H. Atta-AIIa1 , B.G. McAiister2 and J. van Staden2*
1Suez Canal University, Faculty of Agriculture, Department of Horticulture. lsmalia. Egypt
2Natal University Research Unit for Plant Growth and Development. Department of Botany, University of Natal Pietermaritzburg.
Private Bag X01 , Scottsville, 3209 Republic of South Africa
Received 9 ,'vfarch 1998; revised 15 Juzv /998