Vasconcellea species, often referred to as highland papayas, are wild relatives of common papaya (Carica papaya) widely distributed in tropical America, with a preference for cooler climates. The genus deserves special attention as its species show potential as raw materials in the tropical fruit industry, papain source or as genetic resources in breeding programs of C. papaya. However, studies related to breeding system and pollination biology of genus are still unexplored. We characterize the reproductive biology of dioecious Vasconcellea quercifolia, one of the southernmost Caricaceae. According to floral shape and presence of nectar, we expected that this species had a specializated pollination system, with moths as the primary pollinators. To test this, we studied floral biology, floral visitors, pollinators, and breeding system of this species. Controlled pollination experiments show that V. quercifolia is a xenogamous species that depends on its pollinators to set fruits (18 and 79 % fruit and seed set under open-pollination, respectively). Anemophily and apomixis occur very seldom. The treatments of exclusion of floral visitors and pollen load analysis showed that the main pollinators are moths belonging to Arctiidae, Noctuidae, and Pyralidae. The only reward for pollinators is the nectar produced by male flowers. Female flowers are pollinated by deceit because they do not produce floral rewards.

A phytochemical study of Senecio iodanthus and Senecio bracteatus afforded the new pyrrolizidine alkaloid iodanthine (3) in addition to the four known alkaloids retroisosenine (1), bulgarsenine (2), mulgediifoliine (4), and (12S)-12-hydroxyretroisosenine (6). The structure and absolute stereochemistry of the new compound (3) were determined by its spectral properties and confirmed by an X-ray diffraction analysis.

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Summary:Reproductive system of Trichloris (Poaceae, Chloridoideae, Chlorideae). Trichloris crinita and T. pluriflora are important native forage species with the potential to be domesticated and introduced to cultivation, but there is scarce basic information on their reproductive biology. The aim of this work was to determine the reproductive system of both plant species in populations coming from north-central Argentina. The following was proposed: 1) determine the reproductive system through the fruit/flower ratio under controlled pollination, 2) quantify the weight of the fruits produced by population under different treatments and 3) confirm or discard the presence of apomixis through embryological observations. In T. crinita, the average fruit/flower ratio was 92.4 ± 6.6%, while in T. pluriflora, it was 70.7 ± 9.9%. These results are consistent with self-compatible species, preferably self-pollinated ones. Embryo sac development indicates sexual origin of seeds in both species. Significant differences in the average weight of one hundred fruits among populations and treatments, in both species, were found. The fruits were lighter in self-pollination. The information presented is a contribution to the tasks of selection and introduction to the culture of both species as well as to the conservation and regeneration of the collected germplasm.Key words: Trichloris, Reproductive success, Self-pollination, Fruit weight.Resumen: Trichloris crinita y T. pluriflora constituyen importantes forrajeras nativas con potencialidades de ser domesticadas e introducidas al cultivo, pero es escasa la información básica sobre su biología reproductiva. El objetivo de este trabajo fue determinar el sistema reproductivo de ambas especies en poblaciones provenientes del centro-norte de Argentina. Se propuso: 1) establecer el sistema reproductivo a través de la relación fruto/flor en polinizaciones controladas, 2) cuantificar el peso de los frutos producidos, por población, bajo diferentes tratamientos y, 3) confirmar o descartar la presencia de apomixis a través de observaciones embriológicas. En T. crinita, la relación fruto/flor promedio fue de 92,4 ± 6,6%, mientras que en T. pluriflora, fue de 70,7 ± 9,9%. Estos resultados se corresponden con especies autocompatibles, preferentemente autógamas. El desarrollo del saco embrionario indica origen sexual de las semillas en ambas especies. Se hallaron diferencias significativas en el peso promedio de cien cariopsis entre poblaciones y entre tratamientos, en ambas especies. Los frutos fueron más livianos en autopolinización. La información que se presenta es un aporte a las tareas de selección e introducción al cultivo como también a la conservación y regeneración del germoplasma recolectado.Palabras clave: Trichloris, Éxito reproductivo, Autopolinización, Peso de frutos.

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