Vesicular-arbuscular mycorrhizal fungi can affect the water balance of both amply watered and droughted host plants. This review summarizes these effects and possible causal mechanisms. Also discussed are host drought resistance and the influence of soil drying on the fungi.

Water relations, drought and vesicular-arbuscular mycorrhizal symbiosis

Preface.- Contributors.- List of Abbreviations.- Section 1: Basic Principles: Introduction.-Sources of Heavy Metals and Metalloids in Soils.- Chemistry of Heavy Metals and Metalloids in Soils.- Methods for the Determination of Heavy Metals and Metalloids in Soils.- Effects of Heavy Metals and Metalloids on Soil Organisms.- Soil-Plant Relationships of Heavy Metals and Metalloids.- Heavy Metals and Metalloids as Micronutrients for Plants and Animals.-Critical Loads of Heavy Metals for Soils.- Section 2: Key Heavy Metals And Metalloids: Arsenic.- Cadmium.- Chromium and Nickel.- Cobalt and Manganese.- Copper.-Lead.- Mercury.- Selenium.- Zinc.- Section 3: Other Heavy Metals And Metalloids Of Potential Environmental Significance: Antimony.- Barium.- Gold.- Molybdenum.- Silver.- Thallium.- Tin.- Tungsten.- Uranium.- Vanadium.- Glossary of Specialized Terms.- Index.

Heavy metals in soils : trace metals and metalloids in soils and their bioavailability

http://utsc.utoronto.ca/%7Ebritto/publications/amtox.pdf

NH4+ toxicity in higher plants: a critical review

The rhizosphere is a complex environment where roots interact with physical, chemical and biological properties of soil. Structural and functional characteristics of roots contribute to rhizosphere processes and both have significant influence on the capacity of roots to acquire nutrients. Roots also interact extensively with soil microorganisms which further impact on plant nutrition either directly, by influencing nutrient availability and uptake, or indirectly through plant (root) growth promotion. In this paper, features of the rhizosphere that are important for nutrient acquisition from soil are reviewed, with specific emphasis on the characteristics of roots that influence the availability and uptake of phosphorus and nitrogen. The interaction of roots with soil microorganisms, in particular with mycorrhizal fungi and non-symbiotic plant growth promoting rhizobacteria, is also considered in relation to nutrient availability and through the mechanisms that are associated with plant growth promotion.

Acquisition of phosphorus and nitrogen in the rhizosphere and plant growth promotion by microorganisms

Stabilization of As, Cr, Cu, Pb and Zn in soil using amendments – A review

Arbuscular mycorrhizal fungi (AMF) benefit plants by allowing them to grow and produce in relatively harsh mineral stress environments. This has been attributed extensively to ability of AMF to expand the volume of soil for which mineral nutrients are made available to plants compared to what roots themselves would contact. This article reviews the effects of AMF on enhancing/reducing acquisition of phosphorus (P), nitrogen (N), sulfur (S), boron (B), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), aluminum (Al), silicon (Si), and some trace elements in plants. The nutrients enhanced most in host plants grown in many soils (e.g., high and low soil pH) are P, N, Zn, and Cu, but K, Ca, and Mg are enhanced when plants are grown in acidic soils. Many AMF have also the ability to ameliorate Al and Mn toxicities for plants are grown in acidic soil.

Mineral acquisition by arbuscular mycorrhizal plants

Plant genotypes differ in their uptake, translocation, accumulation, and use of mineral elements. Examples of genotype differences to iron, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, boron, copper, zinc, and molybdenum are discussed. Current knowledge is sufficient to indicate that many crop plants can be improved for the efficient use of mineral elements and better adaptation to mineral stress conditions.

Plant genotype differences in the uptake, translocation, accumulation, and use of mineral elements required for plant growth

Growth and P, K, Ca, Mg, Mn, Zn, Fe, and Cu concentrations and contents were determined in Al-tolerant and Al-intolerant corn (Zea mays L.) inbreds when grown at various levels of Al. B57 was more tolerant to Al than was Oh40B. Relatively low Al levels (up to 5 mg/l) enhanced B57 growth but inhibited Oh40B growth. With few exceptions, Oh40B root and leaf concentrations of the elements decreased with added Al. The decreases in element concentrations were not as large for B57 as they were for Oh40B. The Mg concentrations and contents decreased more than the other elements in all inbreds with added Al. Root Mg decreased more than leaf Mg. Total uptake of some elements were higher at low Al than with no Al. Inasmuch as Mg has a pronounced effect on root growth, low Mg may be an important response in plants sensitive to Al.

Effect of aluminum on growth and mineral elements of al-tolerant and Al-intolerant corn

The growth of plants in nutrient solutions is an invaluable tool for mineral nutrition studies. Successful growth of plants in nutrient solutions require special attention and consideration. Details and helpful ideas for the growth of plants in nutrient solutions are often omitted in publications where techniques like these are used. The objective of this report is to focus on some of the concerns, successes, experiences, and problems noted for the growth of sorghum and corn in nutrient solutions. Topics discussed are nutrient solution composition, pH of nutrient solutions, phosphorus concentrations, sources of Fe in solutions, plus several suggestions and comments for successful growth of sorghum and corn in nutrient solutions.

Nutrient solution growth of sorghum and corn in mineral nutrition studies

Plants colonized with arbuscular mycorrhizal (AM) fungi generally have greater growth and acquisition of mineral nutrients, and often have greater ability to withstand drought compared to nonmycorrhizal (nonAM) plants. This study determined effects of water stress (WS) versus no WS (nonWS) and the AM fungus Glomus monosporum (AM vs nonAM) on growth, acquisition of phosphorus (P), zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe), and water use in two durum wheat (Triticum durum Desf.) cultivars exhibiting differences in resistance to WS. Plants were grown on soil [low P silty clay (Typic Xerochrept, pH=8.1)] and sand mixtures in a greenhouse. Shoot and root dry matter (DM), total root length (RL), and root colonization with AM for plants grown under non WS were higher than for plants grown under WS. Much of the reduction in DM was overcome by AM plants grown under WS. The ‘drought‐resistant’ wheat cultivar CR057 had higher AM root colonization than the ‘drought‐sensitive’ cultivar CR006 when ...

R. B. Clark

Papers

Mineral acquisition by arbuscular mycorrhizal plants

Plant genotype differences in the uptake, translocation, accumulation, and use of mineral elements required for plant growth

Effect of aluminum on growth and mineral elements of al-tolerant and Al-intolerant corn

Nutrient solution growth of sorghum and corn in mineral nutrition studies

Growth, mineral acquisition, and water use by mycorrhizal wheat grown under water stress