Passiflora Mucronata Research Articles

Allelopathic potential of aqueous extracts of passion fruit Passiflora mucronata fruit peels on lettuce

Pesticide misuse has led to problems in agriculture, contamination of environment, and human health. However, research into alternative methods of controlling invasive plants is expanding. The allelopathic effect of secondary metabolites from plant parts suggests a potential and sustainable alternative to plant residues for use as bioherbicides. Given the above, the current study aimed to investigate the allelopathic potential of various concentrations of the aqueous extract of fruit peels of genotypes of Passiflora mucronata in seed germination and seedling growth of Lactuca sativa L. Fruit peels of genotypes of P. mucronata were used to obtain an aqueous extract, which was then filtered and diluted at the following concentrations: T1=100; T2=50; T3=25; T4=12.5 mg mL-1; T5= negative control (distilled water) and T6= positive control (glyphosate). Germination was carried out in Petri plates and was conditioned in a biochemical oxygen demand germination chamber at 25 ± 2 °C. Macroscopic evaluation was performed at the germination stage and root and aboveground growth of the seedlings, and the germination velocity index were also evaluated. Cytogenetic analysis was performed, and mitotic index was obtained. The design was entirely randomized, with five repetitions of 25 seeds each. Allelopathic substances found in the bark of P. mucronata fruits interfere with seed germination and vigor, as well as initial seedling growth. The germination of L. sativa seeds was 100% inhibited by extract concentrations of 50 % and 100 %. The cell cycle of L. sativa seeds is inhibited by allelopathic substances present in the bark of P. mucronata fruits. It is concluded that aqueous extracts of Passiflora mucronata have an allelopathic inhibitory effect on germination and initial growth of L. sativa

Qualidade fisiológica de sementes de genótipos de Passiflora mucronataLam. com o doador de óxido nítrico e estresse salino

Abstract The presence of salts in the soil solution reduces the osmotic potential, hindering water absorption by roots. However, plants have defense mechanisms against stresses, releasing signaling molecules, in which nitric oxide plays an important role in the abiotic stress. This study aimed to assess the physiological quality of seeds from Passiflora mucronata Lam. genotypes pre-conditioned with the nitric oxide donor Tadalafil kept under salt stress. Seeds from nine P. mucronata genotypes evaluated under four nitric oxide donor Tadalafil concentrations : 0.0, 1.5, 2.5, 5.0, 7.5, 10.0 and 12.5 mg L-1, applied by soaking seeds for two hours, followed by washing in running water and germination in germitest® paper moistened with NaCl at -1.2 MPa. The experiment was carried out in a completely randomized design, with four replicates of 25 seeds. The nitric oxide donor Tadalafil, at concentrations of 1.5 and 2.5 mg L-1, increased the germination speed, shoot length, and dry mass. Pre-conditioning of seeds with the nitric oxide donor Tadalafil at concentrations of 5.0, 7.5, 10.0, and 12.5 mg L-1 determined the death of seeds. Seeds from genotype G3, pre-conditioned with Tadalafil at concentrations of 1.5 and 2.5 mg L-1, presented higher germination, germination speed index, mean germination time, shoot length, root length and dry matter values. Genotypes presented distinct phenotypic responses, providing intraspecific divergence.

Divergent strategies of nectar secretion in two bat-pollinated Passiflora species

The secretion dynamics and chemical compositions of flower nectar can vary according to the plant physiology and the pollinator type. Bat-pollinated flowers are commonly associated with nocturnal nectar secretion as well as large amounts of nectar per flower, which is generally diluted and composed mostly of hexose sugars. The nectar traits in bat-pollinated Passiflora species are poorly understood and in this work, we describe these for two such species. We conducted field experiments to assess the nectar secretion dynamics of two species with nocturnal anthesis and similar colours and structures, performed chemical analyses of the sugar components of nectar from these two species, and combined these data with systematic observations of floral visitors. The nectar dynamics of both Passiflora species are similar to those of other bat-pollinated species. In Passiflora mucronata, nectar secretion starts before the flower opens, which occurs around 04h00, with secretion ending after 10h00. Passiflora setacea starts secreting nectar at the time of flower opening, around 22h00, finishing secretion between 04h00 and 06h00. In P. setacea, the final period of anthesis is characterised by active nectar resorption. The different blooming times of these two bat-pollinated passionflowers and the significant differences in their nectar secretion schedules suggest a divergent nectar secretion dynamics: the nectar of P. mucronata is made available only by the end of the bats’ foraging activity period, continuing throughout the morning, while P. setacea secretes nectar earlier, with very little overlap in the secretion period between the species. We hypothesise that this segregation in time helps avoid the negative effects from competition for pollinators or pollen interference between flowers with a similar structure, while the outstanding nectar traits and the constant production of flowers throughout the year make these closely related vines important nectar sources for their bat pollinators where they co-occur.

Passiflora mucronata, a passion fruit wild species resistant to fusariosis and a potential rootstock for commercial varieties

Passiflora mucronata Lam. offers a reservoir for the control of fusariosis in passion fruit. Fusariosis, a fungal disease caused by Fusarium oxysporum f. sp. passiflorae and species of the Fusarium solani complex, can dramatically reduce productivity and lead to premature death of infected plants. This study aimed to assess the resistance of ten P. mucronata genotypes (G1 to G10) to F. oxysporum f. sp. passiflorae and F. solani isolates. Plants grown for 45 days in autoclaved soil, were inoculated with i) two separate F. oxysporum f. sp. passiflorae isolates, ii) a mixture of three F. oxysporum f. sp. passiflorae isolates, iii) two separate F. solani isolates, and iv) a mixture of seven F. solani isolates. The roots were immersed in a spore suspension for 60 min and plantlets were grown for 90 days. Inoculated plants of G2 and G5 exhibited the same growth and accumulation of shoot and root dry matter as non-inoculated plants, 100% survival, and no internal or external tissue damage, suggesting immunity to fusariosis. Genotype G9 grew normally in a disease-prone environment, suggesting horizontal resistance. These genotypes can be used as rootstocks for breeding of commercial passion fruit varieties, as they can be classified resistant to F. oxysporum f. sp. passiflorae and F. solani isolates.

Cryoprotectants and X-ray analysis on Passiflora seeds cryopreserved

The study aimed to evaluate the internal morphology of Passiflora eichleriana Mast., Passiflora nitida Kunth. and Passiflora mucronata Lam. seeds cryopreserved with different cryoprotectants. The treatment were control (without cryoprotectant or cryopreservation), seeds cryopreserved without cryoprotectant, 1.73, 2.28, 2.60 or 2.71 M glycerol, 0.37, 0.46, 0.54 or 0.61 M sucrose and 0.37, 0.72, 1.04 or 1.35 M dimethylsulfoxide. The seeds were cryopreserved in liquid nitrogen (-196 °C) for seven days. The cryopreserved seeds were dipped in water bath (37 °C) for 5 minutes to defrost. The percentage of filled, empty, malformed and damaged seeds was determined. The seeds were analyzed by X-ray to verify damages caused by the cryopreservation or defrost. Our results demonstrate that X-ray is an efficient method to analyses cryopreserved seeds and the cryopreservation technique did not cause mechanical damage of P. eichleriana, P. nitida and P. mucronata seeds.

Initial growth of clonal seedlings of Passiflora mucronata genotypes in response to paclobutrazol concentrations

Paclobutrazol (PBZ) is a plant growth regulator of the triazole group that can block the biosynthesis of gibberellic acid, resulting in reduced plant height and increased stem diameter. This study aimed to evaluate the effect of different paclobutrazol concentrations on seedling quality of Passiflora mucronata Lam. Two Passiflora mucronata genotypes were used, one resistant (G5) and one tolerant (G7) to fusariosis, prepared as cuttings treated with PBZ. The experimental design was completely randomized, in a 2 x 4 factorial arrangement corresponding to two genotypes (G5 and G7) and four PBZ concentrations (0, 5, 10, and 15 mg plant-1), with three replications of four plants. Data were subjected to analysis of variance, regression analysis, and the F-test, followed by Pearson’s correlation test between variables. PBZ promoted an increase in the plagiotropic shoot diameter and the leaf area index of genotypes G5 and G7, in addition to increased shoot length in genotype G5 and increased number of leaves in genotype G7. PBZ also resulted in increased photosynthesis and stomatal conductance. There was a positive correlation for genotype G5, between the plagiotropic shoot diameter and the leaf transpiration rate, and for genotype G7, between the plagiotropic shoot diameter and the number of leaves. Genotypes G5 and G7 showed different phenotypic responses when subjected to PBZ doses, highlighting the intraspecific divergence of the species.

Passiflora mucronata leaves extracts obtained from different methodologies: a phytochemical study based on cytotoxic and apoptosis activities of triterpenes and phytosterols constituents

Cancer is one of the most prevalent diseases worldwide and the natural products could be a source of bioactive compounds. Passiflora mucronata (PM) belongs to a very known vegetal genus, although, there are no studies about cytotoxic activity or isolated compounds. Different extracts from PM were obtained by liquid-liquid partition (P), Soxhlet (Sox) and supercritical fluid (SFE1-5) extraction techniques, being compared concerning their yields, chemical profile and cytotoxicity. The Sox extracts showed the highest yields (6.03%: hexane; 2.51%: dichloromethane) followed by SFE (from 4.34 to 1.63%) and partitions (1.06 and 2.26%). The hexane partition (HP) showed the best cytotoxic activity against K562 cell line (IC50 = 18.72 µg.mL-1). From HP, the following compounds were identified and analysed its cytotoxic activities: β-amyrin (IC50 = 3.92 µg.mL-1), β-sitosterol (IC50 = 3.37 µg.mL-1), stigmasterol (IC50 = 3.31 µg.mL-1) and oleanolic acid. Stigmasterol induced about 75% of K562 total apoptosis. The compounds were tested against MA-104 cell line and the selective index (SI) attributed (SI >10 for all compounds). This indicates good selectivity to K562 cell line at the expense of MA-104. This is the first time, identifying those compounds to PM .

Crioprotetores na criopreservação de sementes de Passiflora mucronata Lam

Brazil is one of the centers of diversity of the genus Passiflora L . and therefore has great potential for the utilization of the genetic resources in agronomy. Passiflora mucronata Lam. is a wild species that presents great characteristics for ornamental use. This work aimed to evaluate the effect of different concentrations of cryoprotectants dimethylsulfoxide (DMSO) and sucrose (0, 7, 14, 21 and 28%) on the cryopreservation of Passiflora mucronata seeds. After the application of the cryoprotectants, the seeds were stored in liquid nitrogen for 5 days, thawed, and later, seeded in vermiculite and maintained at a temperature of 27.7 ± 1.9°C. The cryoprotectant type and the application of increasing doses affect the physiological quality of seeds after storage in liquid nitrogen. Cryopreservation may be used for the long-term conservation of seeds, without the use of cryoprotectants.

Apoptosis Caused by Triterpenes and Phytosterols and Antioxidant Activity of an Enriched Flavonoid Extract from Passiflora mucronata.

P. mucronata (Pm) comes from South America, Brazil and is characterized as "Maracujá de Restinga". It is used in folk medicine for its soothing properties and in treating insomnia. The present study for the first time analyzed the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. The cytotoxicity test will be evaluated by different assays (MTT and CV) against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, and the antioxidant test by DPPH method. β-Amyrin, oleanolic acid, β-sitosterol and stigmasterol were isolated of the most active, hexane fraction. These substances were tested against the tumor cell lines: β-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, it was possible to indicate that the mode of cell death for stigmasterol, presumably is apoptosis. In terms of antioxidant activity, the hydroalcoholic leaves extract presented higher activity (EC50 133.3 µg/mL) compared to the flower (EC50 152.3 µg/mL) and fruit (EC50 207.9 µg/mL) extracts. By the HPLC-MS, it was possible to identify the presence of flavones in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin). P. mucronata hexane fraction showed promising cytotoxic effect against cancer cell lines, and stigmasterol contributes to this activity, inducing apoptosis of these cells. Furthermore, as other Passiflora species, Pm extract showed antioxidant activity and flavones are its major phenolic compounds.

Characterization of the Essential oil of the Bat-Pollinated Passiflora mucronata

The genus Passiflora is an important source of food, therapeutic substances and for the horticultural economy. In the last decades, a detailed chemical composition of the essential oil of Passiflora species has been reported, but only for few species, mainly of agricultural interest, although little attention has been paid to chiropterophilous Passifloraceae, such as P. mucronata. The present study is focused on analyzing the essential oil composition of P. mucronata, a Brazilian bat-pollinated species. From GC/FID and GC/MS analyses of the volatile fraction from fresh flowers and leaves, hydrocarbons were quantified as 47.9% and 42.8% of the total volatiles of flowers and leaves, respectively, esters for 50.8% in flowers and 6.4% in leaves, and alcohols 38.2% and 0.3% of the total volatiles from leaves and flowers, respectively. Other classes of compounds, such as monoterpenes and aldehydes, together with phytol, were detected in higher concentration in leaves compared with flowers. The higher content of methyl and ethyl esters of long chain saturated and unsaturated fatty acids, i.e. ethyl linolenate (38.3%), methyl linolenate (7.0%) and ethyl palmitate (3.6%), were the most representative suggesting that esters might play a critical role for fertilization of P. mucronata acting as bat attractors.

Biological activities and phytochemical profile of Passiflora mucronata from the Brazilian restinga

In general, Passiflora species have been reported for their folk medicinal use as sedative and anti-inflammatory. However, P. caerulea has already been reported to treat pulmonary diseases. Severe pulmonary tuberculosis, generally caused by Mycobacterium tuberculosis strains resistant to multiple drugs, can lead to deleterious inflammation and high mortality, encouraging new approaches in drug discovery. Thus, the aim of this work was to evaluate the Passiflora mucronata Lam., Passifloraceae, potential for tuberculosis treatment. Specifically, related to antimycobacterial activity and anti-inflammatory related effects (based on inhibition of nitric oxide, tumor necrosis factor-alpha production and antioxidant potential), as well as the chemical profile of P. mucronata. High performance liquid chromatography coupled with diode-array ultraviolet and mass spectrometer analyses of crude hydroalcoholic extract and ethyl acetate fraction showed the presence of flavonoids. Ethyl acetate fraction showed to be as antioxidant as Ginkgo biloba standard extract with EC50 of 14.61±1.25μg/ml. One major flavonoid isolated from ethyl acetate fraction was characterized as isoorientin. The hexane fraction and its main isolated compound, the triterpene β-amyrin, exhibited significant growth inhibitory activity against Mycobacterium bovis BCG (MIC50 1.61±1.43 and 3.93±1.05μg/ml, respectively). In addition, Passiflora mucronata samples, specially hexane and dichloromethane fractions, as well as pure β-amyrin, showed a dose-related inhibition of lipopolysaccharide (LPS)-induced nitric oxide production. In conclusion, Passiflora mucronata presented relevant biological potential and should be considered for further studies using in vivo pulmonary tuberculosis model.

Growth dynamics and allometric relationships of Passiflora species rootstocks

Passion fruit (Passiflora edulis Sims) is characterized by being a tropical fruit, with significant production in Brazil, however the occurrence of diseases, especially fungal infections that affects the root system, has reduced its production. Some Passifloraceae species are reported as being resistant to these pathogens, which feature in potential rootstock for P. edulis cultivation in contaminated areas, although the patterns of growth and development of these species has not being elucidated yet. Thus, the objective was to study the dynamics of growth and evaluate the dry matter distribution of passion fruit with potential rootstock use. Passiflora cincinnata, Passiflora mucronata, Passiflora giberti, Passiflora morifolia and Passiflora edulis (control) developed in polyvinyl chloride tubes of 100 mm in diameter and 150 cm in height, in order to assess plant height, leaf area, number of secondary roots, stem diameter, taproot lenght, root system volume, absolute growth rate, relative growth rate, net assimilation rate, leaf mass ratio and root mass ratio, at 30, 45, 60, 75, 90 and 105 days after transplanting. The species P. cincinnata, P. giberti and P. morifolia presented higher or similar growth rates than P. edulis for all evaluated characteristics, throughout the evaluation period. The root system of the species P. giberti and P. morifolia showed better distribution along the substrate. The species P. mucronata obtained lower growth than other species, both for the shoot and the root system.

Desenvolvimento, florescimento e análise morfoanatômica do maracujazeiro-amarelo enxertado em espécies silvestres do gênero passiflora

Soil diseases reduce the lifetime of the yellow passion fruit crops, forcing the practice of shifting cultivation. The use of tolerant rootstocks could help control premature demise of plants, providing healthier crops, uniform and long-lived. This paper has aimed quantify the influence of two species of wild passionfruit Passiflora mucronata Lam and P. gibertii NE Brown as rootstocks on the agronomic characteristics of yellow passion fruit. The morphological and anatomical analysis of graft region highlighted the cellular redifferentiation resulting in the connection of the graft and the rootstock hypo and epibioto tissues. The changes in characteristics such as plant height, number of nodes, occurrence rate of nodes, accumulation of thermal units to flowering also discussed. It was observed that P. mucronata as rootstock positively influenced the number of nodes, plant height, the number of flowers and the rate of occurrence of nodes. The wild species used as rootstock developed flower buds prematurely. The specie P. mucronata showed the best performance as rootstock.

Different propagules and auxin concentration on rooting of passionflower sandbank

ABSTRACT Passiflora mucronata Lam. is resistant to Fusarim oxysporum f. passifloraceae and therefore can be used as rootstock for the species Passiflora edulis Sims. f. flavicarpa. The rootstocks in this case can be vegetatively propagated through cuttings. The objective of this study was to evaluate the effect of different types of cuttings and different concentrations of indole-3-butyric acid (IBA) on the adventitious rooting of P. mucronata. The experiments were arranged in a completely randomized design with four replications of 16 cuttings each. In Experiment 1, the treatments consisted of the different types of cuttings from mother plants grown in protected environment: shoot tips; two leaves and two nodes; one leaf and one node; leafless with two nodes; leafless with one node. In Experiment 2, the cuttings were taken from field plants and treated with the following IBA concentrations: 0; 1000 mg kg-1 (0.0036456 mol L-1); 1500 mg kg-1 (0.0054684 mol L-1) and 2000 mg kg-1 (0.0072912 mol L-1). The characteristics evaluated in the experiments 1 and 2 were: survival (1 and 2); budding (1 and 2); shoot number (2), shoot length (2), number of shoot leaves (2);shoot dry mass (2); callusing (1); rooting (1 and 2); root number (1 and 2), largest root length (1 and 2), root volume (1 and 2), and root dry mass (1 and 2). We found that, instead the shoot tips, the cuttings of the type leafless with two nodes are the best for P. mucronata rooting. Neither the cuttings from greenhouse plants nor the cuttings from field plants require growth regulators for rooting of P. mucronata cuttings of the type leafless with two nodes.

Seed cryopreservation of Passiflora species

Abstract The aim of this study was to evaluate the cryopreservation of seeds of Passiflora species, using different cryoprotectants. The completely randomized design was used with four treatments (T1 - DMSO at 7%; T2 - 0.3 M sucrose; T3 - storage in NL2 without cryoprotectants; T4 - control) and five replications of 50 seeds. The seeds were stored for 120 hours in NL2 (-196 °C), and thawing was conducted in a water bath (37 °C) for 20 minutes, proceeding with the germination and vigor tests. The data were submitted to ANOVA and Tukey's test (5% of probability) using the SISVAR program. In P. mucronata, P. suberosa and P. edulis seeds, the responses obtained were favorable to cryopreservation without the use of cryoprotectants in regards to P. micropetala, there was a considerable loss of germination potential after storage in NL2. Given these circunstances, cryopreservation can be used for long-term conservation of Passiflora mucronata, P. suberous and P. edulis, without the use of cryoprotectants.

Effect of two wild rootstocks of genus Passiflora L. on the content of antioxidants and fruit quality of yellow passion fruit

The nutritional importance of the fruit of passionfruit has prompted studies to assess its composition and antioxidant content and to evaluate it as a functional food in fresh fruit and concentrated juice markets. Currently, the use of wild species as rootstock has been recommended mainly for their positive effects such as tolerance to disease attack and maintenance of fruit quality of grafted cultivars. The aim of this study was to determine the effect of wild species of Passiflora gibertii N.E. Br. and Passiflora mucronata Lam as rootstock on the content of antioxidants and fruit quality of Passiflora edulis f. flavicarpa. The experimental design was completely randomized with four treatments and 25 replications, with a total of 100 experimental units. As a control treatment, plants of P. edulis from seed and grafted on the same species were used. Significant correlations were observed among the contents of β-carotene, ascorbic acid, luminosity values, chroma and hue angle. For the combination P. edulis/P. gibertti, the contents of β-carotene and ascorbic acid were highly correlated with luminosity, chroma and hue angle of fruit juice. A similar behavior was observed for the combination P. edulis/P. mucronata Lam. The content of β-carotene in the fruit showed no statistical differences (p < 0.05), indicating no significant rootstock effect on the variables evaluated. The results indicate a potential wild rootstock use for its positive effects on grafted plants while maintaining the commercial quality of the fruits of passionfruit crops.

Resistance to Fusarium solani and characterization of hybrids from the cross between P. mucronata and P. edulis

The development of resistant cultivars is an alternative to control phytosanitary problems affecting passion fruit crops. This study was conducted to obtain progenies through interspecific crosses between Passiflora edulis × Passiflora mucronata, perform the genetic assessment of the progenies obtained, and evaluate and select genotypes resistant to Fusarium solani. When P. mucronata was used as female parent, 516 seeds were obtained, with 20 % germination and survival of nine hybrid genotypes. On the other hand, in the reciprocal cross, 9 seeds were obtained and only one genotype survived. Due to the small number of genotypes obtained, 10 hybrid genotypes and their parents P. edulis (susceptible) and P. mucronata (resistant) was propagated by cuttings. Nine plantlets of each genotype were taken to the field in a randomized block design, with three replications, aiming at morphological characterization. Twenty quantitative and 7 qualitative descriptors were assessed. Nine clones of each individual were kept in a greenhouse, inoculated with F. solani, and assessed 76 days after inoculation. Later, the fungus was re-isolated. The offspring genotypes of the cross in which P. edulis was the female parent did not flourish. For most quantitative and qualitative traits, hybrids were similar to P. mucronata. The genotypes studied formed six groups. Resistance to the fungus was detected in the genotypes of P. mucronata, from Bahia, and two hybrid genotypes. The resistant hybrid can be backcrossed with P. edulis and/or used as rootstock for sour passion fruit.

CARACTERIZAÇÃO FÍSICA E QUÍMICA DE FRUTOS DE MARACUJAZEIRO-AMARELO ENXERTADO EM ESPÉCIES SILVESTRES DO GÊNERO PASSIFLORA CULTIVADO EM AMBIENTE PROTEGIDO

RESUMO O mercado de frutas frescas do maracujá-amarelo valoriza as qualidades interna e externa dos frutos. O uso de espécies silvestres como porta-enxertos tem sido preconizado como possível medida de controle de doenças. São escassas as informações sobre o efeito de espécies silvestres do gênero Passiflora como porta-enxertos sobre as características físicas e químicas em frutos de maracujazeiro. O objetivo deste trabalho foi determinar a influência de duas espécies de passifloráceas silvestres P. mucronata Lam e P. gibertii N.E. Brow como porta-enxertos sobre as características físicas e químicas dos frutos do maracujazeiro-amarelo em ambiente protegido. Adotou-se o delineamento inteiramente casualizado, com quatro tratamentos e 25 repetições, consistindo em 100 parcelas. Cada parcela foi representada por uma planta conduzida em vaso de 30 L. Os porta-enxertos avaliados foram: Passiflora edulis Sims, Passiflora gibertii N.E. Brow e Passiflora mucronata Lam. Comotratamento-testemunha, foram utilizadas plantas de P. edulis Sims provenientes de sementes. Avaliaram-se a massa fresca do fruto (MF), a massa fresca da casca (MC), a massa fresca da polpa (MP), o diâmetro do fruto (DF), o comprimento longitudinal do fruto (CF), a espessura da casca dos frutos (EC), a coloração do suco e da casca dos frutos, o teor de sólidos solúveis (SS), a acidez titulável (AT), a relação SS/AT, a relação MP/MF e o teor de vitamina C (ácido ascórbico). As plantas enxertadas sobre espécies silvestres produziram frutos mais alongados que as plantas provenientes de sementes, porém dentro dos padrões de comercialização.

Auxin and physical constraint exerted by the perianth promote androgynophore bending in Passiflora mucronata L. (Passifloraceae).

The androgynophore column, a distinctive floral feature in passion flowers, is strongly crooked or bent in many Passiflora species pollinated by bats. This is a floral feature that facilitates the adaptation to bat pollination. Crooking or bending of plant organs are generally caused by environmental stimulus (e.g. mechanical barriers) and might involve the differential distribution of auxin. Our aim was to study the role of the perianth organs and the effect of auxin in bending of the androgynophore of the bat-pollinated species Passiflora mucronata. Morpho-anatomical characterisation of the androgynophore, including measurements of curvature angles and cell sizes both at the dorsal (convex) and ventral (concave) sides of the androgynophore, was performed on control flowers, flowers from which perianth organs were partially removed and flowers treated either with auxin (2,4-dichlorophenoxyacetic acid; 2,4-D) or with an inhibitor of auxin polar transport (naphthylphthalamic acid; NPA). Asymmetric growth of the androgynophore column, leading to bending, occurs at a late stage of flower development. Removing the physical constraint exerted by perianth organs or treatment with NPA significantly reduced androgynophore bending. Additionally, the androgynophores of plants treated with 2,4-D were more curved when compared to controls. There was a larger cellular expansion at the dorsal side of the androgynophores of plants treated with 2,4-D and in both sides of the androgynophores of plants treated with NPA. This study suggests that the physical constraint exerted by perianth and auxin redistribution promotes androgynophore bending in P.mucronata and might be related to the evolution of chiropterophily in the genus Passiflora.

Enraizamento adventício de estacas do maracujazeiro silvestre Passiflora mucronata Lam.: forma de veiculação e concentrações do ácido indol-3-butírico

Passiflora mucronata Lam. apresenta como características ser ornamental, medicinal e resistente à bacteriose nas folhas, além de ser altamente resistente à antracnose nos frutos e ramos. Objetivou-se, com este trabalho, avaliar a forma de veiculação, líquida ou sólida, e as concentrações do ácido indol-3-butírico (AIB) no enraizamento adventício de estacas de P. mucronata. O experimento foi conduzido no delineamento de blocos ao acaso, em esquema fatorial 2x5 (formas de veiculação do AIB: líquida e sólida x concentrações de AIB: 0; 250; 500; 750 e 1000 mg L-1, se líquido, ou mg Kg-1, se sólido), com quatro repetições, de 16 estacas cada. As características avaliadas foram enraizamento (%), número de raiz, comprimento da maior raiz (cm), volume de raiz (cm³) e massa de matéria seca de raiz (g). Verificou-se que o enraizamento de estacas de P. mucronata Lam. independe da forma como é veiculado o AIB, se sólida ou líquida, porém a qualidade do sistema radicular, avaliada por meio do número, volume e massa de matéria seca de raízes, foi superior à obtida ao se empregar o AIB sólido. O comportamento do enraizamento, do número e do comprimento de raízes foi linear crescente, até a máxima concentração de AIB (1000 mg L-1 ou mg Kg-1).