A recently commercialized natural bio-stimulant, ComCat®, that contains three active
brassinosteroids (BRs) of which two were identified previously, was scrutinized in this
study for its potential to be applied in the agricultural industry. Concerning objective
(1), seven biotests were employed to quantify the bio-stimulatory activity of ComCat®
under laboratory and glasshouse conditions. The product was tested at different
concentration levels and the 0.5 mg â-1 application repeatedly emerged as the
optimum concentration in terms of contributing towards increases in all of the
parameters measured. Treatment with ComCat® had little or no effect on seed
germination, but especially root growth of seedlings from different crops was
significantly and consistently induced.
Concerning objective (2), two cultivars for each of five test crops were treated
with ComCat® over two growing seasons under field conditions in order to ascertain
their yield response. Some of the test crops, but not all, showed cultivar sensitivity to
treatment with ComCat®. However, overall the significant yield increases measured in
one or both cultivars of the five different test crops and in one or both seasons
confirmed the potential of ComCat® to be applied in agriculture and to contribute to
economic prosperity for a farmer.
Concerning objective (3), gas chromatographic analyses of a crude extract of
the product as well as semi-purified fractions thereof by, using internal BR standards,
were employed to identify an unknown BR contained in ComCat®. This was
confirmed to be 24-epi-brassinolide. The latter as well as the previously identified 24-
epi-castasterone and 24-epi-secasterone are known to be active BRs of the
brassinosteroid group.
In conclusion, the bio-stimulatory characteristic of ComCat® was confirmed
both in vitro and in vivo under laboratory, glasshouse and field conditions in this
study. Significant yield increases in all of the test crops over two seasons in some
instances, confirmed the potential of ComCat® to be applied sustainably in the
agricultural practice. Based on the results obtained in this study, three possible
application methods of ComCat® are suggested. These include 1) seed treatment, 2)
foliar application or 3) soil application.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-08152012-115830 |
| Date | 15 August 2012 |
| Creators | Hüster, Thomas |
| Contributors | Prof WJ Swart, Prof JC Pretorius |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-08152012-115830/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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