New Phytol. (1997), 137, 563–567

Reviews

Plant Biochemistry. Ed. by P. M. DEY and J. B.

HARBORNE. 18±5¬25±3 cm. Pp. xi­554 with

numerous text-figures. San Diego, CA, USA:

Academic Press, 1997. Price h}b: £49.95,

ISBN 0 12 214674 3.

Plant biochemistry has always been a bit of a Cinderella

science, lagging a dutiful three paces behind its animal

counterpart. As a consequence, most standard textbooks of

biochemistry pay scant regard to plants, including usually

no more than a token chapter on photosynthesis. Never-

theless, plants are our only renewable resource and we

ignore their metabolic capabilities at our peril since,

perhaps by as soon as the middle of the next century, the

chemical industry will have to rely on plants as its major

source of fuel and feedstocks. As pointed out in the final

chapter of this book, even today plants provide as much as

15% of the world’s energy needs. The vast metabolic

diversity of plants also means that they are a potential

source of medicinal compounds, flavourings, colourants

and many other compounds.

The under-representation of plants in standard bio-

chemistry texts has meant that there has always been a

need for specialized textbooks of plant biochemistry and

this volume is the latest product of a distinguished line

dating back to the 1960s. Indeed, a later edition of one of

the early books, Plant Biochemistry by Bonner and Varner,

is cited by the authors of this text as its immediate

progenitor. However, the present volume also owes

something in style to books such as Plant Biochemistry by

Davies, Giovanelli & ap Rees (rather poignantly, the

authors dedicate their volume to Tom ap Rees, who died

tragically last year) and An Introduction to Plant Bio-

chemistry by Goodwin & Mercer. Certainly this book is of

the same genre and equally as valuable for the 1990s and

the beginning of the next century as these earlier texts were

for the 1960s, 1970s and 1980s.

Like Bonner & Varner’s book, this volume is an

accumulation of chapters written by experts in the various

fields of plant biochemistry. It is therefore authoritative.

The editors have themselves written some of the chapters

and also, as they put it, ‘have endeavoured to integrate and

augment, in a meaningful manner, the diverse topics of

plant biochemistry’ included in this book. In my opinion,

they have succeeded admirably. The emphasis of the book

is on plant metabolism, which distinguishes it from some

other recent texts that have covered both the biochemistry

and molecular biology of plants. This book therefore

contains more for plant biochemists than for plant

geneticists, though it does include excellent chapters on

nucleic acids and proteins and on the regulation of gene

expression in plants.

The topics covered commence with an introduction to

the plant, its cell and its molecular components. This is

followed by chapters on photosynthesis, carbohydrate

metabolism (two chapters), lipid metabolism, nitrogen

metabolism, nucleic acids and proteins, and regulation of

gene expression. Secondary plant metabolism is then

represented by chapters on phenolics, isoprenoids and

nitrogen-containing compounds such as non-protein

amino acids, amines and alkaloids. Finally, the book covers

biochemical plant pathology, biochemical plant ecology

and plant cell biotechnology. The coverage is as com-

prehensive as one would expect in a volume of this size and

most chapters are very user-friendly: it was easy to become

immersed in the topic under discussion.

Reviewers always have their favourite chapters which, as

much as anything, reflect their own particular interests.

I particularly enjoyed the chapters on photosynthesis

(Bowyer & Leegood), primary nitrogen metabolism (Lea),

nucleic acids and proteins (Lam) and special nitrogen

metabolism (Wink). They were up to date, interesting and

packed with detailed information. In addition, the last

three chapters, biochemical plant pathology (Walton),

biochemical plant ecology (Harborne) and plant cell

biotechnology (Brownleader & Dey), ensured that the

book finished on a high note. That is not to say, however,

that the other chapters were in any way deficient. To the

contrary, I was impressed by the high standard of all of the

contributions.

It seems rather churlish to raise any criticism about such

an excellent book, but I did have problem judging the level

of knowledge expected of the reader. Some chapters

include some basic biochemistry (for example, general

structures of amino acids, the citric acid cycle) whilst, in

others, concepts such as Michaelis constant and redox

potential remain unexplained. According to the editors,

their book is aimed at students and researchers in plant

sciences. However, among the former, I would expect that

it would appeal mainly to advanced undergraduates taking

specialist courses in plant biochemistry who, like re-

searchers, could reasonably be assumed to have a ground-

ing in basic biochemistry. My inclination, therefore, would

have been to eliminate much of the information that could

have been gleaned from an undergraduate textbook of

biochemistry. On the other hand, I would not have argued

with the editors for deciding otherwise, had I detected a

consistent approach from chapter to chapter.

Despite the above criticism, which I do not rate as

serious, this is an excellent and timely book that should be

in the library of every self-respecting Department of

Biochemistry or Plant Science. It is clearly of value as an

undergraduate text for specialist courses on plant bio-

chemistry and I, for one, will use it as such, though I

suspect that sales to undergraduates will be small. On the

other hand, the book will be indispensable to anyone

conducting research into either plant biochemistry or

molecular biology and, with increasing interest in plants

564 Reviews

and their products, sales should be fairly buoyant. I

certainly hope so.

J. R. G

In Vitro Haploid Production in Higher Plants –

Volume 4: Cereals. By S. MOHAN JAIN, S. K

SOPORY and R. E. VEILLEUX. 24¬16 cm. Pp.

xiv­233 with 40 text-figures. Dordrecht, The

Netherlands: Kluwer Academic Publishers, 1996.

Price h}b: £79.00, ISBN 0 7923 3978 9.

This book deals with haploid production in the most

important cereal species: rice, maize, wheat, barley,

triticale, ryegrass, sorghum, buckwheat, pearl millet, rye

and oat.

Each chapter covers one specific crop, is written by

excellent specialists and contains information on general

aspects of haploid production, the different techniques

that have been used for haploid production: anther culture,

microspore culture and in vitro culture of ovaries}ovules;

the factors that can influence the success, such as genotype

effects, physiological stage of donor plants, microspore

development, pretreatments, culture media and culture

methods. In most chapters, detailed information is pre-

sented on ploidy-level, genetic variation and character-

ization of the regenerants. Breeders will find an excellent

overview of the exploitation and the potential of (doubled)

haploids in the breeding strategy of the mentioned species.

For maize, wheat and barley attention is also paid to

genetic transformation of haploid cells. Economically

important crops such as rice, maize, wheat and barley are

discussed in more detail than the others.

This book gives a comprehensive, up to date and useful

overview of the state-of-the-art knowledge about research

findings, techniques, genetics and use of haploids. It also

gives valuable information for scientists working with

other crops. The book is intended for a broad range of

readers, from specialists in haploid production to advanced

students interested in agricultural biotechnology.

J K

Mycorrhizal Symbiosis. By S. E. SMITH and D. J.

READ. 25¬17 cm. Pp. ix­605 with 172 text-

figures and black­white photographs and 4 colour

plates. London: Academic Press, 1997. Price h}b:

£65.00, ISBN 0 12 652840 3.

The first edition of the book Mycorrhizal Symbiosis by

J. L. Harley and S. E. Smith was published 13 years ago.

Despite the publication of other works containing excellent

contributions covering a wide variety of topics concerning

the mycorrhizal symbiosis, the work of Jack Harley and

Sally Smith has remained the definitive work for students,

university teachers and researchers alike. The book

provided the basic information on each of the different

forms of the mycorrhizal symbiosis ; the biology of the

organisms involved, their structure, development during

colonization, their role in mineral nutrition and their

effects on the carbon economy of plants, and also served as

a detailed and extensive review of the literature up to that

date. The book, however, served another more important

role by integrating in a set of essays information on

translocation, transfer of metabolites, specificity and

ecological aspects from each form of the mycorrhizal

symbiosis. In this way, the book provided a current state

of knowledge on these topics whilst, more importantly,

outlining questions and future research directions which

indeed became a focus of research in many groups during

the following 13 years. Not surprisingly, the authors of the

second edition of this work express their trepidation at

emulating the achievements that were made with that first

edition.

The mycorrhizal symbiosis which is formed between

plant roots and fungi occurs in most plant species and in

almost all the terrestrial ecosystems in the world. The first

edition of this book emphasized that because of both its

abundance and its beneficial role in the mineral nutrition

of plants the mycorrhizal symbiosis plays a significant role

in the functioning of natural ecosystems and that its

potential use in agriculture, forestry and polluted environ-

ments is considerable. The mycorrhizal symbiosis is

clearly of interest to many plant and fungal biologists

working in the fields of ecology, physiology, plant–fungal

molecular interactions, plant nutrition, agriculture, for-

estry and the environment. One other legacy of that first

edition is, therefore, that there has been an explosion in the

amount of research and the number of publications on the

mycorrhizal symbiosis in the past 13 years making the

authors’ task more daunting.

The format of the book has remained similar to the first

edition. The first four sections cover the main mycorrhizal

types; vesicular–arbuscular (VA) mycorrhizas, ectomy-

corrhizas, mycorrhizas in the Ericales and orchid mycor-

rhizas. The fifth section again takes an integrated approach

to look at four particular topics concerning this symbiosis.

There are two general chapters on uptake, translocation

and transfer of nutrients and the role of mycorrhizas in

ecosystems. The final two chapters cover the effects and

the uses of the vesicular–arbuscular symbiosis in agricul-

ture and horticulture and mycorrhizas in other managed

environments: forest production and in polluted environ-

ments.

In the last 13 years there have actually been very few

individual studies that have led to significant or major

advances in our understanding of the mycorrhizal sym-

biosis. Yet despite this, the authors have comprehensively

brought together the wealth of research that has been

carried out in this field and the feeling from reading the

chapters is that clearly the field of mycorrhizal research, as

a whole, has significantly advanced during this period and

is doing so at a rapid rate. The first section on VA

mycorrhizas includes much new information on the

taxonomy, phylogeny and evolution of the symbiosis,

covering the recent advances in this field afforded by the

use of molecular techniques. The chapter on the genetic,

cellular and molecular interactions in the establishment of

VA mycorrhizas is completely new and demonstrates the

exciting advances taking place in this field. The chapters

dealing with the ectomycorrhizal symbiosis are equally

exciting especially in their treatment of the molecular and

biochemical events taking palace in the development of the

symbiosis. The chapters on the ericoid, arbutoid and

orchid mycorrhizas are no less interesting but highlight the

Reviews 565

disparity between the small amount of research going on in

these areas compared with that on the VA and ectomy-

corrhizal symbioses. Of the general themes, I found that

chapters on uptake, translocation and nutrient transfer and

the role of mycorrhizas in ecosystems to be well written,

substantial in content and informative. The approach

taken by the authors in the chapter concerning the

ecological role of mycorrhizas has been to treat separately

their role in each of the major biomes of the world. At first

glance, this approach gives the impression of a rather old-

fashioned descriptive approach to the subject, which is

often not favoured in modern ecology. I was pleasantly

surprised to find within each of these subsections that the

authors had brought together the research from both

descriptive and experimental ecological investigations,

giving a balance between the role of mycorrhizas in

ecosystem ecology and functioning and the more subtle

effects that mycorrhizas might have on the processes

determining plant diversity, co-existence between plants,

plant population biology and community structure. My

only concern about this approach is that there is no reason

to believe that some of the processes described for one

biome may not also be affected by mycorrhizas in the same

way in another biome, but this is a minor point. The final

chapter on mycorrhizas in managed environments covers a

variety of topics which could be important for future

applications of mycorrhizal research.

Each chapter is written in a detailed and informative

way, covering an enormous amount of recent literature.

The authors have given in places some quite personal

interpretations of some of the experimental work cited,

especially on certain controversial topics. As a reader this

gave me some added enjoyment in reading some of the

chapters. I was, however, already familiar with these

controversies and I hope that it will be clear to a reader

who is new to the subject that these are personal

interpretations of controversial issues. What I found made

the text particularly interesting and helpful was that the

authors do much more than just reviewing the literature

but provide clear indications of which areas require urgent

experimental investigation and they have, therefore, set

some challenges and future research directions for mycor-

rhizal researchers. In each chapter, almost all the figures

are new and have been carefully chosen to visually enhance

important points that are made in the text. The collection

of photographic reproductions in the book is superb in

quality and detail, and where photographs from the first

edition have been used again they have often been

supplemented with additional photographs from later

publications.

This book is clearly essential reading for anyone starting

research on the mycorrhizal symbiosis and as a reference

for researchers who have already been working in this field

for some time. As a measure of its popularity I have to say

that I had great difficulty in actually holding on to the book

long enough to read it throughout, because so many of my

colleagues also wanted to read and refer to its various

chapters. All in all, I can recommend this book as a

standard reference work and as interesting reading.

However, I expect that some of the most exciting results in

mycorrhizal research, particularly concerning the mol-

ecular interactions and signals between plants and the

fungi are likely to be produced over the next few years and,

therefore, I hope that the authors will not wait for another

13 years to elapse before writing a third edition.

I R. S

Principles and Practice of Managing Soilborne Plant

Pathogens. Ed. by R. HALL. 23¬15 cm. Pp.

xiv­330 with 21 text-figures. St Paul, MN, USA:

APS Press, 1996. Price h}b: US$49.

This is the seventh in a series of books on soilborne plant

pathogens which began in 1965. The volumes have largely

been associated with the International Congresses of Plant

Pathology and can be regarded as ‘advances’ type volumes

giving state-of-the-art reviews. I still find myself making

frequent reference to the first volume held in 1963 in

Berkeley, California. All volumes have been useful. It is a

little frustrating that the ‘series ’ with its various publishers

and formats is not listed in the present volume and even

the date of the first volume is wrong in the first line of the

introduction. This however, should not detract from the

13 excellent chapters from the Congress held in Montreal

in 1993. It concludes with an epilogue by the editor.

The prologue chapter by Hornby is an excellent

overview of the field, covering a wide spectrum from

precision farming to molecular biology, and strays into the

world of politics and the Common Agricultural Policy. As

always the author is provocative and very perceptive.

The next section, on ‘Fundamentals ’, containing five

chapters is led off by Campbell and Neher on root disease

epidemiology and management. This is potentially one of

the most exciting areas of plant pathology, but in reality

this quantitative area of plant pathology, with a few

notable exceptions (e.g. Gilligan), has not kept up with the

excitements in entomology and human disease epidemi-

ology.

Baker was always a stimulating thinker in the approach

to biological control of soilborne pathogens and it is great

to have his chapter with Paulitz before his untimely death

in 1994. Unfortunately the number of commercial exploit-

ations has been frankly disappointing. There have only

been a few groups that have made major contributions to

the molecular biology of antibiosis and biological disease

control in the rhizosphere. Thomashow and Weller report

their own studies in relation to the other groups and this is

an excellent, succinct summary. Detection of pathogens

and antagonists is crucial to this area of study and this is

outlined by Van Vuurde and Postma. This is an area of

rapid advance today and unfortunately the chapter is

already a little out of date. The section is completed with

a chapter by Trudgill on the unusual thermal time basis of

pest epidemiology and ecology.

The second main section of the book covers cases. Most

of them have been well discussed elsewhere but it is very

useful to have updates. These are management of plant

parasitic nematodes (Kerry & Evans), crown gall (Moore

& Canfield), fusarium wilts (Alabouvette et al.), Tricho-

derma harzianum as antagonists (Tronsmo), organic

matter, species diversity and disease severity (Hoitink et

al.), soil solarization (Katan), and fusarium root rot of bean

(Hall). Interestingly, the chapters on crown gall and

Trichoderma, areas where there have been many advances,

do not indicate how molecular biology is contributing to

566 Reviews

understanding mechanisms of biocontrol, or the potential

of genetic manipulation in disease control.

Concluding with the epilogue by the editor on theory

and practice in managing soilborne plant pathogens, some

interesting tactics are presented. However, in my opinion

the failing is in not adequately recognizing interdisci-

plinary approaches to this complex subject, which is

dominantly studied by phytopathologists. Even soil micro-

biologists, let alone plant physiologists, physicists and

chemists, have limited representation. Mixed represen-

tation is vital for progress. Another criticism is that three

years for publication after the meeting is far too long,

perhaps confirming the lack of urgency that seems to

surround the subject at present. One is left with feeling

that a new ‘puff of life’ is necessary to rejuvenate the

subject in times when research money is more accountable

and difficult to obtain. Nonetheless I am delighted to have

this book on my shelf and I expect many others to acquire

it as a useful addition to the series.

J. M. L

Turfgrass Diseases: Diagnosis and Management. By

G. L. SCHUMANN and J. D. MDONALD.

Interactive CD-ROM with over 350 images. St

Paul, MN, USA: APS Press, 1996. Single user

(outside USA) price: US $310, ISBN 0 89054

219 8.

This interactive guide was viewed using the Windows 952operating system on a Pentium2}133 MHz PC with 32 MB

of RAM and an SVGA (minimum system requirements

are Windows 3.12, 486}25 MHz, 8 MB and VGA). Set up

was quick and easy, although some font and screen size

adjustments were necessary.

The guide is for commercial turf-grass managers,

scientists and students interested in fungal diseases and

other diseases or disorders of turf and in readily available

advice on how to manage these. With a plethora of menu-

driven facilities, all of which will be second nature to the

computer-literate, goals may be reached from different

starting-points, such as knowing the host, or following up

specific symptoms. There is an image browser and there

are guides to turf identification, pathogens and turf grass

taxonomy. A glossary deals with most, but not all, of the

technical terms encountered. Much additional informa-

tion, as diverse as illustrated disease cycles and reference

lists, is available at appropriate places.

The CD-ROM contains much of the material (verbatim

to the extent of at least one typographical error; ‘hetero-

tallic ’ under bermudagrass decline) from the updated 2nd

edition of the book, Compendium of Turfgrass Diseases by

R. W. Smiley, P. H. Dernoeden & B. B. Clarke, APS,

1992. This book is already proven: the first edition,

published in 1983, sold over 18000 copies. The CD-ROM

contains additional material, which improves the inter-

active and diagnostic nature of the guide. Depth and detail

of the information on diseases and their causes tend to

remain at the ‘compendium’ level. The CD-ROM has

more coloured images than the book, including many

which can be magnified, and are therefore clearer to see

than those reproduced in the book. Line drawings,

however, lack the clarity of those in the book.

There is no doubt that this guide succeeds as a ‘simple

yet authoritative diagnostic tool ’, although its value for

users outside the USA may be lessened slightly by a US

bias. Patch disease distribution maps, for instance, are for

the USA only. Traditional bibliophiles may not be

convinced that the additional material and facilities of the

CD-ROM are worth the extra US $166, or so, over the

price of the Compendium of Turfgrass Diseases.

D H

Seaweed Ecology and Physiology. By C. S. LOBBAN

and P. J. HARRISON. 25±5¬17±5 cm. Pp.

xi­366 with 194 text-figures. Cambridge: Cam-

bridge University Press, 1994 (h}b) 1997 (p}b).

Price h}b: £50.00, ISBN 0 521 40334 0; p}b:

£22.95, ISBN 0 521 40897 0.

This textbook was derived, by being ‘thoroughly reworked

and rewritten’ (authors’ preface, p. xi), from The Physio-

logical Ecology of Seaweeds (1985) by the authors and Mary

Jo Duncan. This revision has involved, inter alia, a change

in the order of chapters, an encapsulation of algal

structures and life histories, more detail on mariculture

and algal biotechnology, increased use of tropical and

austral examples, the incorporation of personal perspec-

tives of two–three pages each by seven phycologists on

community-level topics, and a volunteered taxonomic

appendix by Paul Silva and Dick Moe.

The topics covered in each chapter are, in order of

appearance, Morphology, life histories and morphogen-

esis, (68 pp.), Seaweed communities (30 pp.), Biotic inter-

actions (24 pp.), Light and photosynthesis (40 pp.),

Nutrients (47 pp.), Temperature and salinity (31 pp.),

Water motion (14 pp.), Pollution (28 pp.), and Seaweed

mariculture (17 pp.). The taxonomic appendix occupies

seven pages, the references 51 pages, and the Index eight

pages. The six personal perspectives all occur in Chapter

2, and are by Trevor A. Norton (The rocky intertidal

zone), Mark M. Littler and Diane S. Littler (Tropical

reefs as complex habitats for diverse macroalgae), Paul K.

Dayton (Kelp forests), Piet H. Nienhaus (Seaweeds in

estuaries and salt marshes), Marilyn M. Harlin (Seagrass

beds as habitats for algae), and Robert T. Wilce (The

Arctic subtidal as a habitat for macrophytes).

Overall, I rate this as an excellent book. It is written in

a clear style, and is illustrated with many figures and

tables, and some half-tone prints. The coverage is

comprehensive, as might be expected with 51 pages of

references in a book of 366 pages. The stated policy of the

authors on literature citations was ‘to select papers that

help put together a coherent (if reticulate!) story’. This

approach could result (in the wrong hands) in simplistic,

or biased, conclusions; this has been avoided in this

volume, at least to the extent that this is possible within the

space confines of a book of this length. The level is

appropriate for advanced undergraduates and post-

graduates, the stated target audience for the book.

The changes from the earlier volume have all been to the

good; in particular, I applaud the placing and content of

the first two chapters, which set the structural, life history

and community ecology background to the more physio-

Reviews 567

logical and applied (pollution and mariculture) aspects

covered later. The taxonomic appendix is very useful in

putting the organisms mentioned in the text into the

context of classical taxonomy; this is rather conservative

(but none the worse for that), e.g. assigning all green algae

sensu stricto to the Class Chlorophyceae, although in

Chapter 1 mention is made of virtually all green seaweeds

belonging to the Class Ulvophyceae. It is helpful that the

taxonomic appendix gives authorities for species. The

reference list gives titles for 1800-odd citations, and also

indicates the section of the text in which a particular

reference is cited. The index is helpful, and is quite

comprehensive, e.g. over half of the algal genera in the

taxonomic appendix are mentioned in the index.

Despite the usually lucid phraseology there are some

places in which the meaning is not clear. Thus, on p. 1 we

find that ‘only a few diverse angiosperms (the seagrasses)

occur in marine habitats (although the latter are scarcely

known)’, while on p. 156 we read that ‘ the underlying

cause (of noon and afternoon photosynthetic rate depression

in situ) is not known, but it could be saturation of Calvin-

cycle intermediates’.

In addition to these infelicities of expression, there are a

few inaccuracies. Thus (p. 60) not all Durvillaea species

have intercellular gas spaces (they are absent from D.

potatorum mentioned on p. 305), and (p. 88) Halimeda

does not, strictly speaking, have leaf area. On p. 128 it is

surely up to the authors whether they choose 280–315 nm

or the 280–320 nm range which is also used to define u.v.-

B, while on p. 144 CO#

(sometimes HCO$

−) is fixed onto

phosphoenolpyruvate, not pyruvate. The photosynthetic}respiratory equation on p. 153 would be better with 12

H#O on the left-hand side and 6 H

#O on the right-hand

side, while (regardless of how Raven & Beardall (1981) is

interpreted), the Mehler reaction per se in the presence of

high superoxide dismutase and ascorbate peroxidase

activities takes up as much O#as is released in photosystem

two, while more O#

is taken up than photosystem two

releases if intermediates in the complete reduction of O#to

H#O (i.e. O

#

− and H#O

#) accumulate. In the consideration

of essential elements (pp. 164, 165), there is no mention of

the ubiquitous cytochrome oxidase under Cu, or of ‘Zn

fingers’ (pp. 164, 195) under Zn, although protein

synthesis is mentioned on p. 195. The definition of active

transport on p. 172 is not rigidly adhered to (e.g. for

uptake of Zn and Co on p. 194 in relation to elec-

trochemical gradients, and on p. 178, in terms of the

frailty of saturation kinetics, for NH%

+). On p. 190 it would

have been helpful to have emphasized the role of

uninhibited nuclear and crystal growth in CaCO$

pre-

cipitation. On p. 195 it is not made clear why SO%

#−

competitive inhibition of MoO%

#− uptake should increase

the energy cost of Mo uptake; is it an increased quantity of

transporter for MoO%

#− the intended extra energy cost?

Finally, on p. 262, the binding of Cd#+, Pb#+ and Sr#+ to

extracellular polyanions should be considered quanti-

tatively in the context of the more abundant Ca#+ and,

especially, Mg#+ in seawater. However, the overall stan-

dard of scientific precision is high. There are also very few

typographical errors (e.g. Pelvitia (for Pelvetia) on p. 237,

and Anabaina (for Anabaena) on p. 301).

These few infelicities, scientific inaccuracies and omis-

sions, and typographical errors do not detract from my

overall impression that this book provides as compre-

hensive and lucid an advanced undergraduate}post-

graduate text in its subject area as can be fitted into 316

pages. While it seemed rather odd to this reviewer to be

considering this paperback (published in 1997), which is

internally identical to the hardback published in 1994 (and

for which excerpts from reviews are printed on the back of

the paperback!) and thus is rather dated as far as references

are concerned, I recommend it to any serious student of

seaweed ecology and physiology; it is good value for

money.

J. A. R