Dear Colleague: Did you ever receive an answer to your question? I would be very interested! Many thanks! JPM Prof. Jean-Pierre Métraux Département de biologie Université de Fribourg Ch. du Musée 10 1700 Fribourg, Switzerland Tel.: 41 26 300 8811 Fax: 41 26 300 9740 http://www.unifr.ch/plantbio/