Optimizing the micropropagation protocol for the endangered Aloe polyphylla: can meta-topolin and its derivatives serve as replacement for benzyladenine and zeatin?
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Benzyladenine (BA) is the most widely used cytokinin in the micropropagation industry due to its effectiveness and affordability. It, however, has disadvantages such as genetic alteration and abnormal growth in some plants. Naturally occurring zeatin on the other hand is not as widely used as BA and is far more expensive. The use of meta-topolin and its derivatives as alternatives to BA and zeatin, both of which frequently have negative effects in tissue culture was investigated. In vitro grown Aloe polyphylla (an endangered medicinal and ornamental aloe) were cultured on full strength Murashige and Skoog basal medium with different concentrations of cytokinins and solidified with 1% Bacteriological Agar (Oxoid No. 1). mT was the preferred cytokinin both in terms of multiplication rate and rooting. The optimum concentration that induced regeneration and rooting is 5.0 μM. The problem of hyperhydricity was totally controlled. Plants rooted spontaneously in multiplication medium, thus avoiding the extra rooting step of the protocol. More than 91% of the plants transferred to ex vitro conditions were successfully acclimatized.
KeywordsAromatic cytokinins Conservation Hyperhydricity Metabolites Multiplication rate Plant growth regulators Root and shoot growth
indole butyric acid
Murashige and Skoog (1962) medium
plant growth regulators
We acknowledge the financial support of the National Research Foundation (NRF), Pretoria. This work was also supported by the Grant Agency of the Czech Republic (GA 522/06/0108).
- Aubrey A (2002) Aloe polyphylla. Available online at http://www.plantzafrica.com/plantab/aloepoly.htm Cited 11 Sept 2005
- Chukwujechwu JC, Fennell CW, van Staden J (2002) Optimisation of the tissue culture protocol for the endangered Aloe polyphylla. S Afr J Bot 68:424–429Google Scholar
- Iwamura H, Fujiita T, Koyama S, Koshimizu K, Kumazawa Z (1980) Quantitative structure-activity relationship of cytokinin-active adenine and urea derivatives. Phytochemistry 19:1309–1319Google Scholar
- Krikorian AD (1995) Hormones in tissue culture and micropropagation. In: Davies PJ (eds) Plant hormones: physiology, biochemistry and molecular biology. Academic Publishers, The Netherlands, pp 774–796Google Scholar
- Kubalakova M, Strnad M (1992) The effect of aromatic cytokinins (populins) on micropropagation and regeneration in vitro. Biol Plant 34:578–579Google Scholar
- Leshem B, Sachs T (1985) ‘Vitrified’ Dianthus- teratomata in vitro due to growth factor imbalance. Ann Bot 56:613–617Google Scholar
- Leshem B, Shaley DP, Izhar S (1988) Cytokinin as an inducer of hyperhydricity in melon. Ann Bot 61:255–260 Google Scholar
- Mok MC, Martin RC, Dobrev PI, Vancovà R, Ho PS, Yonekura-Sakakibara K, Sakakibara H, Mok DWS (2005) Topolins and hydroxylated thidiazuron derivatives are substrates of cytokinin o-glucosyltransferase with position specificity related to receptor recognition. Plant Physiol 137:1057–1066PubMedCrossRefGoogle Scholar
- Tarkowská D, Doležal K, Tarkowski P, Åstot C, Holub J, Fuksová K, Schmülling T, Sandberg G, Strnad M (2003) Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus × canadensis leaves by LC-(+)ESI-MS and capillary liquid chromatography frit-fast atom bombardment mass spectrometry. Physiol Plant 117(4):579–590PubMedCrossRefGoogle Scholar