Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2014
Publication Date: 6/5/2014
Citation: Niedz, R.P., Hyndman, S.E., Evens, T.J., Weathersbee, A.A. 2014. Mineral nutrition and in vitro growth of Gerbera hybrida (Asteraceae). In Vitro Cellular and Developmental Biology Plants. 50:458-470. Interpretive Summary: Gerbera daisy is one of the most popular flowering ornamentals worldwide and is sold as bedding and potted plants and cut flowers. Gerbera daisies are propagated by plant tissue culture because conventional horticultural propagation methods, cuttings or division of clumps, are sometimes not sufficient to produce the large numbers of plants required. Proper mineral nutrition is fundamental for growing healthy plants and is the most basic component of a plant tissue culture medium. Therefore, understanding the effects of the mineral nutrients and how they interact with other medium components such as plant growth regulators, vitamins, carbon sources, and substrate can only improve our ability to successfully culture plant cells, tissues, and organs in vitro. We report a series of experiments that examine the effects of mineral nutrients on the growth of gerbera daisy in tissue culture including overall plant quality, number of shoots, number of leaves, and size of shoots. A large data set was created on the effects of groups of fertilizer salts, individual salts of micronutrients (copper, manganese, zinc, and iron), and the specific mineral nutrient ions nitrate, ammonium, and potassium on these important plant tissue culture responses. The data set should be useful for developing improved mineral nutrient formulations for the tissue culture of gerbera daisy.
Technical Abstract: Gerbera hybrida (G. jamesonii x G. viridifolia) or gerbera daisy is one of the most popular flowering ornamental plants worldwide and is sold as bedding, potted plants, and cut flowers. Gerbera daisies are propagated by in vitro culture because conventional propagation methods, by division of clumps or cuttings, are sometimes not sufficient to produce the large numbers of plants required. Most of the research on mineral nutrient effects on in vitro growth of gerbera has compared various basal media formulations. This work examined mineral nutrient effects in more detail. Methodology/Principal Findings: Four types of experiments were conducted to quantify the effects of mineral nutrients on four in vitro growth response (quality, shoot number, leaf number, and shoot height) of gerbera and included groups of mineral nutrients (macros, mesos, and Fe/EDTA), individual salts (CuSO4.5H2O, MnSO4.4H2O, ZnSO4.7H2O, and FeSO4/EDTA), and the specific ions NO3-, NH4+, and K+. Experiments included mixture-amount designs to separate the effects of proportion and concentration, essential for understanding mineral nutrient effects. Highly significant effects were observed in all experiments and revealed that the mineral nutrients with the largest effects varied between the four growth responses. For example, leaf number was strongly affected by the macro nutrient group in one experiment and NH4+ and K+, which were in the macro nutrient group, in the NO3-/NH4+/K+ ion-specific experiment; whereas, quality was strongly affected by the micro nutrients ZnSO4 and FeSO4/EDTA. Conclusions/Significance: Because mineral nutrient effects varied significantly with the response measured, defining an appropriate formulation requires a clear definition of “optimal” growth. It is likely that the definition will vary depending on the needs of the grower.