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| Author(s): |
Guaraci Duran Cordeiro
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2015-03-06 |
| Examining board members: |
Isabel Alves dos Santos;
Márcia Motta Maués;
Leonor Patrícia Cerdeira Morellato;
Clemens Peter Schlindwein;
Cláudia Inês da Silva
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| Advisor: | Isabel Alves dos Santos |
| Abstract | |
The family Myrtaceae has many fruiting species, some are commercially explored. Among those species is the cambuci (Campomanesia phaea). The objectives this work were to describe the reproductive phenology, the floral biology, the reproductive system, and to identify the pollinators of cambuci in order to generate new knowledge that may help increase the productivity of this species. The study about reproductive phenology was conducted for two years, in an area of natural occurrence and in a commercial crop. The phenophases (flowering and fruit set) were monitored with Activity index (synchrony) and Intensity index (Fournier intensity) and correlated with abiotic factors (temperature, rainfall, and day length). The results showed that flowering and fruit set of C. phaea in natural area and crop were different even under same climatic conditions. The flowering and fruit set were more intense and synchrony in the crop. The abioctic factors do not explain these differences in the phenophases between the study areas, but other variables, such as soil fertilization and pollinator diversity, play an important role. In the pollination study of C. phaea were observed the anthesis duration, floral resources, stigma receptivity, and pollen viability. The reproductive system of C. phaea was investigated based on the P:O ratio and by carrying out manual pollination tests. The flower visitors were captured and determined the most efficient pollinators, according to effectiveness by number of pollen grains deposited in the stigma and number of fruit set. The flowers of C. phaea last two days, are hermaphrodite, and have pollen as the only resource offered to flower visitors. Its anthesis is nocturnal and begins around 5 h. The reproductive system of C. phaea is self-incompatible. Were collected 52 species of flower visitors and among them the most efficient in pollination were nocturnal and crepuscular bees (Megalopta sodalis, Megommation insigne, Ptiloglossa latecalcarata e Zikanapis seabrai). Besides these bees, the flowers of C. phaea flowers were also visited and pollinated by Apis mellifera in crepuscular and diurnal periods. In order to understand how the nocturnal/crepuscular bees find cambuci flowers in darkness flower volatiles were collected (at night and during the day) by dynamic headspace method and after analyzed by GC-MS. In addition, electroantennographic (GC-EAD) and behavioural experiments (bioassays) were performed to test if compounds identified from cambuci flowers are capable in eliciting electrophysiological and behavioural responses in nocturnal/crepuscular bees. In total 14 volatiles compounds were found in C. phaea flowers, the same in the night and day samples. Although, the relative scent composition differed between these two periods. The volatile emission is higher during the activity of nocturnal/crepuscular bees, and some compounds are more eminent during the night (e.g., 1-Octanol) and some during the day (e.g., 2-Phenylethanol). The nocturnal/crepuscular were attracted by synthetic scent of the cambuci flowers. Apis mellifera also showed positive responds towards for electroantennographic and behavioural bioassays. The results showed that volatiles emitted at night by C. phaea flowers have attractive function to nocturnal/crepuscular bees, and suggest that 1-Octanol can be the key compound for this attraction. (AU) | |
| FAPESP's process: | 11/06811-5 - Phenology, reproductive biology and pollination of cambuci (Campomanesia phaea - Myrtaceae) and monitoring of associated apifauna |
| Grantee: | Guaraci Duran Cordeiro |
| Support Opportunities: | Scholarships in Brazil - Doctorate |