Silicon And Plant Diseases

Silicon, considered to be the second most abundant mineral element in soil, plays an important role in the mineral nutrition of plants. A wide variety of monocot and dicot species have benefited from silicon nutrition, whether direct or indirect, when they are exposed to different types of abiotic and or biotic stresses. Besides the many agronomic and horticultural benefits gained by maintaining adequate levels of this element in the soil and also in the plant tissue, the most notable effect of silicon is the reduction in the intensities of a number of plant diseases caused by biotrophic, hemibiotrophic and necrotrophic plant pathogens in many crops of great economic importance. The aim of this book is to summarize our current understanding of the effects of silicon on plant diseases. The chapters address the dynamics of silicon in soils and plants; the history of silicon in the control of plant diseases; the use of silicon to control soil-borne, seed-borne and foliar diseases in monocots and dicots; the mechanisms involved in the host resistance against infection by plant pathogens mediated by silicon as well as the current knowledge at the omics level, and finally, highlights and prospects for using silicon in the future.

Presenting the first book to focus on the importance of silicon for plant health and soil productivity and on our current understanding of this element as it relates to agriculture. Long considered by plant physiologists as a non-essential element, or plant nutrient, silicon was the center of attention at the first international conference on Silicon in Agriculture, held in Florida in 1999. Ninety scientists, growers, and producers of silicon fertilizer from 19 countries pondered a paradox in plant biology and crop science. They considered the element Si, second only to oxygen in quantity in soils, and absorbed by many plants in amounts roughly equivalent to those of such nutrients as sulfur or magnesium. Some species, including such staples as rice, may contain this element in amounts as great as or even greater than any other inorganic constituent. Compilations of the mineral composition of plants, however, and much of the plant physiological literature largely ignore this element. The participants in Silicon in Agriculture explored that extraordinary discrepancy between the silicon content of plants and that of the plant research enterprise. The participants, all of whom are active in agricultural science, with an emphasis on crop production, presented, and were presented with, a wealth of evidence that silicon plays a multitude of functions in the real world of plant life. Many soils in the humid tropics are low in plant available silicon, and the same condition holds in warm to hot humid areas elsewhere. Field experience, and experimentation even with nutrient solutions, reveals a multitude of functions of silicon in plant life. Resistance to disease is one, toleration of toxic metals such as aluminum, another. Silicon applications often minimize lodging of cereals (leaning over or even becoming prostrate), and often cause leaves to assume orientations more favorable for light interception. For some crops, rice and sugarcane in particular, spectacular yield responses to silicon application have been obtained. More recently, other crop species including orchids, daisies and yucca were reported to respond to silicon accumulation and plant growth/disease control. The culture solutions used for the hydroponic production of high-priced crops such as cucumbers and roses in many areas (The Netherlands for example) routinely included silicon, mainly for disease control. The biochemistry of silicon in plant cell walls, where most of it is located, is coming increasingly under scrutiny; the element may act as a crosslinking element between carbohydrate polymers. There is an increased conviction among scientists that the time is at hand to stop treating silicon as a plant biological nonentity. The element exists, and it matters.

Silicon (Si) plays a significant role in the resistance of plants to multiple stresses including biotic and abiotic stresses. Silicon is also the only element that does not damage plants when accumulated in excess. However, the contribution of Si to plant growth has been largely ignored due to its universal existence in the earth's crust. From numerous intensive studies on Si, initiated in Japan about 80 years ago, Japanese scientists realized that Si was important for the healthy growth of rice and for stability of rice production. In a worldwide first, silicon was recognized as a valuable fertilizer in Japan. The beneficial effects of Si on rice growth in particular, are largely attributable to the characteristics of a silica gel that is accumulated on the epidermal tissues in rice. These effects are expressed most clearly under high-density cultivation systems with heavy applications of nitrogen. Si is therefore recognized now as an ''agronomically essential element'' in Japan. Recently, Si has become globally important because it generates resistance in many plants to diseases and pests, and may contribute to reduced rates of application of pesticides and fungicides. Silicon is also now considered as an environment-friendly element. The achievements of Si research in Japan are introduced in this book, in relation to soils, fertilizers and plant nutrition.

This book mainly presents the current state of knowledge on the use of of Silicon (Si) in agriculture, including plants, soils and fertilizers. At the same time, it discusses the future interdisciplinary research that will be needed to further our knowledge and potential applications of Si in agriculture and in the environmental sciences in general. As the second most abundant element both on the surface of the Earth’s crust and in soils, Si is an agronomically essential or quasi-essential element for improving the yield and quality of crops. Addressing the use of Si in agriculture in both theory and practice, the book is primarily intended for graduate students and researchers in various fields of the agricultural, biological, and environmental sciences, as well as for agronomic and fertilizer industry experts and advisors. Dr. Yongchao Liang is a full professor at the College of Environmental and Resource Sciences of the Zhejiang University, Hangzhou, China. Dr. Miroslav Nikolic is a research professor at the Institute for Multidisciplinary Research of the University of Belgrade, Serbia. Dr. Richard Bélanger is a full professor at the Department of Plant Pathology of the Laval University, Canada and holder of a Canada Research Chair in plant protection. Dr. Haijun Gong is a full professor at College of Horticulture, Northwest A&F University, China. Dr. Alin Song is an associate professor at Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.

The chemistry of plant nutrients in soil. The physiological role of minerals in the plant. Nitrogen and plant disease. Phosphorus and plant disease. Potassium and plant disease. Calcium and plant disease. Magnesium and plant disease. Sulfur and plant disease. Iron and plant disease. Manganese and plant disease. Zinc and plant disease. Copper and plant disease. Chlorine and plant disease. Molybdenum and plant disease. Boron and plant disease. Nickel and plant disease. Silicon and plant disease. Aluminum and plant disease.

Proceedings of the 2nd International Rice Blast Conference, 4-8 August 1998, Montpellier, France

Silicon (Si) is gaining increased attention in the farming sector because of its beneficial effects observed in several crop species, particularly under stress conditions. The magnitude of benefits is predominantly observed in plant species that can accumulate Si above a certain threshold. Therefore, deciphering the molecular mechanisms and genetic factors conferring a plant ability to take up silicon is necessary. Along these lines, several efforts have been made to identify the specific genes regulating Si uptake and distribution in plant tissues. This information finds its usefulness in identifying Si-competent species, and could eventually lead to improving this ability in low-accumulating species. The successful exploitation of Si in agriculture depends highly on the understanding of different Si properties including plant-available Si from the soil, transport within tissues, deposition in planta, and Si effect on different metabolic and physiological processes. In addition, a better comprehension of external factors influencing Si uptake and deposition in plant tissue remains important. A plant can take up Si efficiently only in the form of silicic acid and most soils, despite containing high concentrations of Si, are deficient in plant-available Si. Consequently, soil amendment with fertilizers rich in plant-available Si is now viewed as an affordable option to protect plants from the biotic and abiotic stresses and achieve more sustainable cropping management worldwide. Articles compiled in the present research topic touch upon several aspects of Si properties and functionality in plants. The information will be helpful to further our understanding of the role of Si and contribute to exploit the benefits plants derive from it.