Influence of Light on Seed Germination in Eupatorium odoratum L.

Eupatorium Odoratum L., a weed posing threat to several plantation crops, prefers open situations and is conspicuously absent from heavily shaded areas and well established plantations with dense canopy. The cypsella germinate in soil only if these are placed just below the surface and not deep, light is highly promotory to germination in seeds stored for short period, Prolonged storage substitutes this effect of light. Maximnm germination occurred at 150 lux and at higher intensities germination is reduced. Red light strongly promotes germination whereas blue and far red are inhibitory. As storage is found to crase photoblastism in E. adoratum, the light requirement of the fresh cypsella for germination,does not impose any limitation on the emergence of the weed in nature. Strong light requirement of the species at subsequent stages of growth, may be responsible for its absence from shaded regions.