Ação dos subprodutos do nitroprussiato de sódio na germinação de sementes de alface sob estresse hídrico e térmico, em um cenário simulado de crise climática
Nenhuma Miniatura disponível
Data
2025-12-03
Autores
Bonfá, Yasmim Smarsaro
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
Abiotic stresses generate significant monetary losses due to the imposition of limiting conditions on agricultural production. Among these, climate change can cause not only water stress but also thermal stress, impacting seed germination in such a way as to compromise the full development of the crop, its ability to maintain yield, and consequently the food security of human populations. Sodium nitroprusside (SNP), an inorganic complex, releases cyanide (CN) and nitric oxide (NO) as byproducts of its spontaneous decomposition; the latter is commonly used in germination studies to mitigate the effects of abiotic stress. However, the substance responsible for the beneficial effects attributed to SNP remains unclear. This is particularly important when different products are released by the same compound. Considering the release of byproducts derived from SNP, this study sought to evaluate the role of these byproducts in promoting the benefits of exposing lettuce seeds under water and heat stress to the exogenous administration of SNP and the NO scavenger, PTIO (2-phenyl 4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide). This allowed for a focused elucidation of the contribution of each molecule to the germination results obtained in the presence and absence of NO. A total of 12 treatments were tested: Water, PEG, SNP, SNP+PEG, SNP+PTIO, SNP+PTIO+PEG at temperatures of 20°C and 30°C. The following attributes were evaluated: germination percentage (%G), germination speed index (GSI), fresh mass (FM) and dry mass (DM), root length (R), shoot length (SL), catalase (CAT) and peroxidase (POX) enzyme activity, total protein content, and malondialdehyde (MDA) level. It was found that under water deficit, nitric oxide was essential in overcoming the stress, while under heat stress, it loses its role as a promoter of benefits to cyanide. NO continues to contribute to the system, but apparently its role becomes solely in promoting germination; in contrast, it is cyanide that allows the plant to continue its development. In the simulated climate crisis scenario where water and thermal stress act simultaneously, the action pattern resembles the results found for thermal stress, showing that the water deficit can be overcome by nitric oxide from the SNP. However, whenever there is an increase in temperature, it is cyanide that sustains the overcoming of the difficulties presented by the stresses promoted in this work, regardless of whether it is being influenced by high temperatures or by the synergy of water and thermal stresses
Descrição
Palavras-chave
Estresse hídrico , Estresse térmico , Óxido nítrico , Cianeto , Alface , Mudança climática , Water stress , Heat stress , Nitric oxide , Cyanide , Lactuca sativa , Climate change