Antioxidants And Reactive Oxygen Species In Plants by Nicholas Smirnoff (Biological Science: Blackwell Publishers) Reactive oxygen species (ROS) are produced during the interaction of metabolism with oxygen. As ROS have the potential to cause oxidative damage by reacting with biomolecules, research on ROS has concentrated on the oxidative damage that results from exposure to environmental stresses and on the role of ROS in defense against pathogens. However, more recently, it has become apparent that ROS also have important roles as signaling molecules. A complex network of enzymatic and small molecule antioxidants controls the concentration of ROS and repairs oxidative damage, and research is revealing the complex and subtle interplay between ROS and antioxidants in controlling plant growth, development and response to the environment.
This book covers these new developments, generally focussing on molecular and biochemical details and providing a point of entry to the detailed literature. It is directed at researchers and professionals in plant molecular biology, biochemistry and cell biology, in both the academic and industrial sectors.
Reactive oxygen species (ROS), which include superoxide, hydrogen peroxide and the hydroxyl radical, are produced during the interaction of metabolism with oxygen. ROS have the potential to cause oxidative damage by reacting with biomolecules. Accordingly, the emphasis of research on ROS has been on the oxidative damage that results from exposure to environmental stresses and on the role of ROS in defense against pathogens. More recently, it has become apparent that ROS have important roles as signaling molecules that contribute to the control of plant development and to the sensing of the external environment. Complex networks of enzymatic and small molecule antioxidants control the concentration of ROS and repair oxidative damage. Interest in the function of small molecule antioxidants such as tocopherols (vitamin E), glutathione and ascorbic acid (vitamin C) is increasing, now that the details of their biosynthetic pathways have been uncovered. This research is revealing the complex and subtle interplay between ROS and antioxidants in controlling plant growth, development and response to the environment.The book covers these new developments through a series of in-depth chapters, but it also provides, in one place, an overview of the subject for those outside the research area. The first six chapters cover the synthesis and function of antioxidants (glutathione, proteins involved in thiol homeostasis, ascorbate, tocopherol, carotenoids, phenolic compounds and catalase). Many of these antioxidants are important in the human diet, which provides additional impetus to understand their metabolism in order to manipulate their synthesis more effectively. The next three chapters consider the role of ROS in signaling, developmental processes and cell wall biochemistry. The final two chapters consider photosynthesis, which is a major source of ROS in leaves, and response to ozone, which has provided a useful model system for understanding the complex interplay of responses made by plants to ROS and oxidative stress. The subject matter is generally focused on the molecular and biochemical details, as these have provided the basis for the large increase in research activity on ROS and antioxidants over the last decade. The antioxidant network is an ideal candidate for investigation on the genome-wide scale, using functional genomics and systems biology tools.
Plant Abiotic Stress edited by Matthew A. Jenks, Paul M. Hasegawa (Biological Sciences: Blackwell Publishers) Over the past decade, our understanding of plant adaptation to environmental stress, including both constitutive and inducible determinants, has grown considerably. This book focuses on stress caused by the inanimate components of the environment associated with climatic, edaphic and physiographic factors that substantially limit plant growth and survival. Categorically these are abiotic stresses, which include drought, salinity, non-optimal temperatures and poor soil nutrition. Another stress, herbicides, is covered in this book to highlight how plants are impacted by abiotic stress originating from anthropogenic sources. Indeed, it is an important consideration that, to some degree, the impact of abiotic stress is influenced by human activities. The book also addresses the high degree to which plant responses to quite diverse forms of environmental stress are interconnected. Thus the final two chapters uniquely describe the ways in which the plant utilizes and integrates many common signals and subsequent pathways to cope with less favorable conditions. The many linkages between the diverse stress responses provide ample evidence that the environment impacts plant growth and development in a very fundamental way.
The unquestionable importance of abiotic stress to world agriculture is demonstrated by the fact that altogether abiotic factors provide the major limitation to crop production worldwide. For instance, Bray et al. (2000) estimates that 5I—82% of the potential yield of annual crops is lost due to abiotic stress. Another example is the increasing use of aquifer-based irrigation by farmers worldwide, which poses a serious threat to the long-term sustainability of world agricultural systems. Over-utilization of these dwindling water supplies is leading to an ever-enlarging area in which productive farming itself has ceased or is threatened. With increasing irrigation world-wide comes the threat of increased salinization of field soils and, just as aquifer loss is shrinking crop yield. so soil salinization due to irrigation has, and will increasingly, reduce crop production in many parts of the world. Another major limitation to expansion of the production of traditional field crops is the problem of non-optimal temperatures, with conditions being either too cold for efficient crop production in the far northern and southern regions of the globe, or too warm in the more equatorial regions. Degradation of the soil by various factors (including anthropogenic) is also increasingly limiting crop yield, and so use of new crops with enhanced resistance to drought, salinity, sub- and supra-optimal temperatures, poor soil nutrient status and anthropogenic factors would benefit agriculture globally by reducing the use of groundwater resources and expanding the productivity of crops on existing and new lands.
The advent of new technologies
for the efficient identification of genetic determinants involved in plant
stress adaptation, fostered especially by the use of molecular genetics and high
throughput transcriptome, proteome, metabolome and ionome profiling methods,
has opened a door to exciting new approaches and applications for understanding
the mechanisms by which plants adapt to abiotic stress, and should ultimately
result in the production of new and improved stress-tolerant crops. This book
seeks to summarize the large body of current knowledge about cellular and
organismal mechanisms of tolerance to stress. Nine chapters written by leading
scientists involved in plant abiotic stress research worldwide provide
comprehensive coverage of the major factors impacting world crop production.
While modifications to the environment (like increasing use of irrigation,
agrichemicals or cultivation) or the expansion of farming into undisturbed lands
poses an obvious risk to natural ecosystems, simple genetic changes to crops
offer a relatively safe means of increasing yield at a minimal cost to the
environment and the farmer. The material presented in this book emphasizes
fundamental genetic, physiological, biochemical, and ecological knowledge of
plant abiotic stress, which may lead to both traditional and biotechnological
applications that result in improved crop performance in stressful environments.
The book is directed at researchers and professionals in plant physiology, cell biology and molecular biology, in both the academic and industrial sectors.
Plant by Janet Martinelli (DK) From cultivating plants that are on the international endangered list or already extinct in the wild, to avoiding invasive species, gardeners can play a vital role in conservation. A groundbreaking reference for both plant enthusiasts and gardeners, Plant is a new-generation encyclopedia designed to provide environmental and horticultural information so that gardeners can make the right decisions about what to grow in their gardens. The planet is poised on the brink of a modern extinction episode, says Janet Marinelli, editor-in-chief of the new book PLANT, "that would rival anything in evolutionary history, including the demise of the dinosaurs 65 million years ago." Marinelli explained, "If current trends continue, two-thirds of all plant species will disappear before the end of the 21st century — more than 55 percent of conifers, 52 percent of cycads, 38 percent of cacti, about a third of all members of the lily family, and almost all 800 orchid species are at risk for extinction in the coming decades." But the good news is that "as gardeners, we can play a very personal and important role in the survival of these beautiful and fascinating creatures."
Written by an international team of botanists, PLANT showcases some 2,000 of the planet's rarest and most imperiled plant species. A groundbreaking reference, this new-generation encyclopedia is designed to provide environmental and horticultural information for those concerned about plant extinction. While traditional gardeners' reference books have shown how to grow plants without explaining the reasons for their particular care, PLANT takes a new approach by detailing each plant's provenance, helping readers create a better garden with plants appropriate to one's environment. As well as the origins and native habitat of every plant, the book includes every detail of their potential benefit and how they can be cultivated responsibly.
More than a simple plant encyclopedia, some of the controversial topics discussed in this groundbreaking book include:
We might think of gardeners as a fairly harmless group of plant-loving people, however they hold a huge amount of power in determining the future of our planet's plant life. The gardener has the potential to be a plant's greatest friend or its greatest enemy. Ironically, it is man's love of plants that has in the past, and could in the future, lead to the extinction of many species. Whether unwitting or unscrupulous, gardeners buy plants every year that have been dug from their native areas worldwide. These purchases dramatically threaten to deplete — or even to wipe out — whole populations.
On the positive side, there is much that the ordinary gardener can do to help conserve native species and threatened plants. Private collections of orchids and cycads, for example, are an important gene pool especially for some rare species. Hence, gardeners and plant lovers can play a major part in saving plants.
Indeed, for a few dozen plants, gardens are the last remaining refuge. `Extinct in the Wild', they survive only in cultivation far from their original habitats. Total extinction has been delayed, possibly prevented, by the skills of generations of gardeners. One such example is the popular Cosmos atrosanguineus or Chocolate Cosmos. Last seen in its native Mexican habitat in 1902, it is now found only in gardens and is propagated within the nursery trade only by cuttings.
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