This textbook is clearly structured with fourteen richly illustrated chapters and practical examples for easy understanding and direct implementation. The methods and findings developed in the authors' group are presented in detailed, revised chapters. Readers will find valuable updates on the molecular basis of biotechnological processes, secondary metabolite production and genetic engineering. In addition, the basic principles of important biotechnologies, as well as examples of specially designed crops that deliver improved productivity under stress conditions, are presented. This second edition sets the direction for future research on the basic aspects of plant tissue culture and its applications in the fields of secondary metabolite production and genetic engineering. It provides both general and specific information for students, teachers, academic researchers and industrial teams who are interested in new developments in plant tissue culture and its applications.

It must have been some feeling of frustration invoked by the genus loci of big conferences which brought Don Dougall, Mike Fowler, and me over a cup of coffee to think of organizing a small meeting on cell culture metabol ism. The basic aim was to bring people working on "primary metabolism" and those who work on "secondary metabolism" to interact with each other, hopefully to induce some new approaches to utilize the cell culture technique more efficiently in basic research and in its practical application. The out come of this was the small symposium at SchloE Rauischholzhausen near GieEen (Germany), and the reader of this small volume of articles on topics discussed will judge to what extent this aim was realized. Although F.e. Steward was unable to attend the meeting, we were happy that he contributed a review on some important turning points of the cell culture method in the past, and at the end of the book some participants of the meeting attempted some prognosis on possible future developments, summarized by Mike Fowler. It was the wish of our publisher to organize the contributions as a summary of the major topics of research of the individual groups represented at the meeting. Due to this, some readers will certainly feel that important areas of research in the cell culture field are missing. This is regrettable, but space had to be limited to keep this volume at a reasonable price."

The adv antages of those systems are counterbalanced by some important dis- vantages. For one, in heterotrophic and mixotrophic systems high concentrations of organic ingredients are required in the nutrient medium (particularly sugar at 2% or more), associated with a high risk of microbial contamination. How, and to which extent this can be avoided will be dealt with in Chapter 3. Other disadvantages are the difficulties and limitations of extrapolating results based on tissue or cell c- tures, to interpreting phenomena occurring in an intact plant during its development. It has always to be kept in mind that tissue cultures are only model systems, with all positive and negative characteristics inherent of such experimental setups. To be realistic, a direct duplication of in situ conditions in tissue culture systems is still not possible even today in the 21st century, and probably never will be. The organization of the genetic system and of basic cell structures is, however, essentially the same, and therefore tissue cultures of higher plants should be better suited as model s- tems than, e.g., cultures of algae, often employed as model systems in physiological or biochemical investigations. The domain cell and tissue culture is rather broad, and necessarily unspecif ic. In terms of practical aspects, basically five areas can be distinguished (see Figs. 1.1, 1.2 ), which here shall be briefly surveyed before being discussed later at length.

The adv antages of those systems are counterbalanced by some important dis- vantages. For one, in heterotrophic and mixotrophic systems high concentrations of organic ingredients are required in the nutrient medium (particularly sugar at 2% or more), associated with a high risk of microbial contamination. How, and to which extent this can be avoided will be dealt with in Chapter 3. Other disadvantages are the difficulties and limitations of extrapolating results based on tissue or cell c- tures, to interpreting phenomena occurring in an intact plant during its development. It has always to be kept in mind that tissue cultures are only model systems, with all positive and negative characteristics inherent of such experimental setups. To be realistic, a direct duplication of in situ conditions in tissue culture systems is still not possible even today in the 21st century, and probably never will be. The organization of the genetic system and of basic cell structures is, however, essentially the same, and therefore tissue cultures of higher plants should be better suited as model s- tems than, e.g., cultures of algae, often employed as model systems in physiological or biochemical investigations. The domain cell and tissue culture is rather broad, and necessarily unspecif ic. In terms of practical aspects, basically five areas can be distinguished (see Figs. 1.1, 1.2 ), which here shall be briefly surveyed before being discussed later at length.