*3.1. Principles for Starting In Vitro Micropropagation of Syngonium podophyllum Schott. Cv. 'White Butterfly'*

*Syngonium podophyllum* Schott. cv. 'White butterfly' was studied as a representative of the Araceae family in Romania for 8 years, between 1996 and 2004. The objective was to develop a micropropagation protocol for industrial purposes, initiated in 1996 as an important goal to increase the indoor plant trade offerings of the Glasshouse Complex Codlea in Brasov County, Romania. This complex functioned for 20 years between 1988 and 2008, after which it was forced to close due to a nationwide economic crisis. It should be noted that the profit of the state-owned company was outstanding, and the decline was mainly the result of political issues [39,40].

In implementing an industrial micropropagation protocol for *Syngonium*, we followed three major principles: (1) to maintain long-term genetic stability for all micropropagation stages, (2) to provide the most cost-effective technology, and (3) to constantly upgrade the technology according to the latest scientific achievements.

To adhere to the first principle, based on our laboratory experience, we used (a) meristem culture to avoid contamination by viruses and other microorganisms (this protocol had already been implemented for carnations, among other species), (b) the simplest and cheapest possible culture media and avoidance of long-term propagation (i.e., by using

low hormone quantities and avoiding mutagenesis), and (c) a very rigorous control of technological factors—such as light intensity and photoperiod, day/night temperature, humidity, air sterilization, and ventilation—similar to existing technology for carnation micropropagation, and for the entire workflow from laboratory to greenhouse.

The second principle aimed to obtain the simplest and most cost-effective industrial protocol possible based on the available reagents in the laboratory and greenhouse, as well as the skills developed by laboratory personnel. A highly rigorous control system was implemented for all technological factors (e.g., light intensity and photoperiod, day/night temperature, humidity, air sterilization, ventilation, electricity supply, heating/cooling during the winter/summer seasons, and disease/pest control in the greenhouse). We also applied rigorous control of all personnel activities and created bypass-type plans for potential technological remedies (e.g., virus detection in case of infection in the laboratory, disease/pest control in the greenhouse, contingencies in case of delays to the import of reagents or other materials).

The third principle, referring to the constant upgrading of technology according to the latest scientific achievements, was implemented with the limitation of restricted access to the newest scientific information due to prohibitive costs. We should also mention the total lack of access to the scientific journals published between 1996 and 2000, during which time the scientific literature library of the Romanian Academy was not open-access. In this regard, three relevant peer-reviewed scientific articles were published in the English language on subjects related to the callogenesis and micropropagation of the species [31–33], which scientifically substantiated a Ph.D. thesis that was publicly defended after six years of research in 2002 [34].

These principles discussed above are consistent with those applied and discussed by other authors [41,42].

In order to develop a completely new micropropagation protocol for newly introduced ornamental species, it was considered relevant at the time to devise some experimental tests for ensuring the most appropriate balance between auxin and cytokinin, as well as the best mineral and vitamin compositions for use in the culture media. In this case, it was preferred to start using the plant growth regulators already available in our laboratory, such as benzyl-aminopurine (BAP), indole-3-acetic acid (IAA), naphthyl acetic-acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D). All of the other reagents (i.e., minerals, vitamins, sucrose, and agar) were provided by Merck, Sigma, and Difco, and they were already in use in our laboratory in the industrial protocol for carnation micropropagation (*Dianthus* sp.), as well as other species, cultivars, and hybrids (i.e., *Gerbera x hybrida* Hort., *Chrysanthemum* × *morifolium* (Ramat.) Hemsl., *Nephrolepis exaltata var. hirsutula* (*G. Forst.*) *Baker*, sp., *Cymbidium floribundum* Lindl., *Saintpaulia ionantha* H.Wendl., *Sequoia gigantea* Endl., *Solanum tuberosum* L.). Based on the experience of our laboratory, these reagents were considered to be the most reliable in terms of costs as well as for midterm preservation. The simplified micropropagation protocol was published in *Aroideana*—the Journal of the International Aroid Society—in 2004 [33].
