Banca de DEFESA: KARLA EMANUELLE CAMPOS ARAUJO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : KARLA EMANUELLE CAMPOS ARAUJO
DATA : 24/08/2018
HORA: 13:00
LOCAL: sala 1
TÍTULO:

Estimation of amount of nitrogen accumulated into the soil by the Soybean Radicular System Using ¹⁵N-labeled Urea and Glutamine as source of ¹⁵N

PALAVRAS-CHAVES:

 15N Isotopic dilution, BNF, Leaf label with 15N.

PÁGINAS: 65
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

The objective of this study was to evaluate the use of the isotopic technique ^(15N leaf marking) to estimate the total N accumulated in the soybean root system. The experiment was conducted in pots of 6 kg soil, in greenhouse at Embrapa Agrobiologia, Seropédica, RJ. The experimental design was a randomized complete block design with five replicate plots. The treatments consisted of ¹⁵N-leaf marking using two N sources, ¹⁵N-Urea and ¹⁵N-glutamine, and six collection times, which were performed at 2, 7, 14, 25, 47 and 70 days after labeling with the isotope ¹⁵N, corresponding to the stages V4, R1, R3, R5, R6 and R7, respectively. The enrichment of ¹⁵N in the tissue of the plant in each collection and the nitrogen in the unrecovered roots-NRnr (in the rizosferic soil and in the total soil of the vessels) was determined. The ¹⁵N enrichment data of the different root segments of the plants showed uniformity at the 10 and 14 DAM marking of the ¹⁵N supply through the leaves for both urea and glutamine. At 45 DAM, the roots marked with glutamine remained uniform, in contrast the roots marked with urea presented significant differences between them. The enrichment data of ¹⁵N of the different aerial part segments of the plants showed that there was no uniformity in the marking between the parts of the plant, for the collections performed at 2, 7, 10 DAM. In general, glutamine-labeled plants showed a slower label distribution throughout the plant. Regarding the contributions of NRnr (mg / plant), it was observed that in the 2 DA of the plants there was a large exudation of the N, between 163 mg and 141 mg, for the urea and glutamine treatments, respectively. For the NRnr (%) it was observed that for the two sources of marking from the 10 DAM of the plants, practically no differences were observed, and, from then on, the NRnr remained uniform, varying from 8 to 15% of N accumulated by whole plant, for the two marking sources. In this unpublished study, we showed that initially (up to 2 AMD) there was an exudation of enriched N. Regardless of the source of N used in the labeling of the plant with 15N, the NRnr did not show large differences, regardless of the source of ¹⁵N-Urea or ¹⁵N-Glutamine marking did not interfere in the estimation of NRnr. In the total N balance of the whole soybean plant, between 11 and 14% of the total N accumulated by the whole plant is in the underground part of the plant.

MEMBROS DA BANCA:
Externo à Instituição - CLAUDIA POZZI JANTALIA - EMBRAPA
Interno - 387256 - JORGE JACOB NETO
Externo à Instituição - MARCIO DOS REIS MARTINS - EMBRAPA
Externo ao Programa - 2136627 - NIVALDO SCHULTZ
Externo ao Programa - 644.889.777-15 - ROBERT MICHAEL BODDEY - OUTRO