Abstract
The perennial weeds,Eupatorium adenophorum Spreng. andEupatorium riparium Regel grow abundantly on roadsides, wastelands, ‘jhum fallows’ and other secondary successional communities in the hilly regions of north-east India. Propagation is predominantly by means of wind-borne achenes. Germination of these achenes was studied in relation to temperature, imbibition period and light conditions. At constant temperatures, germination was best at 25°C inEupatorium adenophorum and at 30°C inEupatorium riparium, while alternating temperatures of 15/25°C caused higher germination than the most favourable constant temperatures. The achenes were positively photoblastic and required an imbibition period prior to illumination. Twentyfour hours imbibition was sufficient to sensitize the achenes to light. Red light enhanced germination in both weeds although the effect was more marked inEupatorium adenophorum. The promotory effect of red light was reversed by subsequent exposure to far-red light, while the inhibitory effect of far-red light was removed by a subsequent red light treatment. The result shows a typical phytochrome-mediated germination.
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Narain Rai, J.P. Effect of temperature, imhibition and light on achene germination of two weedy species ofEupatorium . Proc. Indian Acad. Sci. 97, 325–332 (1987). https://doi.org/10.1007/BF03053387
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DOI: https://doi.org/10.1007/BF03053387