Banca de DEFESA: HEDINA BASILE BEZERRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : HEDINA BASILE BEZERRA
DATE: 31/01/2022
TIME: 14:00
LOCAL: Plataforma Google Meet: http://lattes.cnpq.br/9195020852035418
TITLE:

In vitro propagation of Rodriguezia venusta (Lindl.) Rchb.f. (Orchidaceae), ornamental species threatened with extinction.

KEY WORDS:

Plant Tissue Culture; Shooting; Survival; Growth regulators.

PAGES: 60
BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Fisiologia Vegetal
SUMMARY:

Rodriguezia venusta (Lindl.) Rchb.f. is an epiphyte orchic native to South America, that even though its abundance in rain forests such as Atlantic Forest, it is in risk of extinction due to indiscriminate collection. Aiming for a more efficient alternative of production of plants other than conventional methods such as natural shooting or multiplication through seeds, in vitro propagation stands for the possibility of fast and large-scale production of plants. Thus, the objective of this study was to develop a protocol for in vitro propagation of R. venusta aiming the supply of seedlings for the ornamental market, consequently contributing to the preservation of the species. For such purpose, whole plants measuring 0.5-1.5 cm were used as explants, that were previously germinated in vitro. The break of apical dominance was achieved through a longitudinal incision made from the apix to the base of each plantlet. The explants were cultivated in nutritive media MS/2, added with 15 g/L of sucrose and 2 g/L of activated charcoal, containing NAA or 2,4D (0,0; 2,5 or 5,0 μM/L) combined with BAP or KIN (0,0; 5,0 or 10 μM/L). On the propagation of the first clonal generation (F1), the variables occurrence of oxidation, survival, callogenesis, response to shooting, direct, indirect, and total shooting for the tested treatments were evaluated in a cultivation period of 16 weeks. The shoots obtained were kept in nutritive medium MS/2 for, at least, 30 days for better growth and development before use in the next step of propagation. In the propagation of F1, significative interactions between the treatments tested and the variables survival, direct, indirect, and total shooting were observed. The other variables seemed to be influenced only by the cultivation time. Based on the performance of shooting and least financial cost, the treatments control (absence of growth regulators) and the one containing 2.4D 5.0 μM/L + KIN 10 μM/L were selected for the propagation of the second clonal generation (F2), treatments that presented shooting averages of 10.50 and 7.60 shoots/explant respectively by the end of 16 weeks. The propagation of F2 was evaluated along 28 weeks. Significative interactions between the treatments used and the variables survival, indirect and total shooting were observed. The other variables were influenced only by the cultivation time. The treatment containing growth regulators presented a survival rate reduction from the eighth cultivation week (63%), ending the 28 weeks of cultivation with 54% of survival, a rate statistically lower than the one observed in the control (87%). Despite that, the treament with growth regulators presented a shooting average of 11,23 shoots/explant, overcoming the average of 6,87 shoots/explant observed in the control treatment by the end of 28 cultivation weeks, and then compensating the reduction on survival by the high shooting rate produced. Thus, it is suggested to use both treatments control and 2,4D 5,0 μM/L + KIN 10,0 μM/L in the continuity of the in vitro propagation, to be performed for a minimum cultivation time of 12 weeks for callogenesis induction, and 16 weeks for the begginging of shooting response, aiming to verify the performance of both protocols in multiple subcultures for the best cost/benefit relationship in the propagation of R. venusta.

BANKING MEMBERS:
Presidente - 1299193 - ALESSANDRA SELBACH SCHNADELBACH
Externa à Instituição - ALONE LIMA BRITO - UEFS
Externa à Instituição - MARIA NAZARE GUIMARAES MARCHI - IFBaiano