Passiflora species presents a coevolutive relationship with Heliconiini butterflies, their primary herbivores. The Heliconiini caterpillars are able to detoxify toxic compounds produced by Passiflora, thus morphologic...Passiflora species presents a coevolutive relationship with Heliconiini butterflies, their primary herbivores. The Heliconiini caterpillars are able to detoxify toxic compounds produced by Passiflora, thus morphological defense strategies stand out over chemical innovations. In this framework, we highlight the presence of mimetic structures and extrafloral nectaries (EFN) as morphological strategies. Heliconian butterflies oviposit only on leaves that do not possess previous eggs, so the presence of egg mimics could prevent the oviposition. EFN are glands that offer nectar to territorial and aggressive ants, establishing mutualistic relationships. Here, we present a structural and chemical analysis of petiolar EFN and nectar from Passiflora alata and P. edulis in order to have insights about the implications of these features in deterring heliconian caterpillars. P. alata have one to four stipitate-crateriform EFN while P. edulis possess a pair of convex glands. Butterflies lay their eggs isolatedly or in up to three on leaves of both species. Our morphological results suggest that EFN from P. alata may act as egg mimics. Ontogenetic data suggest that the variation in the number of glands observed in this species is a serial homology, wherein the selection pressure for this variation is possibly the oviposition pattern. P. alata retain alkaloids, flavonoids and terpenoids inside nectariferous cells;sugars and flavonoids are found in the nectar of both species, while alkaloids are also detected in P. edulis. There is a selective retention/release of secondary metabolites from the EFN tissues to nectar. Knowing that these compounds can be dissuasive to some herbivores and inoffensive to others, we plotted this relationship in a consumer growth versus secondary metabolite concentration diagram. Our results suggest a more active role in the modulation of the gland defense from plants besides the establishment of a mutualistic relationship with ants, an important response in a coevolutive scenario.展开更多
Breeding programs have sought to determine the minimum period of genotype evaluation, which is a long term-process. The objective of this work was to determine the association between qualitative traits of yellow pass...Breeding programs have sought to determine the minimum period of genotype evaluation, which is a long term-process. The objective of this work was to determine the association between qualitative traits of yellow passion fruit (Passiflora edulis Sims) and relate maturity to other characteristics. To carry out this work, 113 families of full-sibs and half-sibs were planted in Viçosa (MG), Brazil, in a randomized block experimental design arranged in sets (treatment groups). The association between the analyzed characteristics was studied using path analysis and canonical correlation techniques. It was found that lower-yielding but larger-fruit bearing genotypes of passion fruit plant also require more days until reaching anthesis. Round-shaped fruits are linked to higher contents of total soluble solids. More intense pulp color also indicates higher contents of total soluble solids. The riper the fruit, the more intensely orange is the color of the pulp. The ratio between the levels of total soluble solids and total titrimetric acidity was the main determinant of pulp color for passion fruit.展开更多
基金supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq 131813/2008-0).
文摘Passiflora species presents a coevolutive relationship with Heliconiini butterflies, their primary herbivores. The Heliconiini caterpillars are able to detoxify toxic compounds produced by Passiflora, thus morphological defense strategies stand out over chemical innovations. In this framework, we highlight the presence of mimetic structures and extrafloral nectaries (EFN) as morphological strategies. Heliconian butterflies oviposit only on leaves that do not possess previous eggs, so the presence of egg mimics could prevent the oviposition. EFN are glands that offer nectar to territorial and aggressive ants, establishing mutualistic relationships. Here, we present a structural and chemical analysis of petiolar EFN and nectar from Passiflora alata and P. edulis in order to have insights about the implications of these features in deterring heliconian caterpillars. P. alata have one to four stipitate-crateriform EFN while P. edulis possess a pair of convex glands. Butterflies lay their eggs isolatedly or in up to three on leaves of both species. Our morphological results suggest that EFN from P. alata may act as egg mimics. Ontogenetic data suggest that the variation in the number of glands observed in this species is a serial homology, wherein the selection pressure for this variation is possibly the oviposition pattern. P. alata retain alkaloids, flavonoids and terpenoids inside nectariferous cells;sugars and flavonoids are found in the nectar of both species, while alkaloids are also detected in P. edulis. There is a selective retention/release of secondary metabolites from the EFN tissues to nectar. Knowing that these compounds can be dissuasive to some herbivores and inoffensive to others, we plotted this relationship in a consumer growth versus secondary metabolite concentration diagram. Our results suggest a more active role in the modulation of the gland defense from plants besides the establishment of a mutualistic relationship with ants, an important response in a coevolutive scenario.
文摘Breeding programs have sought to determine the minimum period of genotype evaluation, which is a long term-process. The objective of this work was to determine the association between qualitative traits of yellow passion fruit (Passiflora edulis Sims) and relate maturity to other characteristics. To carry out this work, 113 families of full-sibs and half-sibs were planted in Viçosa (MG), Brazil, in a randomized block experimental design arranged in sets (treatment groups). The association between the analyzed characteristics was studied using path analysis and canonical correlation techniques. It was found that lower-yielding but larger-fruit bearing genotypes of passion fruit plant also require more days until reaching anthesis. Round-shaped fruits are linked to higher contents of total soluble solids. More intense pulp color also indicates higher contents of total soluble solids. The riper the fruit, the more intensely orange is the color of the pulp. The ratio between the levels of total soluble solids and total titrimetric acidity was the main determinant of pulp color for passion fruit.
