Deciphering the growth pattern and phytohormonal content in Saskatoon berry (Amelanchier alnifolia) in response to in vitro cytokinin application.

N Biotechnol. 2018 May 25;42:85-94. doi: 10.1016/j.nbt.2018.02.001. Epub 2018 Feb 15. Moyo M1, Aremu AO2, Plačková L3, Plíhalová L3, Pěnčík A3, Novák O3, Holub J4, Doležal K3, Staden JV5. Author information 1 Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209, South Africa; Department of Horticultural Sciences, Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 1906, Symphony Way, Bellville 7535, Cape Town, South Africa. 2 Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209, South Africa. 3 Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany AS CR, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic. 4 Ornamental and Fruit Tree Nursery Jan Holub s.r.o., Hvozdečko 7, 783 25, Bouzov, Czech Republic(1). 5 Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209, South Africa. Electronic address: rcpgd@ukzn.ac.za. Abstract Clonal propagation plays a critical integral role in the growth and success of a global multi-billion dollar horticulture industry through a constant supply of healthy stock plants. The supply chain depends on continuously improving the micropropagation process, thus, understanding the physiology of in vitro plants remains a core component. We evaluated the influence of exogenously applied cytokinins (CKs, N6-benzyladenine = BA, isopentenyladenine = iP, meta-topolin = mT, 6-(3-hydroxybenzylamino)-9-(tetrahydropyran-2-yl)purine = mTTHP) in Murashige and Skoog (MS)-supplemented media on organogenic response and accumulation of endogenous CK and indole-3-acetic acid (IAA) metabolites. The highest shoot proliferation (30 shoots/explant) was obtained with 20 μM mT treatment. However, the best quality regenerants were produced in 10 μM mT treatment. Rooting of Amelanchier alnifolia in vitro plantlets was observed at the lowest CK concentrations, with the highest root proliferation (3 roots/explant) in 1 μM mTTHP regenerants. Similar to the organogenic response, high levels of endogenous bioactive CK metabolites (free bases, ribosides, and nucleotides) were detected in mT and mTTHP-derived regenerants. The level of O-glucosides was also comparatively high in these cultures. All CK-treated plants had high levels of endogenous free IAA compared to the control. This may suggest an influence of CKs on biosynthesis of IAA. KEYWORDS: Auxins; Endogenous cytokinins; Micropropagation; Organogenesis; Saskatoon berry; Topolins