Papers Presented at a Symposium held May 8--11, 1989, at the Beltsville Agricultural Research Center (BARC), Beltsville, Maryland, U.S.A.

All the chapters of this book constitute the proceedings of the National Symposium entitled Rhizosphere Biotechnology/Microbes Retrospects and prospects held on 29-30 November, 2004, at Department of Botany, T.M. Bhagalpur University, Bhagalpur (Bihar). This book includes Special lectures, Review articles and Research papers in the form of Book chapters covering almost all aspects of focal theme of the symposium, which will be of immense utility to the researchers, P.G. students and to those working in allied field.

Plant Science, like the biological sciences in general, has undergone seismic shifts in the last thirty or so years. Of course science is always changing and metamorphosing, but these shifts have meant that modern plant science has moved away from its previous more agricultural and botanical context, to become a core biological discipline in its own right. However the sheer amount of information that is accumulating about plant science, and the difficulty of grasping it all, understanding it and evaluating it intelligently, has never been harder for the new generation of plant scientists or, for that matter, established scientists. And that is precisely why this Handbook of Plant Science has been put together. Discover modern, molecular plant sciences as they link traditional disciplines! Derived from the acclaimed Encyclopedia of Life Sciences! Thorough reference of up-to-the minute, reliable, self-contained, peer-reviewed articles – cross-referenced throughout! Contains 255 articles and 48 full-colour pages, written by top scientists in each field! The Handbook of Plant Science is an authoritative source of up-to-date, practical information for all teachers, students and researchers working in the field of plant science, botany, plant biotechnology, agriculture and horticulture.

To meet the food security needs of the 21st century, this book focuses on ecofriendly and sustainable production technologies based on plant growth promoting rhizobacteria (PGPR). It is estimated that the global population could increase to 9 billion by 2050. Further, the amount of land devoted to farming has decreased. Soil is a living entity, and is not only a valuable natural resource for agricultural and food security, but also for the preservation of all life processes. Agricultural productivity rests on the foundation of microbial diversity in the soil, and in recent years, PGPR have emerged as an important and promising tool for sustainable agriculture. The injudicious use of agrochemicals by farmers has created a range of negative impacts, not only threatening the environment, but also destroying useful microorganisms in the soil. The efficient use of PGPR reduces the need for these chemicals while simultaneously lowering production costs. In turn, increased yields could provide a more favourable environment and encourage sustainability. This book assesses the impacts of PGPR on crops, environmental and socio-economic sustainability, and demonstrates these ecofriendly technologies’ three critical advantages, namely (a) enhanced crop productivity, (b) reduced application of agrochemicals, and (c) increased incomes for farmers. Besides offering an economically attractive and ecologically sound means of augmenting the nutrient supply and combatting soil-borne pathogens, PGPR play an important part in boosting soil fertility, bioremediation and stress management for the development of ecofriendly and sustainable agriculture.

Abiotic and biotic stress factors, including drought, salinity, waterlog, temperature extremes, mineral nutrients, heavy metals, plant diseases, nematodes, viruses, and diseases, adversely affect growth as well as yield of crop plants worldwide. Plant growth-promoting microorganisms (PGPM) are receiving increasing attention from agronomists and environmentalists as candidates to develop an effective, eco-friendly, and sustainable alternative to conventional agricultural (e.g., chemical fertilizers and pesticide) and remediation (e.g., chelators-enhanced phytoremediation) methods employed to deal with climate change-induced stresses. Recent studies have shown that plant growth-promoting bacteria (PGPB), rhizobia, arbuscular mycorrhizal fungi (AMF), cyanobacteria have great potentials in the management of various agricultural and environmental problems. This book provides current research of biofertilizers and the role of microorganisms in plant health, with specific emphasis on the mitigating strategies to combat plant stresses.

Biochemistry of Metal Micronutrients in the Rhizosphere focuses on chemical factors and biological activities that control the uptake and translocation of essential metal micronutrients by plants and microorganisms. Emphasis is placed on current proposals describing the roles of microorganisms in controlling the biological activities of metal micronutrients in the rhizosphere. Coverage includes basic principles of siderophore-mediated Fe acquisition by microorganisms, siderophores as important regulators of Fe availability to plants and rhizosphere microorganisms, and microbial control of metal micronutrient supply to plants. The book evaluates plant uptake processes of Fe, Mn, and Zn in solution cultures and integrates this information with a rapidly developing understanding of rhizosphere events. Important consideration is given to the roles of metal ion chelation and soil chemistry in these biological activities. The current understanding of the biochemical events associated with Fe-deficiency in plants is discussed, including how these activities mediate micronutrient availability to both plants and soil microorganisms. This unique mixture of detailed coverage of the events that control biological activities of Fe, Mn, and Zn in the rhizosphere makes this book an essential reference.

This book presents a detailed discussion on the direct interactions of plants and microorganisms in the rhizosphere environment. It includes fifteen chapters, each focusing on a specific component of plant-microbe interactions, such as the influence of plants on the root microbiome, and the downstream effects of rhizosphere microbial dynamics on carbon and nutrient fluxes in the surroundings. As such, the book helps readers gain a better understanding of diversity above the ground, and its effect on the microbiome and its functionality.

The rhizosphere, the soil volume, which is directly affected by root activity, is an important hot spot for a multitude of biotic and abiotic processes. Carbon transfer from plants to microorganisms and to soil takes place in these small volumes around living roots, creating chemical gradients and zones of microbial activity over distinct temporal and spatial scales. Hydraulic and biogeochemical properties of the rhizosphere and the formation of complex three-dimensional structures such as micro- and macroaggreates in turn, result from complex feedbacks between physical, chemical and biological processes. The aim of this Research Topic is to advance our understanding of rhizosphere interactions by collating 16 original contributions across disciplines, including original research, reviews and specific methods on the processes taking place in the rhizosphere, to shed new light on one of the most important interfaces for the diversity of life on earth.

This contributed volume explores how plant growth-promoting rhizobacterias (PGPR) provide a wide range of benefits to the plant. Further, it discusses the key roles PGPR play in nutrient acquisition and assimilation, improved soil texture, secreting, and modulating extracellular molecules. The book outlines how plant secondary metabolites are natural sources of biologically active compounds used in a wide range of applications, and surveys the significant role of volatile organic compounds (VOCs) in plant communication by mediating above- and below-ground interactions between plants and the surrounding organisms. This volume compiles research from leading scientists from across the globe, linking the translation of basic knowledge to innovative applied research. The book focuses on the following three categories: 1) understanding the secondary metabolites produced by PGPR, the signaling mechanisms and how they affect plant growth, 2) the plausible role of volatile organic compounds produced by PGPR, their role and the signaling mechanism for plant growth promotion, and 3) Applications of VOCs and secondary metabolites of PGPR for seed germination, plant growth promotion; stress tolerance and in-plant health and immunity.

Plants create a dynamic micro-biosphere in the soil, around the roots, called as ‘rhizosphere’, which harbors diverse number of microorganisms for sustaining their growth and development. A soil with diverse and multi-traits microbial communities is considered healthy to enhance crop productivity. In the last decades, rhizosphere biology has gained attention due to unraveling of new mechanisms, processes and molecules in the rhizosphere that contributes towards the promotion of plant productivity. The rhizospheric microbes and associated processes are being utilized for harnessing potential of soils in effective and sustainable functioning in the agro-ecosystems. Broadly, the book discusses rhizospheric microbes and their role in modulating functions of soil and crop plant. Specifically, it highlights conventional and modern aspects of rhizosphere microbes such as – microbiome in the rhizosphere, microbes as an indicator and promoter of soil health, rhizosphere microbes as biofertilizer, biostimulator and biofortifyer, microbial signaling in the rhizosphere, recent tools in deciphering rhizobiome, and regulatory mechanisms for commercialization of biofertilizer, biopesticide and biostimulator. The book is useful for agriculture scientist, biotechnologist, plant pathologist, mycologist, and microbiologist, farming community, scientist of R&D organization, as well as teaching community, researcher and student and policy maker.