ECOPHYSIOLOGICAL ASPECTS OF PRODUCTION OF Melanoxylon brauna SCHOTT SEEDLINGS
Name: INGRIDH MEDEIROS SIMÕES
Publication date: 27/02/2025
Examining board:
Name |
Role |
|---|---|
| HELOISA OLIVEIRA DOS SANTOS | Examinador Externo |
| JOSE EDUARDO MACEDO PEZZOPANE | Examinador Interno |
| KHETRIN SILVA MACIEL | Examinador Externo |
| RODRIGO SOBREIRA ALEXANDRE | Presidente |
| WILSON VICENTE SOUZA PEREIRA | Examinador Externo |
Summary: Melanoxylon brauna Schott, known as braúna, is a native species of the Atlantic Forest and is threatened with extinction due to intense logging and low natural regeneration rates. Propagation by seeds is hampered by low viability and predation, in addition to high mortality of seedlings in nurseries, caused by factors such as excess water and inadequate substrates. This study aimed to evaluate the survival, morphophysiological and biochemical growth of M. brauna seedlings produced from seeds collected in different locations and grown in different combinations of soils and substrates, as well as to analyze their adaptation mechanisms to water and heat stress. The results demonstrated that the soil collected close to the mother trees (100%) provided the highest survival rates (97.5% and 90%) and better seedling quality, regardless of the origin of the seeds. This soil also showed a higher presence of fungal spores, especially arbuscular mycorrhizal fungi such as Glomus macrocarpum, Sclerocytis spp. and Gigaspora spp., suggesting a symbiotic relationship essential for seedling development. Enzyme activity (APX, CAT, POD and SOD) was higher in treatments that used this soil, indicating its role in the antioxidant protection of plants. Under environmental stress conditions, such as water deficit and increased temperature, it was observed that M. brauna develops adaptive mechanisms, especially up to 50% of field capacity. In warmer environments with greater vapor pressure deficit, seedlings showed greater root growth and increased antioxidant enzyme activity, although with higher levels of oxidative stress. In milder environments, photosynthetic rates and water use efficiency were higher. It is concluded that the efficient production of M. brauna seedlings depends on the use of soil close to the mother trees, rich in beneficial microorganisms, and that the species presents a certain resilience to adverse conditions, adapting physiologically to different levels of water and thermal stress.
