OVERCOMING SEED DORMANCY IN EX-SITU PLANT GERMPLASM CONSERVATION PROGRAMS - AN EXAMPLE IN THE ENDEMIC ARGYRANTHEMUM (ASTERACEAE, ANTHEMIDEAE) SPECIES FROM THE CANARY-ISLANDS

Germplasm of 21 diverse Argyranthemum taxa was collected from contrast ing ecological zones in the Canary Islands. Seed dormancy was consider able in the majority of taxa. Extensive investigations, based on a ger mination test procedure algorithm for Asteraceae, with achenes from ra y and disc florets of five contrasting taxa identified a procedure to promote full (greater-than-or-equal-to 85%) germination of the seeds f rom both ray and disc florets of all five taxa; viz, excision of the s eeds from the achenes, followed by testing at 15-degrees-C with 2.6 x 10(-3) M GA3 co-applied. Subsequent tests showed that this regime was effective in promoting full germination in seeds from both ray and dis c florets of the remaining 16 taxa. The results are discussed in the c ontext of ex situ plant germplasm conservation.