Ben-hod, G., Department of Botany, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
Losner, D., Department of Weed Research, ARO, Regional Experimental Station, 31999, Newe Ya'ar, Israel
Joel, D.M., Department of Weed Research, ARO, Regional Experimental Station, 31999, Newe Ya'ar, Israel
Mayer, A.M., Department of Botany, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel

Calli derived from seedlings of the parasitic plant Orobanche aegyptiaca were grown on enriched nutrient agar. Growth was enhanced by the addition of 0.1 mg 1-1 NAA and 5 % coconut milk. The calli developed two kinds of elongated protrusions: thin ones which resemble the young root radicle and thick ones which resemble the adventitious roots of Orobanche plants. Both formed pad-like structures when touching the substrate. In liquid culture, some of the calli were observed to surround isolated cultured tomato roots. © 1991 Annals of Botany Company.