CONTROL OF ETHYLENE AND USE OF POLYAMINES CAN OPTIMISE THE CONDITIONS FOR SOMATIC EMBRYOGENESIS IN COCONUT (COCOS NUCIFERA L.) AND PAPAYA (CARICA PAPAYA L.)

The protective conditions under which callus cultures are grown to prevent contamination and tissue desiccation cause the accumulation of ethylene, which, in turn may reduce growth and prevent somatic embryogenesis.
To demonstrate the importance of ethylene a study was undertaken on somatic embryogenic coconut (Cocus nucifera L.) and papaya (Carica papaya L.) callus cultures incubated with a number of medium additives which could either reduce production (aminoethoxyvinylglycine; AVG), protect from (silver thiosulphate; STS) or help combat ethylene-induced stress (polyamines). Increases in the ethylene concentration above coconut cultures reduced callus growth and somatic embryogenesis.
AVG (2 μM) and STS (3 μM) improved somatic embryogenesis by 100% and 67%, respectively.
Furthermore, coconut somatic embryogenesis was promoted (100%) by the addition of the polyamines, putrescine (7.5 mM) and spermine (1 μM) to the media.
Similarly, papaya callus cultures grew better in the presence of STS (ca. 50 μM) as well as being promoted into somatic embryogenesis by STS. Furthermore, STS (ca. 1 μM) aided somatic embryo proliferation, maturation and germination.
Better control of ethylene and the reduction of culture stress can increase both the quantity and quality of tissue available for genetic engineering of otherwise recalcitrant tropical fruit crops such as coconut and papaya.

International Symposium on Biotechnology of Tropical and Subtropical Species Part 2

S.W. Adkins, Y.M. Samosir, A. Ernawati, I.D. Godwin, R.A. Drew

Carica papaya L. Cocos nucifera L., polyamines, silver thiosulphate

https://doi.org/10.17660/ActaHortic.1998.461.54