Banca de QUALIFICAÇÃO: RUAN PORTIOLLE CARLOS PINHEIRO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RUAN PORTIOLLE CARLOS PINHEIRO
DATE: 23/04/2026
TIME: 09:00
LOCAL: CB- Sala SS1
TITLE:

CALLUS INDUCTION FROM SEEDLINGS OF Piptadenia retusa: A MEDICINAL LEGUME TREE NATIVE TO THE BRAZILIAN CAATINGA

KEY WORDS:

callogenesis, native species, secondary metabolites, Brazilian semi-arid region

 

PAGES: 51
BIG AREA: Ciências Agrárias
AREA: Recursos Florestais e Engenharia Florestal
SUBÁREA: Silvicultura
SPECIALTY: Sementes Florestais
SUMMARY:

Piptadenia retusa is a multiuse woody species from the Caatinga, recommended to
restoration of degraded areas and able to produce secondary metabolites of
pharmacological interest. In this sense, the aim of this work was to establish an
optimized protocol for callus induction from this species. P. retusa seedlings obtained
from aseptic seed germination under controlled conditions (80 µmol m -2 s -1 , 12 h-
photoperiod, and 27  2 C) were used as source of explants. The type of explant (root,
hypocotyl, epicotyl, and leaf), illumination (12 h-photoperiod and continuous darkness),
and growth regulators (2,4-dichlorophenoxiacetic acid and kinetin) were tested on
callus induction. The explants were cultivated on Woody Plant Medium with 2% (w/v)
sucrose and 3% (w/v) Phytagel, pH 5.6, during four weeks under the same conditions.
The experimental design was completely randomized with 15 repetitions for treatment;
factorial design was utilized when necessary. The cultures were weekly evaluated in
terms of callogenesis and oxidation percentage; at the end of the experiments, texture
and colour were observed, and dry weight was determined. Leaf and hypocotyl
segments showed higher percentage of friable callus and dry weight than those of root
and epicotyl at the presence of 10 µM 2,4-dichlorophenoxiacetic acid and 2,5 µM
kinetin, regarding the control. As callus derived from hypocotyl demonstrated extensive
and uniform cell masses, this explant was selected for the next experiments. Under 12
h-photoperiod, hypocotyl segments exposed to 10 µM 2,4-dichlorophenoxiacetic acid
and 2,5 µM kinetin produced callus more frequently, with lower oxidation, a friable
texture and a higher dry weight than the respective control, as well as those grown
under continuous darkness. Increasing concentrations of 2,4-dichlorophenoxiacetic
acid, combined with 2,5 µM kinetin, progressively increased the percentage of callus
induction from hypocotyl segments. Since the highest concentration of auxin tested (15
µM) induced elevated percentage of friable callus coinciding with high dry weight
accumulation, this growing condition is being utilized in the following experiments. After
the determination of the more effective cytokinin concentration, a growth curve will be
carried out during six to eight weeks to determine optimized growing conditions for P.
retusa callus.

 

COMMITTEE MEMBERS:
Presidente - 1228866 - EDUARDO LUIZ VOIGT
Interno - 1721230 - MAURO VASCONCELOS PACHECO
Externa ao Programa - 1516627 - JULIANA ESPADA LICHSTON - UFRN