The endogenous cytokinin levels in the brown alga Ecklonia maxima
(OSBECK) PAPENF., and the effect of applications of the seaweed concentrate
(Kelpak 66) prepared from this alga, on the growth and yield of various plants
was investigated.
Tentative identification of the cytokinins present in Ecklonia maxima
using High Performance Liquid Chromatography revealed the presence of cis
and trans-ribosylzeatin, trans-zeatin, dihydrozeatin and isopentenyladenosine.
Seasonal and lunar variations in the endogenous cytokinin levels in fresh
and processed Ecklonia maxima material were investigated. Lamina, stipe and
holdfast regions of one, two and three metre plants harvested from February
1981 until January 1982 together with samples of processed material from the
normal production run, collected over the same period were used in this
investigation. Analysis revealed both qualitative and quantitative changes in
the cytokinin levels which were closely correlated to the seasonal patterns of
growth of Ecklonia maxima. During summer zeatin, ribosylzeatin and their
dihydroderivatives were responsible for most of the detected activity. The
cytokinin glucosides increased above the levels of free cytokinins during winter.
The lunar cycle study of material harvested on a daily basis during April - May
1983 revealed marked fluctuations in the cytokinin levels in the various tissues
of two metre plants which were closely correlated with the phases of the moon.
Greenhouse trials were conducted to determine the effects of the
commercially available seaweed concentrate (Kelpak 66) on the growth of
Lycopersicon esculentum MILL. plants in nematode infested soil. Kelpak 66
at a dilution of 1 : 500 improved the growth of treated plants significantly, irrespective of whether it was applied as a foliar spray at regular intervals, or
whether the soil in which the plants were grown was flushed once with the diluted
seaweed concentrate. Root growth was significantly improved whenever the
seaweed concentrate was applied. Associated with this improved root growth
was a reduction in the infestation of Meloidogyne incognita (KOIFORD and WHITE)
CHITWOOD.
Finally, the effect of seaweed concentrate and fertilizer applications
on the growth and endogenous cytokinin content of Beta vulgaris L. and Phaseolus
vulgaris L. plants was investigated. Seaweed concentrate at a dilution of 1 :
500 applied as a foliar spray improved the growth of treated plants significantly,
irrespective of whether it was applied on its own or together with a chemical
fertilizer. Root growth and the endogenous cytokinin content of these roots
increased with seaweed concentrate application. Increases were also detected
in the cytokinin content of fruits of Phaseolus vulgaris plants treated with seaweed
concentrate. Associated with this increase in the cytokinin content was an
increase in the dry mass of the fruit from treated plants.
The significance of these findings and the possible relationship between
the endogenous cytokinins present in Ecklonia maxima and the effect of the
seaweed concentrate on plant growth is discussed. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1984.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10994 |
| Date | January 1984 |
| Creators | Featonby-Smith, Bryan Charles. |
| Contributors | Van Staden, Johannes. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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