Effect of light and two isomers of nitrophenyl indole-2-carboxylic acid ongermination of Cenchrus ciliaris seeds

Effect of light and different concentrations of m- and p-isomers of 1-nitro phenyl indole-2-carboxylic acid (NPICA) has been investigated on the germin ation of Cenchrus ciliaris seeds. Light not only delayed germination of the seeds but also reduced the germination by greater than or equal to 62%. Pr esence of 15 to 45 ppm of either 1-m- or 1-p-NPICA in the germination mediu m showed a negative effect on seed germination whereas, presence of 30 ppm of either of the two isomers improved germination, albeit slightly and only in the presence of light.