30°C) and saline concentrations among 2 and 4% m/v, while for sisal saponins, the conditions were pH between 3 and 4 with near room temperature; or pH among 10–11 with temperatures around 55–60°C; and saline concentration from 2 to 6% m/v. Antioxidant activity of isolated saponins from juá and sisal was very low, represented only 25% of the antioxidant activity reached by its corresponding raw extracts (saponins and phenolics). Juá saponins presented antifungal activity against Candida albicans (156μg/mL) and Aspergillus niger (312.5μg/mL), while sisal saponins possessed no antimicrobial activity.

Extraction of saponins from sisal (Agave sisalana) and juá (Ziziphus joazeiro) with cholinium-based ionic liquids and deep eutectic solvents

Saponins are triterpenic or steroidal glycosides present in many plants, as jua (Ziziphus joazeiro) and sisal (Agave sisalana), representatives of the Brazilian agrobiodiversity. Due to their properties, saponins are finding application in fine chemistry and pharmaceutical industry. Thus, the study of the extraction of these components from their natural matrixes and their optimization is of interest. The objective of this work is to evaluate the performance of the extraction of saponins from jua and sisal, using cholinium salts and deep eutectic solvents (DES) as adjuvants to aqueous and hydroalcoholic solutions. The goal is to simultaneously optimize the saponin extraction efficiency and the selectivity between saponins and phenolic compounds from these two plant matrixes. For this purpose, 13 cholinium-based ionic liquids and salts and 9 DES were used as adjuvants. It was observed that DES performed better in the proposed extractions and the optimal extraction mixture composition was determined using a mixture-design statistic method. Using this information, other experimental parameters, such as extraction time, raw material/solvent ratio and temperature were also evaluated and optimized. In the end, we show that it is possible to increase the extraction efficiency and selectivity of saponins from jua in 170 % and 18.39 and for sisal 245 % and 10.34, respectively, by the addition of a selected DES.

Parasitismo natural em moscas-das-frutas (Diptera: Tephritidae) no semiárido do sudoeste da Bahia, Brasil

Parasitoides são importantes agentes de controle natural de tefritídeos, e os conhecimentos sobre as relações tritróficas podem subsidiar o manejo destas pragas. Este trabalho objetivou estimar índices de parasitismo em moscas-das-frutas, em 21 espécies vegetais, e identificar as espécies de parasitoides associados, nas condições do semiárido do sudoeste da Bahia. Oito hospedeiros apresentaram infestação por Anastrepha spp. e, destes, em quatro, ocorreu parasitismo superior a 20,0%, sendo: 20,8% (Ziziphus joazeiro L.); 21,3% (Spondias tuberosa L.); 32,4% (Spondias purpurea L.) e 57,1% (Malpighia emarginata L.). Os parasitoides coletados pertencem à família Braconidae, sendo 89% de Doryctobracon areolatus e 11% de Asobara anastrephae.

Seeds Collected from Different Ziziphus joazeiro Plants Are Differently Affected by Gibberellic Acid

Ziziphus joazeiro is a tree endemic to Caatinga, Northeastern Brazil, with great economic potential. However, its commercial production is still limited due to low and non-uniform germination of seeds. Recently we demonstrated that gibberellic acid (GA3) stimulates the emergence and uniformity of seedlings in this species. In its natural habitat, however, great morphological diversity between Z. joazeiro trees is found, suggesting great genetic variability. Therefore, it was necessary to test if the GA3 effect is a general response. We collected seeds from four plants maintained in a collection. The plants were selected according to contrasting morphological characteristics. After breaking impermeability with 98% sulfuric acid, the seeds were treated with 2 mmol L−1 GA3 or a control with distillated water for 24 h. Effects ranged from great, low, and no effect of GA3 stimulating the percentage and rapidity of emergence between genotypes tested. For reforestation, thus, the GA3 treatment of Z. joazeiro seeds might reduce its genetic variability; but for economic production, it will be an adequate and simple treatment to increase the quantity and uniformity of seedlings.

Hymenopteran Parasitoids Associated With Frugivorous Larvae in a Brazilian Caatinga-Cerrado Ecotone

The purpose of this study was to investigate native species of parasitoids of frugivorous larvae and their associations with host plants in commercial guava orchards and in typical native dry forests of a caatinga-cerrado ecotone in the State of Minas Gerais, Brazil. Nine species of parasitoids were associated with larvae of Anastrepha (Tephritidae) and Neosilba (Lonchaeidae) in fruit of Psidium guajava L. (Myrtaceae), Ziziphus joazeiro Mart. (Rhamnaceae), Spondias tuberosa Arruda (Anacardiaceae), Spondias dulcis Forst. (Anacardiaceae), Syzygium cumini (L.) Skeels (Myrtaceae), and Randia armata (Sw.) DC. (Rubiaceae). Doryctobracon areolatus was the most abundant species, obtained from puparia of Anastrepha zenildae, An. sororcula, An. fraterculus, An. obliqua, and An. turpiniae. This is the first report of Asobara obliqua in Brazil and of As. anastrephae and Tropideucoila weldi in dry forests of Minas Gerais State. The number of species of parasitoids was higher in areas with greater diversity of cultivated species and lower pesticide use. The forest fragments adjacent to the orchards served as shelter for parasitoids of frugivorous larvae.

Atividade alelopática de extrato de sementes de juazeiro

Alelopatia é a liberação de substâncias vegetais inibidoras ou estimulantes no ambiente, podendo estar presente nas sementes de algumas espécies. O objetivo neste trabalho foi avaliar o potencial alelopático do extrato de sementes de juazeiro (Ziziphus joazeiro Mart.) na germinação de sementes de alface (Lactuca sativa L). O experimento foi conduzido em delineamento inteiramente casualizado com quatro repetições e cinco tratamentos (0, 25, 50, 75 e 100% de concentração do extrato bruto). O extrato bruto foi obtido após a extração de 50 g de sementes e agitação em liquidificador com 500 mL de água. Os resultados mostraram efeito alelopático do extrato dependendo da concentração. As maiores concentrações do extrato de sementes de juazeiro afetaram a percentagem e velocidade de germinação e as menores proporcionaram plântulas anormais. Portanto, o extrato apresentou efeito alelopático desfavorável à germinação de sementes de alface.

Chemical characterization of native wild plants of dry seasonal forests of the semi-arid region of northeastern Brazil

The present study seeks to increase the knowledge of the chemical and nutritional characteristics of the species in the Caatinga (semi-arid region from northeastern Brazil) and quantify total anthocyanins, flavonols and carotenoids that are in the native food resources. Nine species were selected from ethnobotanical survey conducted in two rural communities in northeastern Brazil. The study revealed the potential of various food plants in the Caatinga, especially in comparison to other wild species of the same genus that have been investigated in other studies. The following species are of interest for future studies on bioactive substances: Eugenia sp. and Sideroxylon obtusifolium. It is interesting to investigate the potential agroindustry of the latter species, along with Syagrus cearensis and Ziziphus joazeiro. Nevertheless, the most immediate impact of this study may be to improve the populations' use of species such as S. cearensis, S. obtusifolium, and Eugenia sp., which have elevated nutritional potential and could be used in programs to improve the quality of food among the rural population.

Medicinal plants with bioprospecting potential used in semi-arid northeastern Brazil

Objectives Many species of the Caatinga flora are used as medicines in local communities. In recent decades, the knowledge and use of these species has been expanding within this region. We attempted to record the local diversity of medicinal plants used to treat various diseases in a rural community in the state of Ceará, Brazil, and to evaluate the promising medicinal species for bioprospecting studies. Methods An ethnobotanical survey was conducted using free list and semi-structured interviews. To indicate medicinal plants that stood out, the relative importance (RI) of species mentioned by key-informants (20), by general informants in the community (71) and by all informants (91), was analyzed. The group of species that stood out for human body systems based on the informant consensus factor (ICF) was also evaluated. Results A total of 119 species were recorded that were associated with 92 health problems. Of these species, 100 were cited by key-informants and 86 were cited by general informants. Nineteen species showed a great versatility of use, including the following: Myracrodruon urundeuva Allemão, Bauhinia cheilanta (Bong.) Steud., Hymenaea courbaril L., Mentha x villosa Huds ., Ziziphus joazeiro Mart., and Ruta graveolens L . Key-informants cited 33 exclusive species, from which nine presented greater relative importance. General informants cited 19 exclusive species, 2 with greatest relative importance. The therapeutic properties were grouped into 16 body system categories. These grouping categories included skin diseases and diseases of the subcutaneous tissue; sensory system (ears) disorders; respiratory disorders; and injuries, poisoning and other external symptoms. Conclusion The great diversity of medicinal plants used in the community is evident. Some species had both high relative importance and high consensus factors among the informants; these particular species are recommended for bioprospecting studies.

Bee pollen loads and their use in indicating flowering in the Caatinga region of Brazil

The study presents a map of pollen samples collected by Apis mellifera L. in an area of Caatinga (dryland) vegetation in Canudos, Bahia State, Brazil. A total of 62 bee pollen samples obtained from pollen-traps between March/2004 and February/2006 were examined. The pollen loads were acetolyzed and the pollen types identified and counted by sampling using an optical microscope. Thirty-six plant families were found to contribute to the composition of the pollen spectrum of the samples, with 85 different pollen types. Fabaceae was the most represented family (21 pollen types), and Mimosa filipes was the single most frequently observed pollen type (37 samples). The predominant pollen class included 14 pollen types; the secondary class, 18 types; important minor class, 37 types; minor class, 38 types; and 37 “present” pollen types (<1%). Plant species characteristic of the Caatinga region that have apicultural potential, such as Croton spp., Spondias tuberosa Arruda and Ziziphus joazeiro Mart., were well represented in the pollen spectrum. The pollen map was found to be useful for indicating the flowering periods of certain Caatinga species if long and continuous observations were made.

Pollen analysis of honeys from Caatinga vegetation of the state of Bahia, Brazil

Based on pollen analysis, 17 honey samples collected in the Caatinga area from Nova Soure city were classified by botanical origin to identify the most important floral sources. Most of the honey samples were obtained in August and September. A total of 73 pollen types were identified belonging to 30 families, 64 genera and 30 species. The families best represented by their number of pollen types were Mimosaceae (11), Caesalpiniaceae (9), Rubiaceae and Fabaceae (5 each). Predominant pollen types were: Mimosa arenosa in four samples, M. sensitiva and M. tenuiflora in one sample. Pollen from Mimosa ursina was registered for the first time in the pollen spectrum of the Caatinga vegetation. The correspondence analysis showed a similarity among the honey samples based on pollen composition. The high representation of pollen from native species such as Chamaecrista nictitans, C. ramosa, C. swainsonii and Copaifera martii (Caesalpiniaceae); Aeschynomene martii and Zornia sericea (Fabaceae); Herissantia tiubae (Malvaceae); Mimosa arenosa, M. quadrivalvis, M. sensitiva, M. tenuiflora, M. ursina, Piptadenia moniliformis and Plathymenia reticulata (Mimosaceae), and Ziziphus joazeiro (Rhamnaceae) supports the origin of these honeys from Caatinga vegetation.

Alelopatia em extratos de frutos de juazeiro (Ziziphus joazeiro Mart. - Rhamnaceae)

O objetivo deste trabalho foi avaliar o potencial alelopático do extrato de frutos de juazeiro (Ziziphus joazeiro Mart.) sobre as sementes de alface (Lactuca sativa). O experimento foi conduzido em delineamento inteiramente casualizado com 4 repetições e cinco tratamentos (0%, 25%, 50%, 75% e 100% de concentração do extrato bruto). O extrato bruto foi obtido após a extração manual da polpa do fruto e agitação com água em liquidificador utilizando-se 50g de polpa para 500ml de água, e o mesmo foi feito com a casca do fruto. Os resultados mostraram efeito do extrato dependendo da concentração. As maiores concentrações do extrato (100%, 75% e 50%) da polpa dos frutos Z. joazeiro apresentaram efeito alelopático desfavorável sobre a germinação de alface, reduzindo-a em 100%, 98,75% e 82,5% respectivamente. O extrato das cascas dos frutos nas concentrações de 75% e 100% reduziu a germinação da alface em 28,75% e 78,75%.

Intoxicações por plantas em ruminantes e equídeos no Sertão Paraibano

Foi realizado um levantamento das intoxicações por plantas em 20 municípios do Sertão Paraibano, onde foram entrevistados 50 produtores e 11 médicos veterinários. De acordo com o levantamento realizado, Ipomoea asarifolia e Mascagnia rigida são as intoxicações mais importantes. Indigofera suffruticosa, as plantas cianogênicas (Sorghum vulgare, Piptadenia macrocarpa e Manihot spp.), Mimosa tenuiflora, Aspidosperma pyrifolium e Crotalaria retusa são plantas importantes como causa de intoxicações na região. Os entrevistados relataram casos esporádicos de intoxicação por Ricinus communis, Enterolobium contortisiliquum, Prosopis juliflorae Brachiaria decumbens. Ziziphus joazeiro, Passiflora sp., Caesalpina ferrea e Crescentia cujete foram mencionadas como causa de abortos em ruminantes. Frutos de Crescentia cujete foram administrados a duas cabras prenhes causando mortalidade perinatal e abortos. As cascas de feijão (Phaseolus vulgaris e Vigna unguiculata) e as folhas de Licania rigida (oiticica) são associadas à sobrecarga ruminal em bovinos. As frutas de Mangifera indica (manga)e Anacardium occidentale (cajú) são responsabilizadas por causarem intoxicação etílica. Dalechampia sp. e Croton sp. foram citadas pelos entrevistados como possíveis plantas tóxicas, que ainda não tiveram sua toxicidade comprovada.

In vitro antioxidant potential of medicinal plant extracts and their activities against oral bacteria based on Brazilian folk medicine

This study aims to determine antibacterial activities of Cocos nucifera (husk fiber), Ziziphus joazeiro (inner bark), Caesalpinia pyramidalis (leaves), aqueous extracts and Aristolochia cymbifera (rhizomes) alcoholic extract against Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans and Lactobacillus casei. The antioxidant activity and acute toxicity of these extracts were also evaluated. The plant extracts antibacterial activity was evaluated in vitro and the minimal inhibitory concentration (MIC) was determined by the broth micro-dilution assay. The bacterial killing kinetic was also evaluated for all extracts. In addition, the antibacterial effect of the extracts was tested in vitro on artificial oral biofilms. The acute toxicity of each extract was determined in according to Lorke [Lorke D. A new approach to practical acute toxicity testing. Arch Toxicol 1983;54:275-87] and the antioxidant activity was evaluated by DPPH photometric assay [Mensor LL, Menezes FS, Leitão GG, Reis AS, Santos TC, Coube CS, et al. Screening of Brazilian plants extract for antioxidant activity by the use of DPPH free radical method. Phytother Res 2001;15:127-30]. MIC and the bactericidal concentrations were identical, for each evaluated extract. However, microbes of artificial biofilms were less sensitive to the extracts than the planktonic strains. A. cymbifera extract induced the highest bactericidal effect against all tested bacteria, followed by C. nucifera, Z. joazeiro and C. pyramidalis extracts, respectively. All extracts showed good antioxidant potential, being C. nucifera and C. pyramidalis aqueous extracts the most active ones. In conclusion, all oral bacteria tested (planktonic or in artificial biofilms) were more susceptible to, and rapidly killed in presence of A. cymbifera, C. pyramidalis and C. nucifera than Z. joazeiro extracts, respectively. Thus, these extracts may be of great interest for future studies about treatment of oral diseases, considering their potent antioxidant activity and low toxicity.

Índice de infestação e diversidade de moscas-das-frutas em hospedeiros exóticos e nativos no pólo de fruticultura de Anagé, BA

As moscas-das-frutas (Diptera: Tephritidae) são os principais entraves às exportações de manga nos pólos de fruticultura da Região Sudoeste da Bahia. O presente trabalho teve como objetivo estudar índices de infestação e a diversidade de moscas-das-frutas no pólo de fruticultura de Anagé, BA, visando obter subsídios para o manejo integrado dessas pragas na mangueira, na região. Os estudos foram realizados em 2004 e 2005, nos municípios de Anagé, Belo Campo e Caraíbas, BA, procedendo-se à coleta de frutos de 21 espécies vegetais, nativas e exóticas, e identificação das espécies de moscas associadas. Estimaram-se os índices de infestação em pupários/kg de fruto e pupários/fruto. Os maiores índices de infestação, em pupários/kg de fruto, ocorreram em serigüela (Spondias purpurea L.) com 61,3, juá (Ziziphus joazeiro L.), 38,3 e umbu (Spondias tuberosa L.), 33,1, considerados hospedeiros primários de Anastrepha fraterculus (Wiedemann) e A. obliqua (Macquart). As maiores infestações em pupários/fruto ocorreram em serigüela (0,9); umbu (0,7) e cajarana (Spondias sp.) (0,2). Com base no monitoramento larval, registra-se, para as condições do pólo de fruticultura de Anagé, a ocorrência das espécies Anastrepha fraterculus, A. obliqua, A. dissimilis, A. amita, A. distincta, A. sororcula, A. zenildae e Ceratitis capitata. Registram-se, pela primeira vez, as seguintes associações bitróficas: juá com A. fraterculus, A. obliqua, A. dissimilis e A. distincta; e umbu com A. amita e A. sororcula.

Fenologia reprodutiva e sistema de polinização de Ziziphus joazeiro Mart. (Rhamnaceae): atuação de Apis mellifera e de visitantes florais autóctones como polinizadores

(Fenologia reprodutiva e sistema de polinização de Ziziphus joazeiro Mart. (Rhamnaceae): atuação de Apis mellifera e de visitantes florais autóctones como polinizadores). Ziziphus joazeiro é uma espécie endêmica da Caatinga, com grande utilidade econômica, cuja biologia reprodutiva é pouco conhecida. Este estudo aborda a fenologia reprodutiva, a biologia floral e o sistema de polinização de Ziziphus joazeiro no Cariri Paraibano, Nordeste do Brasil. Os períodos de floração e de frutificação ocorreram no fim da estação seca e início da chuvosa, com picos nos meses de dezembro (floração) e fevereiro (frutificação). As flores são do tipo disco, esverdeadas, duram cerca de 12 horas e possuem disco nectarífero largo e amarelo, o qual circunda o gineceu. Ocorre protandria associada a outro tipo de dicogamia, a heterodicogamia. Ziziphus joazeiro produz néctar em pequena quantidade (1 µl), com alta concentração de açúcares (75%). Os visitantes florais observados foram vespas, abelhas e moscas. Apis mellifera apresentou maior freqüência de visitas (77,5%), seguida pelo grupo das vespas (20,4%), ambos considerados polinizadores efetivos. As moscas e as outras espécies de abelhas apresentaram baixo percentual de visitas (2,1%) e foram consideradas pilhadoras de néctar. A elevada taxa de desenvolvimento inicial de frutos por inflorescência pode sugerir alta eficiência dos polinizadores, uma vez que o mecanismo de dicogamia presente na espécie praticamente impede a ocorrência de autopolinização espontânea e de geitonogamia.

Variações sazonais de aspectos fisiológicos de espécies da Caatinga

No intuito de compreender as estratégias de sobrevivência utilizadas pelas espécies da Caatinga para se adaptarem às condições oferecidas pelo clima da região, avaliaram-se o potencial hídrico e a eficiencia quântica da fotossíntese obtida pela fluorescência das espécies: Myracrodruon urundeuva, Schinopsis brasiliensis, Amburana cearensis,Capparys cynophallophora, Anadenanthera colubrina var. cebil, Pseudobombax sp, Commiphora leptophloeos, Ziziphus joazeiro Bumelia sartorum, Caesalpinia ferrea, Maytenus rigida, considerando-se dois períodos de observação: estiagem (1) e chuvoso (2), para se verificar os possíveis identificadores de estresse. Com relação ao potencial hídrico verificaram-se diferenças estatísticas entre as duas estações, porém o fato que chamou a atenção reside nos altos níveis do potencial hídrico, mesmo no período de estiagem que, caracteristicamente, provocaria o estresse hídrico em função da ausência de água no solo. Os dados de fluorescência revelaram ótimos estados nos aparatos fotossintéticos, não indicando condição de estresse. Concluiu-se que as estratégias de sobrevivência dessas espécies são altamente eficientes e resultam de uma alta complexidade evolutiva.