Banca de QUALIFICAÇÃO: RAQUEL YELLIN CASTAÑEDA VENEGAS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: RAQUEL YELLIN CASTAÑEDA VENEGAS
DATA: 29/08/2024
HORA: 08:30
LOCAL: DBI03 - Anfiteatro do Setor de Fisiologia Vegetal
TÍTULO:

NITROGEN REMOBILISATION IN SACCHARUM SPP (CV. CTC9001BT) UNDER DROUGHT STRESS AND REHYDRATION CONDITIONS

PALAVRAS-CHAVES:

Sugarcane, drought stress, nitrogen mobilisation, nutrient remobilisation, rehydration

PÁGINAS: 30
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
RESUMO:

Drought stress is an important environmental constraint in sugarcane production in Brazil, and
one-way plants adapt to this stress is by upregulation of their nutrient remobilisation. In this
study, a greenhouse experiment was carried out to examine the effects of water availability on
nitrogen mobilization in sugarcane (Cv. CTC9001bt). At 25 days after transplanting (DAT), the
+1 leaf was labeled with ammonium sulphate ([NH 4] 2 SO 4 ) enriched to 10% atom of 15 N. At 27
DAT two water treatment regimes were applied: stress (S, 20%FC) and hydrated (H, 100%FC),
laid out in a completely randomized design. Data were collected at two different time points that
corresponded to maximum stress of the dehydrated plants (38 DAT) and after rehydration (43
DAT). For the analysis of isotopic composition using an isotope ratio mass spectrometer
(IRMS), root, stem, and leaf sheath were collected and oven-dried at 55°C for 3 days.
At maximum stress, the nitrogen content was higher in the leaf sheath and stem of S plants
(12.1% and 6.0%) compared to H plants (4.7% and 4.2%), while the roots did not show
differences. Following rehydration, higher nitrogen recovery (14.6%) was observed in the stems
of S plants, likely remobilised from sheath leaves, which showed a reduction of 44% compared
to when at maximum stress. The accumulation of dry matter in roots of S plants slightly
increased at maximum stress. After rehydration, the accumulation of dry matter in the stems
and roots of S plants was higher (+43% and +29%) compared to H plants. These findings
suggest during stress sugarcane prioritises nitrogen mobilisation to sheath leaves, redistributing
it to the stem upon rehydration. Increased root biomass under stress and rehydration indicates
improved water and nutrient uptake, supporting plant resilience.

MEMBROS DA BANCA:
Interno - VITOR DE LAIA NASCIMENTO (Membro)
Presidente - PAULO EDUARDO RIBEIRO MARCHIORI (Membro)
Externo ao Programa - MARIA LIGIA DE SOUZA SILVA - DCS/ESAL (Membro)
Externo à Instituição - EDUARDO MARIANO - USP (Suplente)
Interno - DINORAH MORAES DE SOUZA MARÇAL - UFV (Suplente)
Interno - DANIEL AMORIM VIEIRA - UFLA (Membro)