Banca de QUALIFICAÇÃO: ELLEN MARIA GOMES SUZANO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELLEN MARIA GOMES SUZANO
DATE: 30/09/2025
TIME: 13:00
LOCAL: Instituto de Agronomia
TITLE:

SALICYLIC ACID AND SODIUM NITROPRUSSIATE AS SALINE STRESS MITIGATORS IN THE GERMINATION OF ORNAMENTAL PLANT SEEDS.

KEY WORDS:

Saline stress; Seed priming; Physiological quality; Ornamental seeds

PAGES: 49
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SUMMARY:

Salinity is one of the main abiotic factors that limits the growth and quality of ornamental plants, reducing their commercial value and causing losses to the sector. Seed germination is the most sensitive phase to this stress, as excess salts hinder water absorption and trigger physiological imbalances. As a mitigation strategy, pre-germination (priming) treatments with salicylic acid (SA) and sodium nitroprusside (SNP) have been explored. SA acts as a growth regulator associated with stress tolerance, while SNP is used as a donor of nitric oxide (NO), a signaling molecule involved in regulating adaptive responses. However, their mechanisms of action are not yet fully understood, which reinforces the need for further research. In this context, the general objective of this study is to evaluate the effect of SA and SNP application on the physiological quality of seeds and the morphology of seedlings of different ornamental species. Commercial seeds of the species Tagetes patula L., Impatiens balsamina L., Zinnia elegans L., and Phlox drummondii Hook will be used as study objects in this project. The experimental design will be completely randomized in a 3 (salinity levels: 0 mg L-1 (control), 50 mg L-1 (low salinity), and 150 mg L-1 (high salinity)) x 3 factorial scheme (priming conditions: 1.0 mM salicylic acid, 0.2 mM sodium nitroprusside, and distilled water) with four replicates and 50 seeds per plot. The seeds will be treated (for a period of 24 hours) with three types of priming and then placed to germinate in the different saline solutions in a B.O.D. chamber under temperature and light conditions, as recommended for each ornamental species by the Rules for Seed Analysis (RAS). All species will be subjected to the same treatments, but studied individually in experiments due to their specific germination characteristics and seedling morphologies. Evaluations will be performed daily until the last germination count indicated by the RAS. At the end of the test, the percentage of normal, abnormal, and dead seedlings will be counted. The percentage of germinated plants in the first and final germination counts will be calculated, as well as the Germination Speed Index (GSI). After the final count, root length, hypocotyl length, and seedling fresh and dry mass values will be obtained. Data will be subjected to analysis of variance (ANOVA) at a 5% significance level. When significant differences are identified, treatment means will be compared using appropriate comparison tests, also at a 5% probability level. The aim is to understand how salt stress influences the germination and seed vigor of the ornamental species studied, as well as its influence on seedling morphology. And to evaluate the efficiency of priming with AS and SNP in mitigating the adverse effects of salinity.

COMMITTEE MEMBERS:
Presidente - 2379124 - ROGERIO GOMES PEGO
Externa ao Programa - 1724645 - CIBELLE VILELA ANDRADE FIORINI - UFRRJExterna à Instituição - MICHELE CAGNIN VICENTE - FAETEC