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Germination and mitotic circadian rhythms in Luffa cylindrica (Cucurbitaceae)

Raquel de Castilhos; Elena Diehl-Fleig

Laboratório de Genética, Departamento de Biologia, UNISFNOS, Caixa Postal 275, 93001-970 São Leopoldo, RS, Brasil. Send correspondence to E.D.-F.

ABSTRACT

The rates of germination of seeds of Luffa cylindrica, coming from two populations, Horizontina and Sao Sebastião do Cai, RS, in different combinations of light and temperature, were compared. The highest rates of germination of both populations occurred at 27°C, independent of the photoperiod conditions. Horizontina's population presented a higher rate of germination in the tested conditions and lids comld indicate genetic differences and/or different dormancy degrees between the populations.
The mitotic and metaphasic levels in root tip meristems were analysed at intervals of one hour during 24 hours, and peak times were found to be at 1:00 A.M. and 2:00 A.M. The interphasic nuclei were of the semi-reticulated type. All the somatic cells analysed had 2n = 26.

Keywords: Germination; Circadian rhythms; Luffa cylindrical; Cucurbitaceae.

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