T.H. Thomas

Responses of sugar beet (Beta vulgaris L.) to drought and nutrient deficiency stress

The responses of two sugar beet genotypes, 24367 (putative droughttolerant) and N6 (putative drought intolerant), to drought and nutrientdeficiency stress were investigated in an attempt to identify reliable andsensitive indicators of stress tolerance. In glasshouse-grown plants of bothgenotypes, relative water content (RWC) of the leaves decreased and leaftemperature increased in response to drought stress. Genotype differences inresponse to drought included leaf RWC, glycine betaine accumulation, alterationof shoot/root ratio and production of fibrous roots. Thus, in comparison to N6,genotype 24367 lost less water from leaves, produced more fibrous roots,produced more glycine betaine in shoots and tap roots and had a much reducedshoot/root ratio in response to withholding water for up to 215 h.The hydraulic conductance and sap flow of sugar beet seedlings grown innutrientculture decreased when subjected to nitrogen deficiency stress. Under nitrogensufficient conditions sap flow was greater in 24367 than in N6. The resultsindicate that genotype 24367 is more tolerant to stresses induced by water andnitrogen deficiency and that increased fibrous root development may be a majorfactor in increasing sap flow via a concomitant enhancement of aquaporinactivity.

Crop production science in horticulture series.

prediction from sequence, which is the topic of this volume. However, although it is generally considered that all of the information required for protein folding is encoded within the primary structure, deciphering this has proved to be far from simple. Consequently, this volume contains a higher proportion of theory and discussion and fewer practical methods than most of its sister volumes. The eighteen chapters build up an account of protein structure prediction from its basic principles, starting with the analysis of the primary structure by alignment with related sequences and the recognition of conserved patterns and of protein domains. This is followed by an excellent, concise discussion of secondary structure prediction, which leads into the development and application of more sophisticated methods to predict folding (including the formation of specific motifs such as loops and folds and homology modelling), membrane protein structure, active sites, and the docking of proteins with other proteins and with peptide ligands. Much of the work described is still undergoing development and is certainly not suitable for routine application by non-experts. However, there is no doubt about the potential importance of protein structure prediction for “post-genomic” studies and this volume provides an excellent account of the current status.

The promotive effect of combustion products from plant vegetation on the release of seeds from dormancy

In darkness, dormancy was imposed on seeds of lettuce (Lactuca sativa L. cv. Grand rapids) by high temperature and on seeds of oilseed rape (Brassica napus L. cv. Apex) by osmotic stress using polyethylene glycol (PEG 8000). In both cases, dormancy was broken by incubating the seeds in aqueous extracts of combustion products from Salix viminalis wood chips or Themeda triandra leaves. Dormancy of rapeseed, but not lettuce, was also broken by a solution of smoke from burnt straw of Triticum aestivum. The greatest stimulation from burnt vegetation was achieved with an aqueous extract of pyrolysed willow wood chips, which had been subjected to temperatures of up to 800 °C during combustion in a down-draught gasifier. This suggests that some biologically active substances obtained from combustion of plant tissues are highly heat-stable.

Identification of a sucrose nonfermenting-1-related protein kinase in sugar beet (Beta vulgaris L.)

A 154 bp polymerase chain reaction product, SBKIN154, showing 76–83% sequence identity with sucrose nonfermenting-1 (SNF1)-related protein kinase nucleotide sequences from other plant species was amplified from sugar beet storage root RNA. Southern blot analysis using SBKIN154 as a hybridisation probe suggested that sugar beet contains either a single-copy SNF1-related gene or a small gene family of highly conserved genes. An antibody raised to a heterologously-expressed fusion of the rye SNF1-related protein kinase, RKIN1, and maltose binding protein, recognised a protein of the expected size (Mr approx. 60,000) on western blots of storage root, stalk, leaf and root extracts. Measurements of SNF1-related activity were made using a specific peptide (SAMS) phosphorylation assay. Activity was highest (0.38 nmol min-1 mg-1 protein) in developing storage roots and lowest (0.035 nmol min-1 mg-1) in fibrous roots.

Is there a circadian germination response to red light in celery (Apium graveolens L.) seeds

Celery seeds are dormant when incubated at high temperatures in theabsence of light. This dormancy is broken by exposure to short durations of redlight or by treatment with a mixture of gibberellin and cytokinin. InBrydons Prize White, a medium-dormant cultivar, a 5 minexposure to red light after 24 h imbibition in the dark at22 °C caused 21% of seeds to germinate. BA(10−5 M) enhanced this red light effect. When a 5min red light break was given at different times during the secondday of imbibition, a circadian response in germination percentage was observed.This rhythmic response was detected in further experiments carried out over 5days, the cycles being of ca. 22 h duration. This circadianresponse appears to be established during seed development and is triggered bythe process of water imbibition, since altering the time of imbibition did notshift the response peak. The addition of N6-benzyladenine to theincubation medium did not remove the circadian response but improved thegermination values overall.

Studies on allometric growth relationships of sugar beet(Beta vulgaris) grown in nutrient culture

The effects of genotype and seed size on the growth of sugar beetseedlings in liquid nutrient culture medium were examined. Seed size waspositively correlated to seedling weight at the 5/7-leaf stage of developmentbut had little influence on mean total root to shoot ratio. At the 8-leaf-stagethere was considerable variation in the fibrous root to shoot ratios betweenindividuals in each of three cultivars. Nevertheless, the mean root to shootratio of seedlings of each cultivar was relatively similar. However, largegenotypic differences were detected in the depletion of specific elements fromthe nutrient culture solution, this being particularly so for nitrogen,potassium and sodium.

Lupins as crop plants: Biology, production and utilization. Edited by J. S. Gladstones, C. Atkins and J. Hamblin. 1998.

This book, first published in 1966, continues to be a standard text for students and practitioners of tropical agriculture. The third edition has been fully updated throughout and includes new chapters on forestry and tropical climates. Subjects covered in the 18 chapters include: tropical soils, soil and water conservation, land clearing, drainage and weed control, rainfed arable farming systems, rice-based farming systems, agroforestry, plantation crops and the improvement of tropical crops. Livestock production in the tropics is addressed in eight chapters covering: the production of animal feed, livestock improvement through feeding, nutrition, health, hygiene and breeding, classes of livestock and cattle management. The chapters are written by 12 authors, all eminent in their fields, including of Prof P N Wilson who wrote all the chapters on livestock. Tables, graphs, black and white photographs, a good index and about 1,200 references amply supply the text. It is not a cheap book but it is certainly excellent value. For another generation, Webster and Wilson will be one of the first points of reference on agriculture in the tropics.

Practical Applications of Plant Molecular Biology. Edited by R. J. Henry

This is primarily a student textbook but it also provides a useful source of reference for those involved in agriculture, plant breeding, crop protection, crop improvement, biotechnology and molecular biology. It covers the main areas of plant molecular biology clearly and concisely, without becoming too convoluted or involved, which is often a criticism of some texts dealing with this subject. Thus, the book covers the identification of plants and their pathogens using molecular techniques, the estimation of genetic variation in plants, molecular markers for plant improvement and the use of plant transformation techniques for the improvement of quality and introduction of resistance. In chapter 1, the main molecular techniques are described briefly and the information is well supported by a series of clear diagrams and plates. Chapter 2 should be of particular interest to those involved in biodiversity and the protection of genetic resources whilst the third chapter contains the basic information pertaining to molecular marker techniques and their application to plant breeding and selection. Chapter 4 provides examples of the application of plant transformation technology to produce transgenics with commercially desirable characteristics such as herbicide resistance, improved quality, resistance to pests and diseases, stress resistance and antigen production; intellectual property issues and regulations pertaining to transgenic plants are also covered. Useful routine protocols in plant molecular biology are described briefly but clearly in the final chapter. There are seven appendices containing miscellaneous information which will be of interest to those involved in the many aspects of molecular biology. Each chapter ends with a list of references and several pertinent questions for the student. This is a nice paperback at a competitive price, particularly useful as a guide and reference text for the enquiring student.

Oilseed crops. Edited by E. A. Weiss

This is the second edition of Oilseed Crops, which has been completely rewritten to include the latest agricultural research, the influence of biotechnology on crop production and processing, and advances in farm machinery and equipment. Nine major chapters follow a brief scene-setting introduction. The introduction in itself is most informative, spelling out the importance of such considerations as the links between scientific research and production technology, location of production, world and regional demand, economics and market expansion. Chapter 1 provides a short synthesis of world production and trade whilst Chapter 9 describes oilseed processing and products in some detail. Chapters 2 to 8 are crop specific, covering castor, groundnut, safflower, sesame, soya, sunflower, crambe, niger and jojoba. Each of these chapters follows the same format, with a brief introduction of the crop and its botany followed by the major ecological and agronomic considerations for that particular crop. Thus, detailed information is presented on soils, fertilisers, cultivation techniques, weed control, irrigation, rotations, harvesting and crop protection. A useful reference list is provided at the end of the book. This is a very informative book, which is nicely produced and well illustrated. Although the major audience is likely to be those involved directly with oilseed production, research and processing, it is also a valuable reference for students, researchers and lecturers involved more generally in agriculture.

V.E. Rubatzky and M. Yamaguchi (eds.), World Vegetables: Principles, Production and Nutritive Values.

gene expression and transformation and improvement. This first of these introduces the Rice Genome Research Programme and describes how physical, linkage and EST (expressed sequence tags, corresponding to expressed genes) maps can be constructed and exploited either in plant breeding or to facilitate the isolation of novel genes (map based cloning). It also discusses how genes can be identified and isolated using transposable elements, either endogenous retrotransposons or the Ac/Ds system introduced from maize. The second part focuses on morphogenetic mutants, describing a range of mutations which affect the development of the embryo, vegetative tissues, inflorescences and flowers. Two types of mutant are then discussed in detail in relation to other plant systems; floral initiation and the identity of floral organs. A similarly selective approach is adopted in the third part which contains detailed accounts of the structure and regulation of three classes of gene which are important in seed development and germination:abscisic acid-regulated genes, α-amylase genes and storage protein genes. These chapters are accompanied by a broader account of host: pathogen interactions which includes the isolation of resistance genes from the host and of pathogen genes involved in host recognition and infection. Finally, three chapters discuss transformation using Agrobacterium, engineering for resistance to viruses and targets for improvement. Taken together the chapters provide an overview of some of the current interests in rice molecular biology while the detailed accounts of specific systems will undoubtedly be of interest to those working on related phenomena in other plants. However, the rate of progress in rice molecular genetics is so rapid and the range of topics so selective that it really must be regarded as a snapshot of work in progress rather than a definitive account.