GERMINATION OF PROTEA COMPACTA ACHENES: THE RELATIONSHIP BETWEEN INCUBATION TEMPERATURE AND ENDOGENOUS CYTOKININ LEVELS

Protea compacta achenes germinated best when incubated at 10°C. Under these conditions 50% of the propagules germinated.
Stratification (moist conditions at 5°C) for periods of 30 or 60 days prior to shifting the achenes to the optimum incubation temperature increased germination.
Sixty days of stratification resulted in 78% of the achenes finally germinating.
Most of this germination occurred during the stratification process itself.
A comparison between the endogenous cytokinin levels of achenes incubated at the optimum incubation temperature (10°C) and the stratification temperature (5°C) indicated that prior to the commencement of germination the level of these hormones increased.
This increase was due to compounds which cochromatographed with zeatin and ribosylzeatin.
In unimbibed achenes most of the cytokinin-like activity co-chromatographed with "conjugated" or storage forms of these hormones.
The overall pattern of cytokinin change during incubation at the two different temperature regimes and the inability of cytokinin to stimulate germination suggest that changes in endogenous cytokinins within the seeds were probably not related to the breaking of dormancy but rather to radicle elongation.

I International Protea Research Symposium

J.J. Mitchell, J. Van Staden, N.A.C. Brown

https://doi.org/10.17660/ActaHortic.1986.185.3