Banca de DEFESA: DENIVAL REZENDE QUITERIO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DENIVAL REZENDE QUITERIO
DATE: 22/05/2026
TIME: 10:00
LOCAL: Google meeting: https://meet.google.com/vwp-mbee-ocv
TITLE:

Study of the reproductive phenology of a population of Cereus trigonodendron K. Schum. ex Vaupel (Cactaceae) in the Western Amazon.

KEY WORDS:

reproductive phenophases; climatic fluctuations; flower buds; flowers; fruits

PAGES: 45
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Cereus trigonodendron is a non-endemic species of Cactaceae whose occurrence in Brazil is limited to the state of Rondônia (RO). This succulent grows on rocky outcrops and bears flowers and fruits that are yellow, pink, and red, respectively. The objective of this study was to evaluate the effect of climatic and seasonal variables on the reproductive phenology of this species. Monitoring of flower and fruit production was carried out from May 2022 to May 2025. Observations were divided into reproductive phenophases: (1) flower bud, (2) open flower, (3) immature fruit, and (4) mature fruit. The environmental (abiotic) factors evaluated were: (1) precipitation (PREP); (2) mean maximum temperature (TMM); (3) development time (week_num); and (4) interaction (prep × week_num). Statistical analyses were performed using the R statistical software, including linear regression and correlation tests to assess the effects of abiotic variables—temperature (temp) and precipitation (prep)—together with the biotic factors of the reproductive phenophases, considering a p-value significance level of 5% (p < 0.05). During weekly monitoring, the data indicated that for each phenological development phase, flower buds appeared in the third week, with a peak of 634 buds produced in the fourth week, followed by the flowering stage with a peak of 447 flowers in the sixth week. The subsequent phases were immature fruits, with a peak of 196 in the eleventh week, and in the fourteenth week there was a peak of mature fruits with 94 fruits. The transition from flower buds to the flowering stage was 70.5%. The transition from flowers to immature fruits had a rate of 43.8% of fruits formed, and in the final stage there was a survival rate of about 48% of fruits that either did not mature or were not predated. There was a correlation between precipitation and time (weeks) for the production of immature fruits and fruit maturation. Time was the variable most strongly related to the reproductive phenophases, while temperature showed no relationship, as it remained relatively constant. In the monthly analysis, a total of 770 fruits were produced (monthly mean = 64; median = 54). In the second cycle, 1,296 fruits were recorded (mean production = 107/month; median = 80 fruits). It was observed that the reproductive phenophases of Cereus trigonodendron followed a seasonal pattern, varying according to seasonal climatic fluctuations. The flowers exhibited nocturnal anthesis and reached up to 27 cm in length, while the fruits reached up to 12 cm in length.

COMMITTEE MEMBERS:
Presidente - 1223767 - ANTONIO LAFFAYETE PIRES DA SILVEIRA
Interna - 1822046 - ELISABETE LOURDES DO NASCIMENTO
Externo à Instituição - SEMIRIAN CAMPOS AMOÊDO