Rooting of buchu cuttings (Genus : Agathosma)

Karsen, P. A. (2003-12)

Copies no. 3007841664 and 3007841665 are photocopies of the original.

Thesis (MScAgric)-- University of Stellenbosch, 2003.

Thesis

ENGLISH ABSTRACT: Buchu (Agathosma betulina and A. crenulata) are grown commercially as an aromatic crop and are endemic to the Western Cape of South Africa. Poor rooting of cuttings have limited the development of superior clones. Under standard mist bed conditions terminal, sub-terminal or basal stem cuttings were taken from March to August. When not treated with an auxin, rooting percentages of between 20 and 25 were obtained. Rooting percentages increased to between 40 and 45 after treatment with 500-1000 ppm indolebutyric acid (lBA). Substituting lBA with naphthaleneacetic acid (NAA) did not improve rooting. There was a tendency for cuttings with fewer than four leaf pairs to give lower rooting percentages. Plants of Agathosma betulina x A. crenulata, grown in Paarl, and A. betulina, grown in Piketberg, were used as source plants for making cuttings. Paarl plants were shaded with 80 percent shade and Piketberg plants with 60 or 80 percent shade respectively from February to October 2002. Plants in full sun served as a control. Plants were pruned back initially in February and then two months before samples were taken in March, June, August and October at both locations. New shoots were used as cuttings. Terminal cuttings for rooting and for carbohydrate analyses were collected on four different dates (March, June, August and October). Cuttings were treated with 500 ppm indolebuteric acid (lBA) and placed in misting beds with bottom heating (18-25°C) for a period of three months. Shading reduced rooting of cuttings from the Paarl plants. However, it did not significantly increase rooting of cuttings taken from Piketberg plants. Rooting percentage was the highest in August (43%) for cuttings from sun grown plants in Paarl. No consistent relationship between, respectively, dry mass or carbohydrate content of cuttings and rooting could be established. Terminal current years' growth, taken from Agathosma crenulata x A. betulina (hybrid) softwood cuttings, collected in January 2002, were extracted with methanol and fractioned by thin layer chromatography (Silica gel) in isopropanol: acetic acid: water (4: 1:1 v/v). The chromatographs were divided in ten fractions and were bio-assayed for a rooting co-factor with the mung bean rooting test. Extracts from buchu cuttings showed significant activity at the Rf values of co-factor 3. Co-factors 1,2 and 4 do not seem to be present in significant quantities. However, co-factors with Rf values different from previous reported values were present in significant quantities. No inhibition was found in buchu. In fact, all Rf values stimulated rooting.

AFRIKAANSE OPSOMMING: Boegoe (Agathosma betulina x A. crenulata) word kommersieël verbon as 'n aromatiese gewas en is endemies tot die Wes-Kaap. Die ontwikelling van superieure klonale materiaal word beperk deur swakbeworteling. Terminale, sub-terminale en basale steggies is gesnyonder standaard misbed toestande van Maart tot Augustus. Beworteling was tussen 20 en 25 persent as geen ouksien gebruik word nie. As indolebottersuur (IBS) gebruik word tussen 500-1000 dpm, verhoog die bewortelingspersentasie tot tussen 40 en 45 persent. Die gebruik van naftaleen asynsuur (NAS) in plaas van IBS het nie beworteling verbeter nie. Daar was a tendens dat steggies wat minder as vier blaarpare gehad het 'n verlaging in bewortelingspersentasies gehad het. Plante van Paarl, A. betulina x A. crenulata, en Piketberg, A. betulina, is gebruik as plantmateriaal vir steggies. Plante in die Paarl was onder 80 persent skadu geplaas en plante in Piketberg onder 60 en 80 persent skadu van Februarie tot Oktober 2002. Plante in vol son was as 'n kontrole gebruik. Plante was eers in Februarie teruggesny en dan weer twee mande voor monsters geneem is. Die monsters is in Maart, Junie, Augustus en Oktober geneem in beide liggings. Terminale steggies is vier keer ingesamel (Maart, Junie, Augustus en Oktober) vir beworteling en koolhidraat analises. Die steggies is met 500 dpm IBS behandel. Daarna is die steggies vir drie maande in die misbed geplaas met bodem-verhitting (18- 25°C). Dit is gevind dat die gebruik van skadu die beworteling in Paarl verminder het alhoewel die beworteling in Piketberg nie beduidend beinvloed is nie. Die hoogste bewortelingspresentasies is waargeneem in Augustus (43%) in Paarl van plante wat in vol son was. Geen verband tussen onderskeidelik die droe massa of koolhidraat inhoud en beworteling kon gevind word nie. Terminale steggies van dieselfte jaar se groei van Agathosma betulina x A. crenulata (hibried) is in Januarie 2002 ingesamel. Die materiaal is geëkstraheer en gefraksioneer deur dunlaag kromatografie in isopropanol: asynsuur: water (4: 1:1 v/v). Die kromograaf is in 10 fraksies verdeel. Die fraksies was bioassaieer VIr beworteling ko-faktore met die mungboontjie bewortelingstoets. Die ekstrakte van boegoe het beduidende aktiwiteit by die Rf waardes van ko-faktor 3 getoon. Ko-faktore 1, 2 en 4 is nie in groot genoeg hoeveelhede waargeneem nie. Ko-faktore, wat nie voorheen gevind is nie, is waargeneem in beduidende hoeveelhede. Geen inhibitors is in boegoe gevind nie en al die getoetste ko-faktore het beworteling gestimuleer.

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