Effect of eucalyptus oil on germination and growth of Phaseolus aureus Roxb

Crude oil from Eucalyptus globulus and E. citriodora was extracted and the rich components, cineole and limonene were fractionated. The vapours of these oils and fractions were adsorbed onto the soil in one set of germination trials while in the other set a vapour column of volatile oils was maintained above the oil-treated soil. In both sets seed germination, seedling growth, relative growth rate, water content, height and number of leaves of Phaseolus aureus var. ML-267 were compared to those of controls. All parameters were found to be significantly affected. The effect was more pronounced with a combination of eucalyptus oil onto soil and a vapour-rich air column. There was a strong correlation between the vapour concentration and its inhibitory effect.