Bruce E. Haissig

Biology of adventitious root formation

Special Lecture: The Origin, Diversity, and Biology of Shoot-Borne Roots P.W. Barlow. The Commercial Importance of Adventitious Rooting: Commercial Application of Adventitious Rooting to Forestry G.A. Ritchie. Infrastructure for Research: Model Systems for Studying Adventitious Root Formation S.G. Ernst. Setting the Stage for Rooting: Novel Experimental Systems for Determining Cellular Competence and Determination D. Mohnen. Induction of Rooting: Auxin Metabolism and Adventitious Root Initiation D. Blakesley. Root Development and Plant Growth: Modeling Root System Morphology in Rice S. Morita, J. Abe. Special Chapter: A Historical Evaluation of Adventitious Rooting Research to 1993 B.E. Haissig, T.D. Davis. Epilogue: Research on Adventitious Rooting W.P. Hackett, J.R. Murray. 12 additional articles. Index.

A Historical Evaluation of Adventitious Rooting Research to 1993

Vegetative propagation of plants by rooting of cuttings (cuttage) was successfully used hundreds of years before there was any study, much less understanding, of the underlying biological processes. For some species, cuttage was old practice even in antiquity, as evidenced in the writings of Aristotle (384–322 B.C.), Theophrastus (371–287 B.C.) and Pliny the Elder (23–79 A.D.). But cuttage was never successful enough to fulfill all then-current public and commercial demands and it still is not [e.g, see chapter by Howard in this volume]. In addition, organ formation has long been a study area within plant morphogenesis (Went and Thimann, 1937), which has made adventitious rooting of academic botanical interest. Hence research on the fundamental biology of adventitious rooting began and continues.

Influence of indole-3-acetic acid on adventitious root primordia of Brittle Willow.

SummaryRemoval of the stem apex and certain leaves and axillary buds of brittle willows (Salix fragilis) was employed to limit the supply of endogenous auxin to adventitious root primordia during their formation, which occurs at predetermined sites. Limiting endogenous auxin by this surgical treatment resulted in reduced primordium initiation and, to a lesser degree, primordium growth in cell number. Root primordium cells in surgically treated plants differentiated into mature parenchyma after losing their meristematic character. Application of indole-3-acetic acid (IAA) to surgically treated plants partially overcame the effects of the surgical tretament, increasing root primordium initiation and growth by cell division. When IAA-2-14C was applied to surgically treated plants, label was detected in root primordium cells by means of autoradiography. Root primordium cells took up more label during the earliest stage of initiation than during a later stage of growth. The data indicate that the initiation of these primordia is more dependent on a supply of auxin than is their subsequent development. Further, the auxin apparently acts directly in the cells which initiate primordia.

Organ formation in vitro as applicable to forest tree propagation

Literature concerning the influences of auxins, adenine, kinetin, light, heat, time, age, and physical characteristics of the medium onin vitro organ formation by sterile seed-plant fragments is reviewed and integrated.

Development of Glyphosate-Tolerant Populus Plants through Expression of a Mutant aroA Gene from Salmonella Typhimurium

The development of a plant regeneration and transformation system for the poplar hybrid NC5339 (Populus alba x Populus grandidentata) is described. A binary armed strain of Agrobacterium tumefaciens harboring three chimeric gene fusions was used as a vector. Genetic transformation was confirmed through western blot analyses. Employing this system, we have introduced into Populus NC5339 a bacterial aroA gene which confers tolerance to the herbicide glyphosate. Expression of this foreign gene into Populus is discussed.