Annals of Botany 67: 511-515, 1991
© 1991 Annals of Botany Company
RESEARCH-ARTICLE |
Influence of Exogenous Hormones on Somatic Embryogenesis in Hevea brasiliensis


*Laboratory of Applied Plant Physiology, University of Montpellier 2 F-34095 Montpellier, Cedex 5
In vitro Culture Laboratory, Institut de Recherches sur le Caoutchouc IRCA-CIRAD, BP 5035, F-34032 Montpellier, Cedex, France
For correspondence
Accepted: 21 January 1991
Generating somatic embryos from the inner teguments of Hevea seeds is difficult. Like other ligneous plants, the rubber-tree is generally considered to be recalcitrant with regard to somatic embryogenesis. In this paper we show that when conventionally used amounts of both 3, 4-dichlorophenoxyacetic acid (3, 4-D) and benzylaminopurine (BAP) are reduced by 24 times and when the length of exposure to these hormones is also reduced, the embryogenic capacity of calli increases without affecting callogenesis. The germination of several embryos and plantlets was obtained. We conclude that an excess of auxin and cytokinin in the medium, even of a weak auxin such as 3, 4-D, and the prolonged exposure to these hormones suppress the embryogenic capacity of the callus.
Hevea brasiliensis, rubber-tree, somatic embryogenesis, hormones