Secretory trichomes, a substitutive floral nectar source in Lundia A. DC. (Bignoniaceae), a genus lacking a functional disc.
This is the first report of corolla-borne secretory trichomes that substitute in role for a non-functional disc in a species of the neotropical genus Lundia A. DC. (Bignoniaceae). The floral biology and flowering phenology of Lundia cordata were investigated at two remnants of tropical rainforest in northeastern Brazil. This species is a typically omithophilous liana, with reddish, tubular, scentless flowers. The flowers are resupinate, protandrous and last for 2 d. There is a vestigial non-functional perigynous disc and nectar is secreted by glandular trichomes distributed along the internal surface of the corolla. The nectar is stored at the base of the corolla tube, thus showing secondary nectar presentation. The nectariferous trichomes are multi-cellular, uniseriate, with a basal foot cell rooting in the epidermis, one neck cell, and a glandular head with 13 cells on average. Three species of hummingbirds (Amazilia fimbriata, Eupetomena macroura and Phaethornis pretrei) serve as pollinators. Phaethornis ruber, Xylocopa bees, wasps and diurnal moths are considered nectar thieves. (+info)
Histological study of post-pollination events in Spathodea campanulata beauv. (Bignoniaceae), a species with late-acting self-incompatibility.
The reproductive biology of Spathodea campanulata was investigated by means of hand-pollination experiments, observations of pollen tube growth using fluorescence microscopy, and serial sections of ovules in selfed and crossed pistils. Only cross-pollinated flowers developed fruits, and all selfed flowers abscised within 3-4 d. However, self pollen tubes grew successfully to the ovary, penetrating and fertilizing the majority of ovules by 48 h, indicating that S. campanulata is a species with late-acting self-incompatibility. The incidences of ovule penetration, fertilization and endosperm initiation were all significantly slower in selfed vs. crossed pistils, although no other signs of malfunctioning were detected. The possible role of such slow self pollen tube effectiveness as a recognition event is discussed within the context of the slow but not entirely suppressed self pollen tube growth reported for some species with conventional homomorphic self-incompatibility. (+info)
The north-east-Brazilian Liana, Adenocalymna dichilum (Bignoniaceae) pollinated by bats.
BACKGROUND AND AIMS: Of the set of syndromes displayed by specialized (euphilic) flowers, adaptation to pollination by bats (chiropterophily) is the least known. Accumulated new evidence reveals that this pollination mode plays a considerable role in tropical communities, especially in the neotropics. One family in which bat-pollinated species are known in several genera is the Bignoniaceae. Here is reported, for the first time, bat pollination and floral ecology in Adenocalymna dichilum (tribe Bignonieae). METHODS: Floral features of this species growing in Bahia (north-east Brazil) indicated possible chiropterophily, which was subsequently confirmed by direct observation and from photographs of bat visits. Timing of anthesis and nectar parameters were monitored in the field, and floral morphology was investigated with fixed flowers. KEY RESULTS: One to two flowers open per night on the upright, simple racemes of A. dichilum during several weeks in a 'steady state' mode. The bilabiate, cream-coloured corollas are functional for only a single night and wilt during the following day. A stout corolla, with a musky odour, and a large nectary disc with large quantities of watery nectar also conform to the syndrome. Glossophaga soricina (Glossophaginae) visited and pollinated the flowers in a trap-lining manner. Whilst hovering, the bats put their heads into the corolla mouth for less than 1 s to feed, thereby effecting the transfer of pollen which is deposited on their backs. CONCLUSIONS: Adenocalymna, a New World genus comprising approx. 50 species, exhibits floral adaptive radiation including species pollinated by bees, birds and possibly moths. The discovery of chiropterophily in A. dichilum adds another facet to the array of floral syndromes represented in the genus. (+info)
Studies on the constituents of Catalpa species. IX. Iridoids from the fallen leaves of Catalpa ovata G. Don.
Two new iridoids, 6-O-trans-p-coumaroyl-7-deoxyrehmaglutin A (1) and 6-O-cis-p-coumaroyl-7-deoxyrehmaglutin A (2), were isolated from the fallen leaves of Catalpa ovata G. DON. together with six artifact iridoids (3-8). Their structures were established by spectral analysis. In addition, the scavenging effects of the principal compounds isolated from this plant on 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity were examined. (+info)
Phloem loading. A reevaluation of the relationship between plasmodesmatal frequencies and loading strategies.
The incidence of plasmodesmata in the minor vein phloem of leaves varies widely between species. On this basis, two pathways of phloem loading have been proposed: symplastic where frequencies are high, and apoplastic where they are low. However, putative symplastic-loading species fall into at least two categories. In one, the plants translocate raffinose-family oligosaccharides (RFOs). In the other, the primary sugar in the phloem sap is sucrose (Suc). While a thermodynamically feasible mechanism of symplastic loading has been postulated for species that transport RFOs, no such mechanism is known for Suc transporters. We used p-chloromercuribenzenesulfonic acid inhibition of apoplastic loading to distinguish between the two pathways in three species that have abundant minor vein plasmodesmata and are therefore putative symplastic loaders. Clethra barbinervis and Liquidambar styraciflua transport Suc, while Catalpa speciosa transports RFOs. The results indicate that, contrary to the hypothesis that all species with abundant minor vein plasmodesmata load symplastically, C. barbinervis and L. styraciflua load from the apoplast. C. speciosa, being an RFO transporter, loads from the symplast, as expected. Data from these three species, and from the literature, also indicate that plants with abundant plasmodesmata in the minor vein phloem have abundant plasmodesmata between mesophyll cells. Thus, plasmodesmatal frequencies in the minor veins may be a reflection of overall frequencies in the lamina and may have limited relevance to phloem loading. We suggest that symplastic loading is restricted to plants that translocate oligosaccharides larger than Suc, such as RFOs, and that other plants, no matter how many plasmodesmata they have in the minor vein phloem, load via the apoplast. (+info)
Newbouldiaquinone and newbouldiamide: a new naphthoquinone-anthraquinone coupled pigment and a new ceramide from Newbouldia laevis.
Newbouldiaquinone (1), a new naphthoquinone-anthraquinone coupled pigment and a new ceramide named newbouldiamide (2), have been isolated from Newbouldia laevis, besides the known compounds lapachol (3), canthic acid, oleanolic acid, 2-methyl-9,10-anthracenedione, 2-acetylfuro-1,4-naphthoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-(4-hydroxyphenyl)ethyl triacontanoate, beta-sitosterol and beta-sitosterol glucopyranoside. The structure elucidations of the isolated new compounds were performed on the basis of spectroscopic and chemical evidence. Preliminary studies showed that 1 is moderately antibacterial against Gram-positive Bacillus megaterium and that 3 has moderate herbicidal and antibacterial activities. (+info)
A monoterpene alkaloid from incarvillea sinensis.
A novel monoterpene alkaloid, named incarvillateine E, possessing three moles of incarvilline moieties, has been obtained from the aerial parts of Incarvillea sinensis LAM. (Bignoniaceae). On the basis of spectroscopic evidence, the structure of incarvillateine E has been characterized. (+info)
Pharmacological study on the novel antinociceptive agent, a novel monoterpene alkaloid from Incarvillea sinensis.
To determine the antinociceptive mechanism of incarvillateine (INCA), the opiate antagonists nor-binaltorphimine (nor-BNI), beta-funaltrexamine (beta-FNA) and naltrindole (NTI) were pretreated prior to its injection in a formalin test. The antinociceptive effect of INCA was antagonized by nor-BNI (kappa-receptor antagonist) and beta-FNA (mu-receptor antagonist), while NTI (delta-receptor antagonist) did not influence its effect. Furthermore, the antinociceptive effect of INCA was blocked by theophylline (THEO), an adenosine-receptor antagonist. These results suggested that the antinociceptive effect arose from the activation of mu-, kappa-receptors and adenosine-receptor. (+info)