Fisiología do Phytophthora palmivora (Butl.) Butl., 2: Tensao de agua como fator na producao de zoósporos
Regarding the little knowledge on physiology of zoosporangia indirect germination in genus Phytophthora, was studied the conjugated action of relative air humidity and fluctuation of water temperature in zoospores production, in Phytophthora palmivora (Butl.) Butl. Thus was estimated the quantily of zoosporangia indirectly germinated in water after 2 hours, with the following treatment: -absence and presence of thermic shock at 10 grades centigrades for 5', returning to the laboratory conditions at 25 grades centigrades. Zoosporangia under these treatments were reported to stay for 12, 24, 36, 48, 60, 72, 84 and 96 hours in a confined room, carbon dioxide free and with 100, 90, 80 and 70 per cent of relative humidity. It was found that relative air humidity regulates physiological maturation and time of indirect zoosporangia germination, not exceeding more than 72 hours. Thermic shock in water is dispensables for zoosporangia germination when preceeded by dehydration. The water stress variation is apparently essential to break zoosporangia dormancy.
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| Format: | biblioteca |
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| Subjects: | THEOBROMA CACAO, PHYTOPHTHORA PALMIVORA, ENFERMEDADES FUNGOSAS, TENSION DE ABSORCION, HUMEDAD RELATIVA, AIRE, HUMEDAD, TEMPERATURA DEL AGUA, ESPORULACION, ZOOSPORAS, |
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| Summary: | Regarding the little knowledge on physiology of zoosporangia indirect germination in genus Phytophthora, was studied the conjugated action of relative air humidity and fluctuation of water temperature in zoospores production, in Phytophthora palmivora (Butl.) Butl. Thus was estimated the quantily of zoosporangia indirectly germinated in water after 2 hours, with the following treatment: -absence and presence of thermic shock at 10 grades centigrades for 5', returning to the laboratory conditions at 25 grades centigrades. Zoosporangia under these treatments were reported to stay for 12, 24, 36, 48, 60, 72, 84 and 96 hours in a confined room, carbon dioxide free and with 100, 90, 80 and 70 per cent of relative humidity. It was found that relative air humidity regulates physiological maturation and time of indirect zoosporangia germination, not exceeding more than 72 hours. Thermic shock in water is dispensables for zoosporangia germination when preceeded by dehydration. The water stress variation is apparently essential to break zoosporangia dormancy. |
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