Comparative cytogenetics between the species Passiflora edulis and Passiflora cacaoensis

Passiflora edulis Sims is the most economically important species of the genus Passiflora. A new species was described recently, Passiflora cacaoensis Bernacci & Souza, which displayed morphologic characteristics very similar to P. edulis. Due to the need for delimitation of the two species, karyomorphological and banding analyses were carried out. Both species have 2n = 18, with the same karyotype formula 16 m + 2sm. There was variation between the species regarding the location of satellites and the width of chromosome pairs 2, 4 and 8. C banding revealed the presence of constitutive heterochromatin in the centromeric and telomeric regions of all chromosomes in both species. However, only in P. cacaoensis did chromosomes 3 and 9 have a large quantity of heterochromatin. Fluorochrome banding revealed CMA⁺ bands only in the satellites, but no DAPI⁺ bands. Fluorescence in situ hybridisation (FISH) showed that in P. cacaoensis the rDNA 5S probe is located in a single site in the subterminal position of the long arm of chromosome 5. However, for the rDNA 45S probe, two sites were detected in terminal positions of the long arms of chromosome 7, with a bigger and stronger signal, and of chromosome 9. According to the asymmetry index and the quantity of heterochromatin, P. cacaoensis is a more basal species than P. edulis. The cytogenetic data indicate that P. cacaoensis is closely related to P. edulis, but is a different species.     

Passiflora tacanensis, a new species of Passiflora subgenus Decaloba supersection Cieca from Mexico

Passiflora tacanensis, a new species from southern Mexico, is described and illustrated. It was discovered during the course of a taxonomic revision ofPassiflora subgenusDecaloba supersectionCieca and is assigned to that group of apetalous passion flowers.Passiflora tacanensis is known only from one fruiting herbarium specimen that was collected in southern Mexico on Volcán Tacaná in a high mesophytic forest. It is distinguished from its closest relatives,P. coriacea, P. sexocellata, P. mcvaughiana, andP. xiikzodz, by its foliose stipules, leaves that lack laminar nectaries but possess petiolar nectaries, and wide seeds with a chalazal beak that is not well developed.     

1056. Passiflora bakhuisensis Vanderplank & Boender

Passiflora bakhuisensis (plate 1056) a new species of Passiflora L. in subgenus Astrophea (DC.) Mast., supersection Astrophea, section Dolichostemma Killip from Surinam is described; its taxonomy, distribution and cultivation are discussed, and a key to this and related species is provided. A new synopsis of subgenus Astrophea (DC.) Mast., supersections Astrophea and Pseudoastrophea (Harms) Feuillet & J. M. MacDougal is provided.     

Origin of the cultivated passion fruit Passiflora edulis f. flavicarpa and genomic relationships among species of the subgenera Decaloba and Passiflora

• Passiflora edulis f. flavicarpa is the most economically important species in the genus Passiflora. However, the origin of this yellow form of passion fruit remains unclear, being suggested as a hybrid (P. edulis f. edulis × P. ligularis) or wild mutant.
• Here, the origin and genomic relationships of P. edulis f. flavicarpa with some related species in the genus Passiflora (subgenera Decaloba and Passiflora) were investigated using genomic in situ hybridization (GISH). Genomic DNA of 18 species was used as probe, which was hybridized onto chromosomes of P. edulis f. flavicarpa.
• Of all genomic DNA probes tested, none allowed us to identify a specific chromosome set in P. edulis f. flavicarpa. Conversely, probes from the subgenus Passiflora, P. edulis f. edulis, P. alata, P. cincinnata, P. coccinea, P. nitida and P. vitifolia, produced intense and uniform hybridizations on all chromosomes of P. edulis f. flavicarpa. Moreover, probes from P. ligularis, P. foetida and P. sublanceolata produced more intense hybridizations in the terminal region of four chromosomes, corresponding to the DNAr 45S locus, and also dispersed, less intense, hybridization across all chromosomes. Probes from the subgenus Decaloba, P. biflora, P. capsularis, P. cervii, P. coriacea, P. micropetala, P. morifolia, P. rubra and P. suberosa, produced hybridizations restricted to the DNAr 45S sites.
• The hybrid origin of P. edulis f. flavicarpa could not be supported based on the GISH results, and it is suggested that this species is conspecific with P. edulis f. edulis, because the probe with DNA of this form hybridized strongly throughout the target genome. The other putative parent species, P. ligularis, showed only a distant relationship with the target genome. The results also suggest that species of the subgenus Passiflora share many repetitive sequences and that the relationship between subgenera Decaloba and Passiflora is very distant.

     

Glycosidic Inhibitors of Melanogenesis from Leaves of Passiflora edulis

A new flavonoid glycoside, chrysin 6‐C‐β‐rutinoside (chrysin α‐L ‐rhamnopyranosyl‐(1→6)‐C‐β‐glucopyranoside; 2 ), and two new triterpene glycosides, (31R)‐31‐O‐methylpassiflorine ( 7 ) and (31S)‐31‐O‐methylpassiflorine ( 8 ), along with 14 known glycosides, including three flavonoid glycosides, 1, 3 , and 4 , six triterpene glycosides, 5, 6 , and 9 – 12 , three cyano glycosides, 13 – 15 , and two other glycosides, 16 and 17 , were isolated from a MeOH extract of the leaves of Passiflora edulis (passion flower; Passifloraceae). The structures of new compounds were elucidated on the basis of extensive spectroscopic analysis and comparison with literature data. Upon evaluation of compounds 1 – 17 against the melanogenesis in the B16 melanoma cells induced with α‐melanocyte‐stimulating hormone (α‐MSH), three compounds, isoorientin ( 1 ), 2 , and (6S,9R)‐roseoside ( 17 ), exhibited inhibitory effects with 37.3–47.2% reduction of melanin content with no, or almost no, toxicity to the cells (90.8–100.2% cell viability) at 100 μM . Western blot analysis showed that compound 2 reduced the protein levels of MITF, TRP‐1, and tyrosinase, in a concentration‐dependent manner while exerted almost no influence on the level of TRP‐2, suggesting that this compound inhibits melanogenesis on the α‐MSH‐stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of TRP‐1 and tyrosinase. In addition, compounds 1 – 17 were evaluated for their inhibitory effects against the Epstein? Barr virus early antigen (EBV‐EA) activation induced by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells.     

Shoot regeneration from mature endosperm of Passiflora foetida

Murashige and Skoog (1962) medium supplemented with 2 M 6-benzylaminopurine (BA) induced adventitious shoots on mature endosperm explants, whilst gibberellic acid (GA₃) and casein hydrolysate stimulated growth and development of these shoot primordia. Plantlets were successfully weaned in vivo. These plants were found to be triploid and flowered, although fruit set was not observed.     

Studies in Brazilian Passifloraceae III. A new species of Passiflora

A new species ofPassiflora from Minas Gerais, Brazil, is described and namedP. saccoi. This species belongs to subgenusPassiflora seriesLobatae harms because of its lobed leaves, foliaceous, semi-ovate to semi-oblong stipules that are attached on one side above base and, hence, often appear sub-reniform, and foliaceous, verticillate bracts borne near the apex of the peduncle.     

Karyology and cytotaxonomy of the genus Passiflora L. (Passifloraceae)

 The chromosomes of 31 species of Passiflora, distributed throughout the subgenera Astrophea, Calopathanthus, Distephana, Dysosmia, Passiflora, Plectostemma and Tacsonia were analysed. Three different karyotypes were observed: 2n = 12, 24, 36; 2n = 18, 72 and 2n = 20. The karyotype of these species was almost always constituted of metacentric and submetacentric chromosomes with variable karyotype symmetry. In the group with x = 6, represented by the subgenus Plectostemma, six diploid species with 2n = 12, one tetraploid with 2n = 24 (P. suberosa) and an intraspecific polyploid with 2n = 12, 36 (P. misera) were analysed. P. pentagona (subgenus Astrophea) may also be included in this karyological group since it presents 2n = 24 and may be of polyploid origin, with x = 6. The interphase nuclei in this group were areticulate, except those of P. morifolia and P. pentagona with semi-reticulate characteristics. Two small terminal heterochromatic blocks, positive for chromomycin A₃, were identified in the largest chromosome pair of P. capsularis and P. rubra, species very closely related, while P. tricuspis displayed four chromosomes with proximal blocks. In the group with x = 9, represented mainly by subgenus Passiflora, 20 species with 2n = 18 and one with 2n = 72 were studied. They presented chromosomes larger than those species with x = 6 and interphase nuclei of semi-reticulate type, except for P. mixta with areticulate nuclei. Four terminal CMA⁺ blocks were observed in P. edulis, six blocks in P. caerulea and P. racemosa, while five blocks were observed in the single P. amethystina plant analysed. P. foetida (subgenus Dysosmia), the only species with 2n = 20, exhibited six chromosomes with CMA⁺ blocks and interphase nuclei of the areticulate type. The meiotic analysis of representatives of the three groups (P. foetida, P. suberosa, P. cincinnata and P. racemosa) always presented regular pairing and regular chromosome segregation, except in P. jilekii where a tetravalent was observed. The analysis of the chromosome variation within the genus and the family suggests that the base number of Passiflora may be x₁ = 6 or x₁ = 12, whereas x₂ = 9 is only an important secondary base number. Received April 11, 2000 Accepted October 5, 2000     

A virus causing ringspot of Passiflora edulis in the Ivory Coast

A mechanically transmissible virus causing leaf mottling and ringspotting of Passiflora edulis var. flavicarpa in the Ivory Coast is described. Its particles are flexuous rods 810–830 nm long and 15 nm wide. It infects mainly species of Passifloraceae and Leguminosae; Passiflora foetida is a good diagnostic host. Aphis gossypii and Aphis spiraecola transmit the virus after brief acquisition feeds. Seed transmission was not detected. In crude sap of P. edulis, infectivity was lost after 10 min at 65–70 °C, 12–14 days at 24 °C or dilution to 10^-7. A purification method is described, using Triton-X-100 as clarifying agent. The virus is serologically related but not identical to passionfruit woodiness virus from Queensland. The virus seems to belong to the potato virus Y group and has the cryptogram */*:*/(6):E/E:S/Ap. It is designated passionfruit ringspot virus.     

A new species of Passiflora (Passifloraceae) from Amazonian Brazil

Passiflora cordistipula, a new species of subg.Passiflora, ser.Lobatae, from the state of Amazonas, Brazil, is described and illustrated.     

Pollination intensity and potential seed set in Passiflora vitifolia

Summary Initial seed set and fruit set were pollen-limited in a Costa Rican population of Passiflora vitifolia, a self-incompatible species with 200–350 ovules per flower. Pollination intensity was measured by counting the number of allogamous pollen grains on stigmas of the large one-day flowers. Hand-pollinations demonstrated that 25–50 pollen grains are required for fruit set, and >450 are needed for maximum seed set, with a pollen:seed ratio of about 1.6:1.0. Hummingbirds (Phaethornis superciliosus) delivered sufficient allogamous pollen for maximum seed set to only 28% of the flowers examined. Naturally pollinated flowers yielded fewer fruits and fewer seeds per fruit than those pollinated by hand. Most pollen transferred by humming-birds was self-incompatible; emasculated flowers yielded higher seed set than flowers with intact anthers. Visitation rates did not provide a good index of effective pollination.There were significant differences in ovule number, maximum seed set, and maximum per cent seed set among individual vines. More than half of an individual's flowers failed to set fruit, whether pollinated by birds or by hand. In this population, maximum reproductive potential may be limited by maternal resources for fruit development, but seed set varies with pollination intensity. Pollen-limited seed set may be a disadvantage of self-incompatibility, especially in species with many-seeded fruits.     

In vitro culture of adult and juvenile bud explants of Passiflora species

Cultivar E23, an F1 hybrid of P. edulis and P. edulis f. flavicarpa is usually propagated by shoot-tip grafting. Various media were tested to evaluate the potential of E23 for in vitro propagation. Adult tissue was difficult to culture and did not respond to media containing low (<10 µM) concentrations of growth regulators. Growth of adult buds on intact stem sections was promoted by 1 week of dark incubation on MS basal medium plus 150 µM 2iP, 200 µM adenine sulphate and 17.1 µM IAA (3 mg l^–1), and further developed into shoots on MS medium plus 4.9 µM 2iP (1 mg l^–1) and 5.7 µM IAA (1 mg l^–1). By contrast, juvenile shoots of E23, and Passiflora species: edulis f. flavicarpa, edulis, alata, caerulea, mollissima, coccinea, herbertiana and suberosa grew rapidly on MS medium plus 10 µM kinetin and 5 µM IAA. Rapid multiplication was achieved on MS plus 20 µM BA, 10 µM kinetin, 5 µM IAA, and roots initiated on MS plus 5 µM IAA.Abbreviations IAA indole-3-acetic acid - 2iP N6-iso pentenyl adenine - BA N6-benzyl adenine     

Pre-analytical method for metabolic profiling of plant cell cultures of Passiflora garckei

Passiflora garckei cell cultures were used as a model to describe a reproducible sample preparation method. Solid phase extraction (SPE) was employed to isolate the plant metabolites for nuclear magnetic resonance (NMR) analysis and to subsequently detect the differences between yeast extract elicited and control cells. Compared with previous results obtained by using a Sephadex LH-20 column, SPE coupled with NMR spectroscopy improves the analysis of aromatic compounds e.g.: trans-feruloyl derivatives and trans-coumaroyl derivatives. Moreover, it decreases the concentration of sugars that usually overlap with many plant metabolite signals.     

A new species of Passiflora (Passifloraceae) from Minas Gerais, Brazil

Passiflora boticarioana, a new species of subgen.Passiflora, supersect.Stipulata, sect.Dysosmia, from the state of Minas Gerais, Brazil, is described, illustrated, and compared with morphologically similar species.     

Auxin Transport in Tendril Segments of Passiflora caerulea

The movement of auxin through tendril segments of Passiflora caerulca L. has been investigated using IAA-2-¹⁴C. It has been shown that (1) flux of IAA through the segments is strongly polarized basipetally: (2) the amount of ¹⁴C recovered in the basal receiver blocks increases linearly within a transport period of 6 h; (3) velocity of basipetal transport is 14.5 mm h^?1; (4) at least 70% of the radioactivity in the receiver blocks is confined to the IAA molecule: approximately 55% of ¹⁴C from methanolic extracts of the segments is IAA: (5) at low temperatures (2–4°C) the basipetal transport is abolished; (6) white light promotes basipetal transport, and this effect is abolished in a CO₂-free atmosphere; (7) no difference could be detected in ¹⁴C content between dorsal and ventral halves of tendril segments nor among individual dorsal and ventral receiver blocks.     

Competition hierarchy and plant defense in a guild of ants on tropical Passiflora

In facultative ant–plant interactions, ants may compete with each other for food provided by extrafloral nectar (EFN) plants. We studied resource competition and plant defense in a guild of ants that use the same EFN resource provided by two species of Passiflora in a seasonal rain forest in tropical China. At least 22 ant species were recorded using the EFN resource, although some of those species were rare. Among these ants, Paratrechina sp.1 and Dolichoderus thoracicus were more aggressive than other species. Ant aggressiveness measured as ant behavioral dominance index (BDI) was positively correlated with ant abundance on the Passiflora species studied. Ant BDI was also positively correlated to the protection that ants provided against herbivory. In Passiflora siamica, the number of workers patrolling on the plants did negatively correlate with average leaf loss per plant. We conclude that in this facultative Passiflora–ant system, plant defense upon herbivore was indeed influenced by the total number of ants present on plant and the aggressiveness of these ants.     

Pluronic F‐68 Enhanced Shoot Regeneration in Micropropagated Citrus Rootstock and Passiflora Species

The promotory effects have been studied of the non‐ionic surfactant, Pluronic F‐68, on bud induction/shoot regeneration in epicotyl and cotyledon explants of Citrus depressa and on shoot regeneration from leaf segments of 4–6 week‐old axenic nodal segment‐derived in vitro plants of Passiflora mollissima, P. giberti and P. edulis var. flavicarpa. For epicotyls of C. depressa, supplementation of agar‐solidified MS‐based bud induction/shoot regeneration medium with 0.5% [w/v] Pluronic F‐68 significantly (P < 0.05) increased mean fresh weight gain of cultures, percentage of explants giving shoots and number of shoots per explant. The same Pluronic concentration also enhanced the mean percentage of cotyledons exhibiting bud induction and the number of buds regenerated per cotyledon explant. Fresh weight gain was unaffected across the range of concentrations (0.001–0.5% w/v) of Pluronic F‐68 evaluated for this latter explant source. For leaf explants from axenic shoot cultures of P. mollissima, supplementation of NN‐based medium, containing 3 mg/l 6‐benzyladenine and 2.0 mg/l kinetin with 0.001–0.5% [w/v] Pluronic F‐68, significantly (P < 0.05) increased mean (± s.e.m.) biomass gain by a maximum of 2.7 ± 0.1 g fresh weight (g f.wt.) over the control. Similarly, for leaf explants of P. giberti, 0.001–0.5% [w/v] Pluronic F‐68 in MS‐based medium, containing 1.0 mg/l 6‐BAP and 0.5 mg/l kinetin significantly (P < 0.05) increased mean percentage of explants undergoing shoot regeneration. For P. edulis leaf explants, mean f.wt. gain was also significantly (P < 0.05) higher with Pluronic F‐68 at 0.001–0.5% [w/v].     

Patterns of herbivory on Passiflora leaf tissues and species by generalized and specialized feeding insects

Abstract.

• 1 The feeding patterns of specialized (Heliconius butterflies) and generalized (the grasshopper, Osmilia flavolineata) herbivores on leaf age classes and species of neotropical vines in the genus Passiflora are compared by offering them leaf discs in choice experiments.
• 2 Heliconius larvae selected young meristematic leaves over medium aged and mature leaves of Passiflora auriculata on which to feed.
• 3 Adults of O. flavolineata consumed more young leaves of P. pittieri from an array of different ages of leaf tissue, but showed no preference for young over mature leaves of P. tetrastylus or P. data.
• 4 In choice tests conducted with medium aged leaves of four species of Passiflora, O. flavolineata selected P. tetrastylus over P. pittieri and P. vitifolia, which were consumed more than P. alata.
• 5 P. alata, which was avoided by O. flavolineata in feeding trials, was the only abundant Passiflora in neotropical habitats where generalized herbivores (grasshoppers and katydids) were common.
• 6 Our results suggest that Passiflora species in forest habitats where some generalized herbivores are rare have fewer chemical defences, but retain physical defences (tough leaves and hooked trichomes) rendering them unpalatable to specialized herbivores like the larvae of Heliconius butterflies.

     

The role of chromosome changes in the diversification of Passiflora L. (Passifloraceae)

Passiflora L. has more than 575 species distributed especially in the Neotropics. The chromosome number variation in the genus is highly congruent with its main subgenera, but its basic chromosome number (x) and the underlying events responsible for this variation have remained controversial. Here, we provide a robust and well-resolved time-calibrated phylogeny that includes 102 taxa, and by means of phylogenetic comparative methods (PCM) we tested the relative importance of polyploidy and dysploidy events to Passiflora karyotype evolution and diversification. Passiflora arose 42.9 Mya, with subgenus diversification at the end of the Palaeogene (Eocene-Oligocene). The basic chromosome number of the genus is proposed as x?=?6, and a strong recent diversification found in the Passiflora subgenus (Miocene) correlated to genome size increase and a chromosome change from n?=?6 to n?=?9 by ascending dysploidy. Polyploidy, conversely, appeared restricted to few lineages, such as Astrophea and Deidamioides subgenera, and did not lead to diversification increases. Our findings suggest that ascending dysploidy provided a great advantage for generating long-term persistent lineages and promoting species diversification. Thus, chromosome numbers/genome size changes may have contributed to morphological/ecological traits that explain the pattern of diversification observed in the genus Passiflora.