Effect of flooding on survival and initial growth of Ocotea pulchella (Nees) Mez. seedlings in semi-controlled light conditions
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Data
2011-06-01
Autores
Pires, Luciana Andrea
Cardoso, Victor José Mendes [UNESP]
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Editor
Sociedade Botânica do Brasil
Resumo
Considerando-se a ocorrência de Ocotea pulchella em áreas sujeitas a alagamentos periódicos, neste trabalho estudou-se a sobrevivência e desenvolvimento inicial de plântulas (dois meses de idade) e juvenis (nove meses de idade) de O. pulchella em resposta a alagamento sob diferentes regimes luminosos, variando-se tanto a qualidade como a quantidade de luz, com o objetivo de se verificar a influência desse fator sobre a resposta ao alagamento. Foram testados três níveis de água no solo (capacidade de campo, alagamento médio - este apenas em plântulas - e alagamento total) e quatro níveis de luz (pleno sol, sombreamento neutro, sombreamento enriquecido com vermelho extremo e sombreamento neutro mais vermelho extremo). A sobrevivência das plântulas e juvenis ao longo de um ano foi relativamente alta, ao passo que o crescimento foi afetado negativamente em pleno sol e alagamento, dependendo das condições de luz. O crescimento de plântulas foi inibido pelo alagamento de solo, independentemente das condições de luz, enquanto que os resultados foram similares nas plantas submetidas a alagamento médio e capacidade de campo. O alagamento também inibiu o crescimento de juvenis, sendo que as respostas das plantas praticamente não foram afetadas pelos regimes de luz. Os resultados sugerem que plântulas de O. pulchella podem sobreviver no sub-bosque, mesmo em áreas sujeitas a alagamento, formando um banco de plântulas de crescimento lento. A espécie parece tolerar o alagamento do solo por tempo relativamente prolongado, quando não está sob luz direta. Por outro lado, algumas respostas ao sombreamento, de plantas submetidas a inundação, parecem ser afetadas pela quantidade e qualidade da luz.
Taking into account the occurrence of Ocotea pulchella in areas subjected to periodic flooding, this work aimed to evaluate the survival and initial development of Ocotea pulchella seedlings (2 months old) and juveniles (9 months old) in response to waterlogging under different light regimes by varying both light quantity and light quality, in order to test for possible flood tolerance of the species as affected by light conditions. Three levels of soil moisture (field capacity, mean flooding - only for seedlings - and full flooding) and four light treatments (full sun, neutral shade, far red enriched shading and neutral plus far red) were tested. The survival of seedlings and juveniles during one year was relatively high, whereas growth was negatively affected by full sun and flooding. Seedling growth was inhibited by soil waterlogging whatever the light condition, whereas plant growth at field capacity and mean fl ooding was similar. Flooding also inhibited the growth of juveniles, and that response was practically not affected by the light regimes. The results suggest that Ocotea pulchella seedlings can survive in the understory, even in areas subject to fl ooding, forming a slow-growth seedling bank. The species seems to tolerate relatively long-term soil waterlogging when kept out of direct sunlight. Otherwise, responses of waterlogged plants to shading seem to be aff ected by irradiance and light quality.
Taking into account the occurrence of Ocotea pulchella in areas subjected to periodic flooding, this work aimed to evaluate the survival and initial development of Ocotea pulchella seedlings (2 months old) and juveniles (9 months old) in response to waterlogging under different light regimes by varying both light quantity and light quality, in order to test for possible flood tolerance of the species as affected by light conditions. Three levels of soil moisture (field capacity, mean flooding - only for seedlings - and full flooding) and four light treatments (full sun, neutral shade, far red enriched shading and neutral plus far red) were tested. The survival of seedlings and juveniles during one year was relatively high, whereas growth was negatively affected by full sun and flooding. Seedling growth was inhibited by soil waterlogging whatever the light condition, whereas plant growth at field capacity and mean fl ooding was similar. Flooding also inhibited the growth of juveniles, and that response was practically not affected by the light regimes. The results suggest that Ocotea pulchella seedlings can survive in the understory, even in areas subject to fl ooding, forming a slow-growth seedling bank. The species seems to tolerate relatively long-term soil waterlogging when kept out of direct sunlight. Otherwise, responses of waterlogged plants to shading seem to be aff ected by irradiance and light quality.
Descrição
Palavras-chave
Floresta de Restinga, juvenis, alagamento, desenvolvimento, Restinga forest, juveniles, waterlogging, development
Como citar
Acta Botanica Brasilica. Sociedade Botânica do Brasil, v. 25, n. 2, p. 435-444, 2011.