Sepecial symposium: In vitro plant recalcitrance in vitro plant recalcitrance: An introduction

Summary In vitro recalcitrance is the inability of plant cells, tissues and organs to respond to tissue culture manipulations. With respect to plant regeneration, recalcitrance can be a major limiting factor for the biotechnological exploitation of economically important plant species and it can also impair the wider application of in vitro conservation techniques. This first paper introduces a compilation of Symposium papers, collectively entitled “Do we understand in vitro plant recalcitrance?”, presented at the 1999 Congress of the Society for In Vitro Biology. The Symposium reviewed recalcitrance in the context of genetic predeterminism, molecular markers and gene expression patterns, whole and explant physiology, stress physiology, habituation, neoplastic progression and plant cancer. The symposium contributors present fundamental and applied investigative approaches which have the potential to enhance our current understanding of in vitro recalcitrance and to assist in overcoming the problems associated with nonresponsive plant cultures. This introductory paper presents the general concept of recalcitrance in relation to whole-plant and explant physiology and considers basic aspects of tissue culture manipulations in the context of recalcitrance problems.