Charles E. Hess Department of Environmental Horticulture University of California Davis, CA 95616 Research in the biology of adventitious root formation has a special place in science. It provides an excellent forum in which to pursue fundamental research on the regulation of plant growth and development. At the same time the results of the research have been quickly applied by commercial plant propagators, agronomists, foresters and horticulturists (see the chapter by Kovar and Kuchenbuch, by Ritchie, and by Davies and coworkers in this volume). In an era when there is great interest in speeding technology transfer, the experiences gained in research in adventitious root formation may provide useful examples for other areas of science. Interaction between the fundamental and the applied have been and continue to be facilitated by the establishment, in 1951, of the Plant Propagators' Society, which has evolved into the International Plant Propagators' Society, with active programs in six regions around the world. It is a unique organization which brings together researchers in universities, botanical gardens and arboreta, and commercial plant propagators. In this synergistic environment new knowledge is rapidly transferred and new ideas for fundamental research evolve from the presentations and discussions by experienced plant propagators. In the past 50 years, based on research related to the biology of adventitious root formation, advances in plant propagation have been made on two major fronts.

The book ‘Root Biology’ written by experts in the field, covers latest research on cellular, genetic, physiological and ecological developmental facets of root growth as well as the interaction of root with an array of microbes whether for the establishment of symbiosis, increasing plant growth or protecting plant from pathogens/attackers. Plant roots provide an excellent model to study physiological, developmental and metabolic processes at a system level. Root system architecture - an excellent creation of nature, is closely interconnected with the availability of soil nutrients. Several strategies including biotechnological interventions are gaining interest and importance for sustainable food production and enhanced resource acquisition. Such strategies have largely focused on root traits for efficient utilization of soil resources. The biotechnological application of root biology is expected to promote the production of food while maintaining ecologically and economically sustainable production systems. With a fortune of information on technical and experimental aspects useful in the laboratory, this extensive book is a valuable resource for researchers, academician and students in the broad field of microbiology, plant and fungal biology.

This volume illustrates the complex root system, including the various essential roles of roots as well as their interaction with diverse microorganisms localized in or near the root system. Following initial chapters describing the anatomy and architecture as well as the growth and development of root systems, subsequent chapters focus on the various types of root symbiosis with bacteria and fungi in the rhizosphere. A third section covers the physiological strategies of roots, such as nitrate assimilation, aquaporins, the role of roots in plant defense responses and in response to droughts and salinity changes. The book’s final chapters discuss the prospects of applied engineering of roots, i.e., inventing new root structures or functions through genetic modification, but also with conventional breeding and manipulation of root symbionts. The budding field of root engineering is expected to promote a second green revolution.

The third edition of a standard resource, this book offers a state-of-the-art, multi-disciplinary presentation of plant roots. It examines structure and development, assemblage of root systems, metabolism and growth, stressful environments, and interactions at the rhizosphere. Reflecting the explosion of advances and emerging technologies in the field, the book presents developments in the study of root origin, composition, formation, and behavior for the production of novel pharmaceutical and medicinal compounds, agrochemicals, dyes, flavors, and pesticides. It details breakthroughs in genetics, molecular biology, growth substance physiology, biotechnology, and biomechanics.

Biology for AP® courses covers the scope and sequence requirements of a typical two-semester Advanced Placement® biology course. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology for AP® Courses was designed to meet and exceed the requirements of the College Board’s AP® Biology framework while allowing significant flexibility for instructors. Each section of the book includes an introduction based on the AP® curriculum and includes rich features that engage students in scientific practice and AP® test preparation; it also highlights careers and research opportunities in biological sciences.

This book provides up-to-date knowledge of root biology. Most plants have roots, which anchor the plant in the soil and physically support the above-ground parts of the plant. In addition, roots absorb water and nutrients from the soil and transport this to the shoot. Roots grow by cell proliferation in the meristem in the root tip. The cells differentiate into the epidermis, cortex, and stele. Water and nutrients are absorbed through the cell membrane of the epidermis and are transported to the above-ground parts via xylem vessels. The root growth and functions are affected by various abiotic and biotic conditions, such as levels of water, salt, acid stresses, and presence of soil diseases. However, some beneficial microorganisms such as rhizobia and mycorrhizal fungi help plant growth.

This detailed volume provides diverse elegant methods, complemented with existing protocols, which are optimized for the current needs in plant root biology as well as for use in plant species other than Arabidopsis thaliana. The collection covers methods ranging from genetic screens, phenotypic analysis, and cell biology methods to systems biology tools and genome-wide approaches. The collection contains a range of complexity from fundamental methods for quantification of different root developmental processes to complex methods that require sophisticated equipment. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Root Development: Methods and Protocols serves as a valuable tool for plant biologists specialized in root development, from beginners to experienced researchers in the field.

"Reprinted from Plant and soil, volume 274 (2005)."

The understanding of biological complexity has been greatly facilitated by cross-disciplinary, holistic approaches that allow insights into the function and regulation of biological processes that cannot be captured by dissecting them into their individual components. In addition, the development of novel tools has dramatically increased our ability to interrogate information at the nucleic acid, protein and metabolite level. The integration and interpretation of disparate data sets, however, still remain a major challenge in systems biology. Roots provide an excellent model for studying physiological, developmental, and metabolic processes. The availability of genetic resources, along with sequenced genomes has allowed important discoveries in root biochemistry, development and function. Roots are transparent, allowing optical investigation of gene activity in individual cells and experimental manipulation. In addition, the predictable fate of cells emerging from the root meristem and the continuous development of roots throughout the life of the plant, which permits simultaneous observation of different developmental stages, provide ideal premises for the analysis of growth and differentiation. Moreover, a genetically fixed cellular organization allows for studying the utilization of positional information and other non-cell-autonomous phenomena, which are of utmost importance in plant development. Although their ontogeny is largely invariant under standardized experimental conditions, roots possess an extraordinary capacity to respond to a plethora of environmental signals, resulting in distinct phenotypic readouts. This high phenotypic plasticity allows research into acclimative and adaptive strategies, the understanding of which is crucial for germplasm enhancement and crop improvement. With the aim of providing a current snapshot on the function and development of roots at the systems level, this Research Topic collated original research articles, methods articles, reviews, mini reviews and perspective, opinion and hypotheses articles that communicate breakthroughs in root biology, as well as recent advances in research technologies and data analysis.