Influence of temperature, light and plant growth regulators on germination of black pepper (Piper nigrum L.) seeds

Effects of temperature, light and different concentrations of plant growth regulators on germination of Piper nigrum L. seeds was studied under controlled environmental conditions. Black pepper seeds were placed in Petri dishes with filtration papers and the germination and radical development followed during eighteen days periods. The seeds generally germinated within six or seven days. There was no difference in percent germination between dark and light treatments, but the development of radical length was significantly influenced by both light and temperature. Germination was highest at 30°C, but seeds also germinated at 25 and 35°C. No germination was observed at low (20°C) and high (40 and 45°C) temperatures. The plant growth regulators enhanced the seeds germination and radical length different degree. The results are consistent with the Piper nigrum L.being recalcitrant species need a certain environment condition to germinate.   Key words: Temperature, light, plant growth regulator, black pepper, Piper nigrumL.