Abstract:
The experiments were undertaken at the laboratory of the Plant Protection
Department, College of Agricultural Studies, Sudan University of Science and
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Technology at Shambat. The experiments were conducted in the period April to
June 2007. The objectives of the experiment were to study the effects of light,
darkness and wetting and drying period on germination of the aquatic weed
Typha angustata Bory and chub. The seeds were incubated at ambient
temperature. Light manipulation was effected by an electric bulb (Candle 60W)
and by wrapping the plates, containing the seeds, in aluminum foil. Treatments
were arranged in Complete Randomized Design (CRD) with 6 replicates. The
results showed that T. angustata displayed negligible germination in the dark.
Light promoted germination considerably. Incubation of the seeds in the dark for
24 and 72 h resulted in 3 and 19 % germination. Corresponding germination
figures in light were 87 and 91 %. Pre-soaking of the seeds, in light for 2h
promoted germination in the dark. Seeds pre-soaked in water and exposed to
light for 2 h prior to incubation in the dark for 48 h displayed 95% germination.
Seeds pre-soaked in water and incubated in the dark showed reduced
germination on subsequent exposure to light. Seeds pre-soaked in the dark for
12 h or more prior to exposure to light for 2 h, displayed 3-6% germination,
while those pre-soaked in continuous light exhibited 84% germination. Drying
of dark imbibed seeds prior to exposure to light restored germination, albeit not
completely. Plausible mechanisms of light promotion of T. angustata
germination and the significance of dark inhibition of germination on its
management were discussed.
