Plant Mineral Nutrients. Methods and Protocols. Frans J.M. Maathuis (editor). 2013. Humana Press, Springer, New York. 297 pages. $119.00 Hardcover. ISBN 978-1-62703-151-6.

This book contains a collection of procedures that are used in research in plant mineral nutrition. It covers topics of plant growth parameters, composition, and elemental analyses of plants and soils. A list of references is provided at the end of each chapter. The chapters are written by plant and soil scientists from around the world and include the editor. The text covers step-by-step procedures for 1) culture of whole plants and cell suspensions, 2) culture of symbiotic organisms with plants, 3) measurements of plant composition by instrumental analysis, sampling, and analysis of xylem and phloem fluids, single cells, and cytosols, and 4) studies of genetics and phenotyping of ion accumulation and nutrient-use efficiency. Each procedure presents detailed lists of materials needed and methods for steps within the procedure. If outside help is needed for instrumentation or skills that are not commonly available in research laboratories, instructions are given for how to access public or private facilities with specialized capabilities.

The first five chapters cover growing of whole plants, organs of plants, or cultures of cells. The first chapter addresses roles and function of the 14 mineral plant nutrients. Information about each nutrient is brief and addresses the forms of nutrients used by plants, nutrient uptake and transport, and assimilation and biological functions of each nutrient. Chapter 2 provides guides for growing arabidopsis, barley, and rice, which are used frequently in research. The guides cover growing of the plants in soil, hydroponics, and in vitro. The third and fourth chapters address protocols for growing mycorrhizae and rhizobia in symbiosis with plants. Culture of plant cell suspensions and isolation of protoplasts from these cultures are covered in Chapter 5.

The next several chapters cover analyses of soils, plant tissues, single cells, and flux of elements in xylem and phloem. Chapter 6 describes analysis of clay mineral and organic matter of soils by visible-near infrared reflectance spectroscopy. Chapter 7 deals with simultaneous measurements of nitrate, sulfate, phosphate, and other anions in plant tissue by high performance liquid chromatography. Chapter 8 covers analyses of multiple chemical elements in plant tissues by inductively coupled plasma spectrometry (ICP). Methods of digestion and procedures to employ ICP technologies in elemental determinations are presented. Chapter 9 describes use of X-ray fluorescence procedures to examine in situ distribution of elements in plants. The technology can be employed to give two-dimensional or three-dimensional imaging of elemental distribution in plants. Use of this technology requires specialized synchrotron facilities available only at a limited number of laboratories in the world. Flux measurement with radioactive tracers is the subject of Chapter 10. Cation flux is emphasized with potassium as a model. A noninvasive technique for measuring ion flux in plants using instrumentation called microelectrode ion flux estimation is covered in Chapter 11. Use of this technique is limited to about 20 laboratories in the world, but has the advantage of allowing researchers to study kinetics of ion flux into and from plant tissues, such as along root zones, under essentially natural conditions for periods as short as 5 seconds or for days. The technique has been applied to assess nutritional deficiencies and toxicities in plant tissue and responses to abiotic stresses.

Sampling and analysis of phloem and xylem sap are presented in Chapters 12 and 13. Procedures for collecting phloem sap from spontaneous exudation, chelator (EDTA)-facilitated exudation, and insect (aphid) stylectomy are described and evaluated. Collection of xylem sap involves collection of exudate from root pressure, application of pressure to roots or stems, and vacuum pumps. Chapter 14 on sampling of single cells describes and evaluates methods for determination of solute concentrations in individual cells and tissues. These procedures include cell-sap extraction with pressure-driven devices and determination of the contents by various processes of examination and instrumental analyses that detect organic and inorganic constituents. Chapter 15 also addresses cellular analyses but deals with cytosolic concentrations in live cells, rather than in extracts, and utilizes various dyes. The emphasis is on determination of sodium. Examination of tissues involves microscopy or fluorescence spectroscopy. Use of ion-selective microelectrodes to measure intracellular ionic concentrations is covered in Chapter 16. In this procedure, a micropipette is pulled into a fine tip to form the microelectrode that can be inserted into a cell. Electrical potential against a standard electrode can be used to measure membrane potentials, ionic concentrations in cells, or ionic gradients across membranes.

Large-scale and phenotypic profiling of arabidopsis to gain insight into mineral nutrient accumulation in plants is discussed in Chapter 17. This approach is used to identify genes that control variation in the accumulation of chemical elements in a natural environment and involves examinations of thousands of samples. Chapter 18 examines plant phenotyping to study nutrient-use efficiency through application of remote sensing and spectral reflectance measurements. The model presented is a greenhouse situation and employs digital color photographs to measure plant size and leaf color in response to different nutrient supplies.

This book has a collection of methods, most of which are used commonly in research in plant nutrition. The methods are easy-to-follow protocols that researchers can use readily in their laboratories or are methods that are employed by public or private laboratories with special facilities to assist researchers. The methods in this book can be used directly as presented or with modifications and would be a valuable reference for researchers in studies of plant nutrition. The book will be of value to researchers to document the methodology that they employ. Many researchers cite an instrument as a procedure or sometimes refer to a manual to document a procedure. These kinds of references do not inform other researchers of the methodology involved and may not allow for the other workers to repeat the research or to evaluate the methodology used in a report. The book will allow for investigators to learn about procedures with which they are not experienced and will permit experienced workers to improve their proficiency in plant analysis.