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| Author(s): |
Everton Hilo de Souza
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) |
| Defense date: | 2013-11-28 |
| Examining board members: |
Adriana Pinheiro Martinelli;
Maria Angélica Pereira de Carvalho Costa;
Giancarlo Conde Xavier Oliveira;
Marlies Sazima;
Leonardo de Melo Versieux
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| Advisor: | Adriana Pinheiro Martinelli; Fernanda Vidigal Duarte Souza |
| Abstract | |
Bromeliads are tropical ornamental plants with a wide variety of colors and shapes that make them widely and extremely appreciated. The study of aspects of the floral biology, associated with the reproductive systems of these species are of fundamental importance for breeding and species conservation programs, assisting in the determination of the degree of compatibility between combination of genotypes, as well as potential reproductive barriers. The aim of this research is to study aspects of floral and reproductive biology, conservation of pollen grains, studies of volatile compounds in flowers and intergeneric and interspecific hybridization in Bromeliaceae with ornamental potential. High genetic variability was observed among the species studied, regarding the morphology of the pollen grains and stigma. High rates of germination and pollen viability were observed for the different species, and stigma receptivity showed the highest at anthesis. These characteristics are of great importance for fertilization and further seed production, thus are essential for the production of hybrids and species conservation. Preservation of pollen grains, showed the best results with a 3 h dehydration pre-treatment in silica and conservation in liquid nitrogen (-196°C). A large number of volatile compounds, totally 71, were identified from flowers of thirteen species. Some of these compounds have already been shown to be important in the food industry, cosmetics, perfumes, chemical and pharmaceutical industry. Among the seventeen species, more than 50% presented selfincompatibility and some species presented autogamy, demonstrating that these species present spontaneous self-pollination. Agamospermy was observed in only two species. Ninety-five combinations among 17 species of Aechmea and Ananas (Bromelioideae) and Alcantarea and Vriesea (Tillandsioideae) were performed, with a 33.74% rate of success, with 24.96% involving the botanical varieties of Ananas. Only two, among the intergeneric combinations, were successful, V. michaelii x Al nahoumii and V. simplex x Al nahoumii. Possible causes of self-incompatibility and incongruity in these combinations were related to different events during pollen tube growth, such as the irregular deposition of callose in pollen tubes; entangled pollen tubes in the style; arrest of pollen tube growth in the style, among others. We suggest that the self-incompatibility is gametophytic, preventing selffertilization. Further studies will help to characterize the causes and potential measures to overcome self-incompatibility. The results provide important contributions to studies of hybridization in bromeliads, aiming to produce new hybrids for the ornamental plants market, as well as contributions to the characterization and conservation of this important family of plants (AU) | |
| FAPESP's process: | 09/18255-0 - Reproductive develpment and interespecific and intergeneric hibridization in bromeliads with ornamental potential |
| Grantee: | Everton Hilo de Souza |
| Support Opportunities: | Scholarships in Brazil - Doctorate |