This text/reference is broadly based, covering four basic areas: physiology and metabolism of nitrogen, phosphorus and sulphur by fungi; the role of these minerals in pathogenic relationships with plants; their role in mutualistic relationships with plants; and the role of saprotrophic fungi in cycling of the elements through ecosystems. Annotation.
This book promotes further understanding of the contribution that fungi make to the biogeochemical cycling of elements, the chemical and biological mechanisms involved, and their environmental and biotechnological significance.
The roots of most plants are colonized by symbiotic fungi to form mycorrhiza, which play a critical role in the capture of nutrients from the soil and therefore in plant nutrition. Mycorrhizal Symbiosis is recognized as the definitive work in this area. Since the last edition was published there have been major advances in the field, particularly in the area of molecular biology, and the new edition has been fully revised and updated to incorporate these exciting new developments. - Over 50% new material - Includes expanded color plate section - Covers all aspects of mycorrhiza - Presents new taxonomy - Discusses the impact of proteomics and genomics on research in this area
For this third volume of the series Soil Biology, internationally renowned scientists shed light on the significant roles of microbes in soil. Key topics covered include: bioerosion, humification, mineralization and soil aggregation; Interactions in the mycorrhizosphere; microbes and plant nutrient cycling; Microbes in soil surface or toxic metal polluted soils; Use of marker genes and isotopes in soil microbiology, and many more.
Phosphorus (P) is a finite resource which is essential for life. It is a limiting nutrient in many ecosystems but also a pollutant which can affect biodiversity in terrestrial ecosystems and change the ecology of water bodies. This book collects the latest information on biological processes in soil P cycling, which to date have remained much less understood than physico-chemical processes. The methods section presents spectroscopic techniques and the characterization of microbial P forms, as well as the use of tracers, molecular approaches and modeling of soil-plant systems. The section on processes deals with mycorrhizal symbioses, microbial P solubilization, soil macrofauna, phosphatase enzymes and rhizosphere processes. On the system level, P cycling is examined for grasslands, arctic and alpine soils, forest plantations, tropical forests, and dryland regions. Further, P management with respect to animal production and cropping, and the interactions between global change and P cycling, are treated.
`The fundamental problem the world faces today, is the rapidly increasing pressure of population on the limited resources of the land. To meet the ever increasing demands of expanding populations, agricultural production has been raised through the abundant use of inorganic fertilizers, the adoption of multicropping systems and liberal application of chemical pesticides (fungicides, bactericides, etc. ). Though the use of chemicals has increased the yield dramatically, it has also resulted in the rapid deterioration of land and water resources apart from wastage of scarce resources. This has adversely affected the biological balance and lead to the presence of toxic residues in food, soil and water in addition to imposing economic constraints on developing countries.' (From the Preface) Mycorrhizal Biology addresses the global problem of land degradation and the associated loss of soil productivity and decline in soil quality caused by exploitative farming practices and poor management in developing countries, and the far reaching socio-economic and ecological consequences of its impact on agricultural productivity and the environment. In the light of a need for sustainable development, a new system of productive agriculture, to ensure the efficient management of agricultural inputs for long term high crop productivity with minimum damage to the ecological and socio-economic environment is essential. The management of mycorrhizal fungi will form a significant part of such a system and this work investigates the key association of plant roots with mycorrhizal fungi, known to benefit plants under conditions of nutritional and water stress and pathogen challenge and analyses the developments in our understanding of the genetic loci that govern mycorrhiza formation.
Fleshy Fruits are a late acquisition of plant evolution. In addition of protecting the seeds, these specialized organs unique to plants were developed to promote seed dispersal via the contribution of frugivorous animals. Fruit development and ripening is a complex process and understanding the underlying genetic and molecular program is a very active field of research. Part of the ripening process is directed to build up quality traits such as color, texture and aroma that make the fruit attractive and palatable. As fruit consumers, humans have developed a time long interaction with fruits which contributed to make the fruit ripening attributes conform our needs and preferences. This issue of Frontiers in Plant Science is intended to cover the most recent advances in our understanding of different aspects of fleshy fruit biology, including the genetic, molecular and metabolic mechanisms associated to each of the fruit quality traits. It is also of prime importance to consider the effects of environmental cues, cultural practices and postharvest methods, and to decipher the mechanism by which they impact fruit quality traits. Most of our knowledge of fleshy fruit development, ripening and quality traits comes from work done in a reduced number of species that are not only of economic importance but can also benefit from a number of genetic and genomic tools available to their specific research communities. For instance, working with tomato and grape offers several advantages since the genome sequences of these two fleshy fruit species have been deciphered and a wide range of biological and genetic resources have been developed. Ripening mutants are available for tomato which constitutes the main model system for fruit functional genomics. In addition, tomato is used as a reference species for climacteric fruit which ripening is controlled by the phytohormone ethylene. Likewise, grape is a reference species for non-climacteric fruit even though no single master switches controlling ripening initiation have been uncovered yet. In the last period, the genome sequence of an increased number of fruit crop species became available which creates a suitable situation for research communities around crops to get organized and information to be shared through public repositories. On the other hand, the availability of genome-wide expression profiling technologies has enabled an easier study of global transcriptional changes in fruit species where the sequenced genome is not yet available. In this issue authors will present recent progress including original data as well as authoritative reviews on our understanding of fleshy fruit biology focusing on tomato and grape as model species.
Black & white print. Concepts of Biology is designed for the typical introductory biology course for nonmajors, covering standard scope and sequence requirements. The text includes interesting applications and conveys the major themes of biology, with content that is meaningful and easy to understand. The book is designed to demonstrate biology concepts and to promote scientific literacy.
Nitrogen (N) is a mineral nutrient that is essential for the normal growth and development of plants that is required in the highest quantity. It is an element of nucleic acids, proteins, and photosynthetic metabolites, therefore crucial for crop growth and metabolic processes. Recently, it was estimated that N fertilizers could meet the 48% demand of the world’s population. However, overuse and misuse of N fertilizers raised environmental concerns associated with N losses by nitrous oxide (N2O) emissions, ammonia (NH3) volatilization, and nitrate (NO3−) leaching. For instance, NH3 is a pollutant in the atmosphere, N2O is a greenhouse gas that has a warming potential 298 times higher than CO2 and contributes to ozone depletion, and NO3− causes eutrophication of water bodies. Agricultural practices account for about 90% of NH3 and 70% of N2O anthropogenic emissions worldwide. The efficient use of N chemical fertilizers can be attained through cultural and agronomic practices. Nitrogen use efficiency (NUE) is an important trait that has been studied for decades in different crops. The grain production or economic return from the per unit supply of N fertilizer simply explained the NUE. Several definitions were suggested by different researchers. NUE can be defined as the product of N uptake efficiency (NUpE) and N utilization efficiency (NUtE). An increase in NUE increases the yield, biomass, quality, and quantity of crops. N is generally applied as chemical fertilizer to the soil, whereas a small amount is added to some crops like grain legumes through the fixation process. On the other hand, crop plants take N through the root system in the form of nitrate or ammonium which is thereby used in different metabolic processes. A number of studies have been conducted to increase the NUE in different crops and it has been indicated that NUE can be improved by agronomic, physiological, biochemical, breeding as well as molecular approaches. Nitrogen is the main limiting nutrient after carbon, hydrogen, and oxygen for the photosynthetic process, phyto-hormonal and proteomic changes, and the growth-development of plants to complete their lifecycle. Excessive and inefficient use of N fertilizer results in enhanced crop production costs and atmospheric pollution. Atmospheric nitrogen (71%) in the molecular form is not available for the plants. For the world's sustainable food production and atmospheric benefits, there is an urgent need to upgrade nitrogen use efficiency in the agricultural farming system. Nitrogen losses are too high, due to excess amount, low plant population, poor application methods, etc., which can go up to 70% of total available nitrogen. These losses can be minimized up to 15–30% by adopting improved agronomic approaches such as optimal dosage of nitrogen, application of N by using canopy sensors, maintaining plant population, drip fertigation, and legume-based intercropping. Therefore, the major concern of modern days is to save economic resources without sacrificing farm yield as well as the safety of the global environment, i.e. greenhouse gas emissions, ammonium volatilization, and nitrate leaching.
