Anaesthetic stimulation of Amaranthus albus seed germination: Interaction with phytochrome

Abstract

Exposure to solutions of acetaldehyde, ethanol and n‐propanol ranging from 0.06 to 0.6 M for about 5 h induced photosensitivity in imbibed Amaranthus albus L. seeds which normally would be insensitive. When the seeds were made dormant by pre‐treattnent with continuous incandescent light for 24 h, n‐propanol promoted germination np to 80% provided the active form of phytochrome was present. Pre‐treatment of seeds with continuous incandescent light terminated by far‐red reduced the n‐propanol‐stimulated germination to about 33% which could again be increased by a red irradiation. Red light and n‐propanol also interacted in seeds made insensitive to red treatment by 20°C in darkness. Loss of the n‐propanol stimulation resulted from treatment in continuous far‐red for 2 or more days, even when a red irradiance and n‐propanol treatment were combined. It is suggested that n‐propanol may act at a membrane level.

Inhibition of germination inAmaranthus albusseeds by prolonged irradiation: a physiological basis

“…Seeds were returned to darkness and germination was scored after a total of 3 days at 30°C. Taylorson (1985a) showed previously that solutions of n-propanol would overcome the inhibitory effects of 24 h CIL on A. albus seed germination and that the stimulatory effect of the n-propanol could be largely negated if an FR irradiation concluded the 24 h CIL. Similar results were obtained with ethanol (Table 4), which indicate that enough P fr was present at the end of the 24 h CIL exposure to cause germination when ethanol was also provided.…”

Responses of Redroot Pigweed (Amaranthus retroflexus) and Witchgrass (Panicum capillare) Seeds to Anesthetics

“…Seeds were stored at -20 C in sealed containers. Lots of 100 seeds were imbibed in 9-cm Petri dishes with two Whatman # 3 filter papers moistened with 8 ml distilled H 2 0. Seeds were kept in dark ness in black cloth bags in germination cabinets at the in dicated temperatures ±1 C and near 100% relative humidity.…”

“…Ctr.-West, Beltsville, MD 20705. 3 Letters following this symbol are a WSSA-approved computer code from Composite List of Weeds, Weed Sci. 32, Suppl.…”

“…A number of substances having anesthetic activity in animals relieve dormancy in some seeds (1,3,11). The most active substances have been alcohols with chain lengths of five carbons or less, especially ethanol and propanol.…”