Resposta de plântulas de aveia ao estresse por ácidos acético e butírico

Abstract

White oat is an excellent alternative winter crop for crop rotation systems. The decomposition of organic matter retained on the soil in no-till conditions associated with poor drainage or excessive moisture increase the formation of organic acids, including acetic and butyric acids, with high phytotoxic potential. This study aimed to evaluate the effect of acetic and butyric acids on germination and early seedling development of different oat cultivars. The experiment was a completely randomized block design, where seeds of the cultivars Afrodite, Albasul, Brisasul, FAEM 06, IAC 7, URS 21 and URS Taura, were subjected to four levels of acetic (0, 4, 8 and 12 mM) and butyric (0, 3, 6 and 9 mM) acids. Seeds were kept in a germination chamber for ten days. The traits evaluated were: shoot length (SL), root length (RL), and germination percentage (% GER). Butyric acid was more toxic than acetic acid, impairing more root development than shoot length. The cultivars IAC 7 and Brisasul were more sensitive and the cultivars URS Taura and Afrodite were tolerant to the organic acids studied. In the control and in the treatment with 12 mM acetic acid, we found correlation between RL and %GER. There is a large variation among cultivars in response to acetic and butyric acids.Key words: phytotoxicity, Avena sativa, germination, root, shoot. Resposta de plântulas de aveia ao estresse por ácidos acético e butíricoResumo A aveia branca é uma excelente opção como cultura de inverno em sistemas de sucessão de culturas. A decomposição do material orgânico, mantido na superfície do solo no plantio direto, associado a condições de má drenagem ou umidade excessiva, acentua a formação de ácidos orgânicos. Dentre estes, os ácidos acéticos e butírico apresentam grande potencial fitotóxico. O objetivo do trabalho foi avaliar o efeito dos ácidos acético e butírico na germinação e no desenvolvimento inicial de plântulas de diferentes cultivares de aveia branca. O experimento foi conduzido em blocos completamente casualizados, onde sementes das cultivares Afrodite, Albasul, Brisasul, FAEM 06, IAC 7, URS 21 e URS Taura foram embebidas em quatro doses de ácido acético (0, 4, 8 e 12 mM) e butírico (0, 3, 6 e 9 mM). As sementes foram mantidas em câmera de germinação por dez dias. Foram avaliados os caracteres comprimento da parte aérea (CPA), comprimento de raiz (CR) e a porcentagem de germinação (% GER). O ácido butírico demonstrou-se mais fitotóxico que o ácido acético, sendo o desenvolvimento das raízes mais afetado que a parte aérea. As cultivares IAC 7 e Brisasul demonstraram-se mais sensíveis e as cultivares URS Taura e Afrodite demonstraram-se menos afetadas pelos ácidos orgânicos em estudo. Sem a adição de ácidos e na dose de 12 mM de ácido acético, verificou-se a correlação entre % GER e CR. Existe grande variabilidade entre as cultivares estudadas, em resposta aos ácidos acético e butírico.

Efeitos de ácidos orgânicos na germinação e crescimento inicial de Brassica napus L. var. oleifera

“…Regarding RPsl, a development reduction was observed for Hyola 433 while the other genotypes were not affected by butyric acid concentration increase (Table 4). A similar result was found in oats, in which one of the cultivars studied was negatively affected with increasing doses of butyric acid (SILVEIRA et al 2014). These results indicate that the Hyola 433 genotype shows sensitivity to the butyric acid stress.…”

“…On the other hand, Hyola 50, Hyola 61, and Hyola 575CL did not differ at higher butyric acid concentrations. Germination reduction at different doses of butyric acid were not detected for oats (SILVEIRA et al 2014). Thus, the plant responses under butyric acid stress appear to be variable within and between plant species.…”

“…In Southern Brazil, the most used agricultural practice is no tillage, whose main feature is to keep the soil always covered with plant residues. As the decomposition of these residues occurs, the formation of organic acids increases (SILVEIRA et al 2014). The main acids produced at this condition are the short chain aliphatic acids with low molecular weight, among them acetic, butyric and propionic acids, which occur in a proportion of 6:3:1, respectively (ANGELES et al 2005, BOHNEN et al 2005.…”

“…The presence of organic acids in the soil can negatively affect plant biological processes such as germination, shoot and root growth (KOPP et al 2012a, SILVEIRA et al 2014, as well as interfere in the processes of energy formation through mitochondria functioning impairment (BORTOLON et al 2009).…”

Response of white oat genotypes to water stress

“…In Brazil, their cultivation occurs mainly in the southern states, where the state of Rio Grande do Sul stands out, being responsible for approximately 70% of the national production. However, the production of this cereal has been expanding for new areas, reaching the Midwest region (Silveira et al 2014, CONAB 2019. This cereal is considered as a winter crop, with great importance in the grain production system, besides being used in the integration of livestock farming in Brazilian regions (Silveira et al 2013).…”