Auxin-cytokinin interaction and variations in their metabolic products in the regulation of organogenesis in two Eucomis species.
In the current study, we evaluated the effect of α-naphthaleneacetic acid (NAA) individually or in combination with different cytokinins (CKs) including benzyladenine (BA), meta-topolin (mT) and isopentenyladenine (iP) on organogenesis, auxin and CK content in Eucomis autumnalis subspecies autumnalis (EA) and Eucomis zambesiaca (EZ). These species were used as model plants due to their ornamental and medicinal properties. Three leaf explants were inoculated in screw-cap jars containing 30mL Murashige and Skoog (MS) media supplemented with 5μM NAA alone or in combination with 5μM CK (BA, mT or iP). After 10 weeks (EA) or 15 weeks (EZ), parameters including shoot and root growth as well as plant fresh weight were recorded. For analysis of auxin and CK content, whole plantlets were harvested, pooled and freeze-dried for the different treatments. In both species, shoot and root proliferation as well as plant biomass were generally higher when NAA was combined with the individual CK than in NAA or CK treatment. The highest concentration of indole-3-acetic acid (IAA, 619pmolg-1DW) and 2-oxindole-3-acetic acid (OxIAA, 2381pmolg-1DW) were observed in EA-treated with NAA alone while mT treatment (without NAA) had the most abundant indole-3-acetyl-l-aspartic acid (IAAsp, 904 and 582pmolg-1DW for EA and EZ, respectively) in both species. A significant concentration of total endogenous CK accumulated in both Eucomis regenerants from mT and mT+NAA when compared to the other treatments. The majority of the detected CKs were of the aromatic CK-type, mainly free bases. The potential physiological roles of these quantified phytohormones in relation to the observed morphological responses are discussed.
Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa.
Adeyemi O
AO
Aremu
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 and Institute of Experimental Botany AS CR, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
Lenka
L
Plačková
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 and Institute of Experimental Botany AS CR, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
Aleš
A
Pěnčík
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 and Institute of Experimental Botany AS CR, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
Ondřej
O
Novák
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 and Institute of Experimental Botany AS CR, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
Karel
K
Doležal
Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa. Electronic address: rcpgd@ukzn.ac.za.
Johannes
J
Van Staden
D000070357:Asparagaceae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D018533:Biomass; D001709:Biotechnology; D003583:Cytokinins / Q000008:administration & dosage / Q000378:metabolism*; D004347:Drug Interactions; D007210:Indoleacetic Acids / Q000008:administration & dosage / Q000378:metabolism*; D009280:Naphthaleneacetic Acids / Q000008:administration & dosage / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013045:Species Specificity
D003583:Cytokinins; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010937:Plant Growth Regulators; C034182:1-naphthaleneacetic acid
Asparagaceae; Indole-3-acetic acid; Ornamentals; Phytohormones; Rooting; meta-Topolin