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The objective of the present study was to evaluate the interference of water excess in soil on the growth of young coffee plants of the Mundo Novo and Catuaí cultivars.Plants were subjected to the following three different substrate water availability conditions: control (wellwatered), continuous substrate waterlogged, and intermittent substrate waterlogged. Several growthrelated traits were evaluated over the course of 19 weeks. Based on the number and quality of the affected variables from all forms of analyses, the Catuaí cultivar showed greater sensitivity to waterlogging. Both cultivars exhibited growth inhibition in response to substrate waterlogging stress, which was exacerbated by premature leaf dropping.Efeitos do excesso de água no crescimento de mudas de cafeeiro (Coffea arabica L.) RESUMO. O presente trabalho visou avaliar a interferência do excesso hídrico do solo sobre o crescimento de plantas jovens de café, cultivares Mundo Novo e Catuaí. As mudas foram submetidas a três condições de disponibilidade de água no substrato: controle (mudas irrigadas), encharcamento contínuo do substrato e encharcamento intermitente do substrato. Diversas características de crescimento foram analisadas ao longo de 19 semanas. Baseado no número e qualidade das variáveis afetadas em todas as análises, a cultivar Catuaí mostrou maior sensibilidade ao encharcamento.. Ambas as cultivares de café apresentaram inibição do crescimento em resposta ao estresse por encharcamento do substrato, que foi agravado pela queda prematura das folhas.Palavras-chave: encharcamento do solo, hipoxia, cultivar mundo novo, cultivar catuaí.

The aim of the present study was to find out the effect of calcium on flooded maize seedlings by anatomical and ultra‐structural analyses and by measuring the enzyme activity and gene expression of polygalacturonase (PG) and superoxide dismutase (SOD). For this, maize seeds were placed to germinate in germination paper saturated with CaCl2 0.75 %. Then, 4‐day‐old seedlings were subjected to flooding in the presence or absence of CaCl2. Mesocotyl sections were sampled daily for the anatomical and ultra‐structural analyses, RT‐qPCR and activity of SOD and PG. The results showed that the presence of calcium in the flooding buffer increases the tolerance of maize seedlings by 1 day when compared to seedlings flooded in the absence of this element. The reason for this longer survival is that calcium maintains the integrity of the cell wall and attenuates the effects of oxidative stress. Owing to this fact, the seedlings remained alive and firm for up to 7 days.

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