REPORT | PROGRAMME | ABSTRACTS | POSTERS

Symposium Day 1 – Wednesday 22 April

Day 1 Session 1: Abiotic Stress

1. Infra-red screening for stomatal mutants

Bernard Genty Laboratoire d’Ecophysiologie Moléculaire des Plantes, CEA-Cadarache, France A screen based on thermal imaging was designed to identify Arabidopsis thaliana mutants with open stomata in the dark. Thirty-seven dark unresponsive stomata (dus) mutants were isolated among a total of 72,000 EMS-mutageneised Col-0 M2 seeds. The dus mutants were grouped into two categories: one including 6 mutants with growth characteristics closely related to the wild type (WT) and another including mutants with retarded growth and/or deformed or chlorotic leaves. Within the first category that has been further analysed, we have found a dominant mutant, the dus16, characterized by the coolest rosette temperature in the dark, remaining mutants were recessive. The genetic characterization has revealed that the dus16 is allelic to the open stomata mutant ost2 previously isolated in the Ler background ; ost2 was shown to promote constitutive activation of a plasmalemma ATPase of guards cells (Merlot et al. 2002, 2007). The dus16 exhibited the highest stomatal conductance and aperture in darkness, about 5 and 4 times of the WT respectively, while the recessive ones showed an intermediate stomatal phenotype. The stomatal response to light, CO2 or ABA of the mutants was characterized.

2. Adaptive or survival trait? Designing appropriate germplasm screens for abiotic stress research and functional genomics

Bob Furbank CSIRO Plant Industry and High Resolution Plant Phenomics Centre Canberra ACT Australia Screening of mutants, transgenic plants and germplasm collections for valuable agricultural traits or to determine gene function requires high throughput, quantitative measurements which can be used in controlled environments and in the field. In the case of agricultural trait selection, systems which allow selection of adaptive traits which can provide yield gains under stress environments but not compromise yield potential, are desirable. Low resolution visual screening used for identification of drought and salt tolerance often fail to achieve these goals. Four approaches are described here and case studies are used to illustrate their utility for both germplasm screening and gene discovery; pulse modulated chlorophyll fluorescence, infrared thermography, digital growth imaging and high throughput microscopy.

3. Root phenomics of crops– opportunities and challenges

Peter J Gregory¹, A Glyn Bengough¹, Tobias Wojciechowski¹, Sonja Schmidt¹, Dmitri Grinev² and Iain Young^{2,3 1} SCRI (Scottish Crop Research Institute), Invergowrie, Dundee, DD2 5DA, UK. ² SIMBIOS, University of Abertay, Bell Street, Dundee, DD1 1HG, UK. ³ Present address: School of Environmental & Rural Science, University of New England, Armidale, NSW 2350, Australia. Genotypic differences in root systems of crops have been extensively documented but this variation has been little exploited in crop improvement programmes largely because of the difficulties of both recording root growth and screening large numbers of plants. Reliable techniques for screening large numbers of plants are still being developed but include aeroponic, hydroponic and agar plate systems, and transparent, “solid” media. Coupled with digital cameras and image analysis software, these systems permit the rapid measurement of root numbers, length and diameter in moderate (typically <100) numbers of plants. Usually such systems are employed with relatively small seedlings and information is recorded in 2D. Recent developments in x-ray microtomography have facilitated the non-invasive measurement of small root systems grown in soil-like media. Measurements in 3D are possible, meaning that angular distributions of roots can be obtained in addition to numbers and length. However, because of the time taken to scan samples only a small number can be screened (typically <10 per day, not including analysis time of the large spatial datasets generated) and, depending on sample size, limited resolution may mean that fine roots remain unresolved. Our research with barley and wheat demonstrate that while agar plates allow differences between lines and genotypes to be discerned in young seedlings, the rank order may not be the same when the same materials are grown in solid media. For example, root length of dwarfing wheat lines grown on agar plates was increased by about 40% relative to wildtype and semi-dwarfing lines, while in a sandy loam soil under well-watered conditions it was decreased (by 24-33 %). Similarly while the ranking of particular growth traits (root number, root angular spread) of 5 barley genotypes grown in gel plates, soil sacs and small soil-filled pots was similar, those grown in the gel chambers had a different order of ranking for root length to the soil-grown plants. Such differences in ranking suggest that there are significant soil environment-genotype interactions occurring, and it is therefore important to consider the typical soil conditions and stresses present in the environment where a crop is to be grown. Root growth is influenced by abiotic stresses including soil water potential, but the response depends on the growing medium and root soil contact. For example, while decreasing soil matric potential decreased root elongation of maize in both soil and vermiculite, roots and shoots grew faster in soil than in vermiculite. We are using x-ray microtomography to explore the extent to which this is a consequence of the greater root/particle contact in soil as compared with vermiculite. New optical recording systems coupled with transparent media and novel non-invasive techniques, offer increased opportunities for characterising root phenotypes but there are still substantial challenges to be met in recording large numbers, translating results from simplified media to soils, and in recording plants larger than seedlings.

4. Breeding for improved water-productivity – genes, QTL’s and phenotypes

Richard Richards, Greg Rebetzke, Michelle Watt, Tony Condon and Wolfgang Spielmeyer CSIRO Plant Industry, Canberra, ACT 2601, Australia Important gains have been made by empirical breeding, most obviously by altering phenology, but there are few examples where an understanding of the physiology and/or the genetics of putative important drought-related traits has led to improved yields. Success will firstly depend on being able to identify the most important traits in the target regions. It will then depend on accurate and fast phenotyping which in turn will lead to (1) trait-based selection being immediately transferable into breeding operations and (2) being able to identify the underlying genes or the important genomic regions (QTLs), perhaps leading to efficient marker-based selection. In this presentation we shall propose a number of traits of importance in dry environments and review whether molecular or phenotypic selection methods are likely to be most effective in crop improvement programs. We shall also discuss the development of lines/populations for accurate phenotyping which could improve the efficiency of QTL and gene discovery.

5. Salt Tolerance Screening

Mark Tester University of Adelaide Abstract to follow

6. Genetic analysis of wheat yield components in severely droughted environments

Peter Langridge, Dion Bennett, Chunyuan Huang, James Edwards, Dan Mullan and Matthew Reynolds Australian Center for Plant Functional Genomics (ACPFG), The University of Adelaide, PMB1 Glen Osmond, SA 5064, Australia. Australian Grain Technologies (AGT), Perkins Building, Roseworthy Campus, Roseworthy, SA 5371, Australia International Maize and Wheat Improvement Center (CIMMYT), Km. 45, Carretera México-Veracruz, El Batán, Texcoco, Edo México, CP 56130, Mexico Wheat is relatively well adapted to moisture stress and breeding programs using conventional approaches have resulted in significant improvements in productivity in rain-fed areas. However, there is still considerable scope for exploiting the genetic diversity that exists in wheat genomes. Genetic studies of complex traits such as response to drought have suffered from three main problems:

1. Most populations were developed using the concept of crossing highly contrasting parents to maximize genetic polymorphisms in the progeny. However the inherent drawback of this approach is that performance QTLs identified in random lines are likely to be associated with traits that have already been agronomically optimized. These developmental and adaptation traits have such a large influence on phenotypic performance that they confound detection of the target genes of interest; those associated directly with adaptation to the environment stress factors. In most instances the population sizes have also been too small for effective mapping of complex traits.
2. There has been a lack of recognition of the significant logistical problems associated with precise phenotyping on a large scale, resulting in insufficient investment to generate reliable phenotypic data and insufficient attention to develop and validate high throughput precision phenotyping protocols.
3. Now more widely acknowledged, is the different type of interactions present when mapping QTL effects which may confound and bias the final outcome. These interactions fall into three broad groups: (i) QTL x environment (GxE) interaction, (ii) QTL x QTL (epistasis, alleles from one QTL interact differently with alleles from another QTL), and, (iii) different types of epistasis x environment interaction. All these interaction effects may be more important when genotypes are subjected to different kinds of biotic or abiotic stresses.

These problems can be addressed through improvements in the structure of populations used in genetic analysis, enhancing scale and reliability of phenotyping methods and applying new analysis procedures. Our approach has been to work with populations where both parental genotypes have good agronomic performance coupled with extensive phenotyping in reliable well characterized screening environments. In addition, new trait screening methodologies that lend themselves to large scale operations have been applied. Phenotyping has been conducted across environments where many environmental factors vary but photoperiod and vernalizing temperatures are comparable. Current work has focused on the analysis of two bread wheat and one durum wheat population. Development of phenotyping tools suitable for large scale screening has been a major component of the analysis and the status of these screens across multiple environments and the genetic analysis of the yield response will be presented.

Day 1 Session 2: Biotic Stress

7. Imaging root and rhizosphere interactions to understand field processes and increase crop productivity

Michelle Watt, Rosemary White, John A. Kirkegaard, Richard A. Richards CSIRO Plant Industry, GPO Box 1600, Canberra, ACT, 2601 The challenge to solving constraints to productivity related to root and rhizosphere interactions is to link the field and laboratory. We have used the operational framework below. The field is central- to first identify the problem and to finally test new genetic or practical solutions after sufficient understanding is achieved. Imaging methods are critical to understanding the constraint in the field because these allow observation of roots and microbes in situ, in real field soils with minimal disturbance to their spatial and temporal arrangement. To date we have relied on microscopes and molecular tagging of roots taken from the field in intact soil, as microoganisms are less than 10 µm wide and below the detection of the optics of digital cameras or other portable systems. Macro imaging (mm scale) has revealed the spatial arrangement of roots in soil spaces, and when used over time (time-lapse), where and how roots growth through soil. We have combined imaging methods to understand (1) how soil bacteria and structure interact to inhibit growth in no-till conservation systems, (2) how the rhizoctonia fungus becomes more pathogenic to wheat roots in winter, (3) the types and locations of deep cereal roots and their limitations to growth and water uptake, and (4) the close association between successive generations of roots and their microoganisms that explains strong rotational effects among cereals and between cereals and non-cereals. To date, the trait we have focused on for three of the four constraints has been increased root vigour, achieved directly by new practices in the field, and by simple selection of roots or shoots in screens for new genotypes in the laboratory.

8. Chlorophyll fluorescence imaging as tool for understanding the impact of fungal diseases on plant performance

Julie Scholes Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK Biotrophic and necrotrophic fungi are agriculturally important pathogens that cause severe losses in yield. Imaging chlorophyll fluorescence provides a non invasive and non-destructive means with which to determine the impact of these pathogens on photosynthetic function with spatial and temporal resolution. In this talk I will briefly review how chlorophyll fluorescence parameters can be used to examine changes in photosynthetic efficiency, electron transport and metabolism and discuss the extent to which different chlorophyll fluorescence parameters and technologies are suited to the screening of large numbers of plants. The application of chlorophyll fluorescence imaging to understanding how fungal pathogens affect photosynthesis in both compatible and incompatible interactions will be illustrated by a series of case studies including Arabidopsis thaliana infected with white blister rust (Albugo candida) and cereals infected with powdery mildew (Blumeria graminis), rusts (Puccinia species) and Septoria leaf blotch disease (Mycosphaerella graminicola). Specifically the following questions will be addressed: When can visual and ‘metabolic’ symptoms of disease first be detected? How do fungal pathogens with different modes of nutrition alter the photosynthetic metabolism of their hosts and, to what extent can chlorophyll fluorescence imaging be used to predict crop performance in response to disease?

9. Activation tagging systems in cereals

Mick Ayliffe and Tony Pryor CSIRO Plant Industry, Box 1600, Canberra, ACT, 2601. Advances in DNA sequencing technologies have produced an ever increasing number of sequenced genomes. However, many of the genes identified in these sequencing efforts have unknown functions or functions inferred based upon sequence homology, highlighting the necessity for functional gene analysis. Mutagenesis combined with phenotypic analyses remains a key mechanism for identifying and establishing gene function. Activation tagging is a mutagenic process that uses altered gene expression, usually gene over-expression, to generate mutant phenotypes. We have developed an activation tagging system in barley based upon a maize transposable element that carries two highly expressed cereal promoters. Insertion of this mobile genetic element in the genome can lead to insertional gene inactivation, gene over-expression and gene silencing through the production of antisense transcripts. This transposable element system has also been introduced into both wheat and maize and transposon mobility observed.

Day 2 Wednesday 22nd April

Day 2 Session 3: Growth and Yield

10. Digital imaging of growth dynamics reveals gene x environment interactions on plant phenotype

Achim Walter Forschungszentrum Jülich Plants are exposed to an ever-changing environment. Plant phenotype is sculptured strongly by dynamic alterations of environmental factors. Quantitative growth analysis can provide a sensitive tool to understand gene x environment interactions which establish plant structure and function during growth processes. As environmental variations take place across a wide range of spatial and temporal scales, it is important to investigate growth dynamics at spatial and temporal scales that are relevant for specific questions. In this work, a number of growth imaging methods and concepts is presented and their sensitivity to determine gene x environment effects is highlighted. Examples include highly resolved growth analysis of leaf discs floating on nutrient solution, simultaneous analysis of leaf growth and photosynthesis in rosette plants and a novel, non-invasive analysis method for shoot fresh weight. The portfolio of the methods available at the Jülich Plant Phenotyping Center allows precise analysis of plant performance in fluctuating and stressful conditions and enables a phenotype-based quantitative comparison of the performance of different plant lines in defined conditions. These approaches facilitate rapid selection of optimal germplasm for crop and bioenergy production under specific environmental conditions and support refining light-, water- and nutrient use efficiency. Approaches for automatic and quantitative assessment of the plant phenotype will strongly advance plant breeding and basic research alike. Plant shape and photosynthesis are among the most prominent features of the plant phenotype. The structure of the aboveground plant organs is laid down via growth processes that show a close interaction with the environment and with internal regulatory mechanisms determining plant performance. As plants are exposed to an ever-changing environment, it is crucial to elucidate their reaction to altering environmental factors on appropriate scale and with a meaningful dynamics. Here, we present novel growth imaging methods and showcase results highlighting the sensitivity of these technologies to determine gene x environment effects. Novel concepts to characterize plant reaction towards drought stress show that… Analysis of leaf disc growth dynamics… Analysis of shoot biomass… Integrated approaches of growth analysis and –omics studies will allow rapid selection of optimal germplasm for crop and bioenergy production under specific environmental conditions and to optimize light- water- and nutrient use efficiency in the future.

11. Preliminary use of ground-penetrating radar and electrical resistivity tomography to study tree roots in pine forests and poplar plantations

Terenzio Zenone^A,B,Gianfranco Morelli^C, Maurizio Teobaldelli^B, Federico Fischanger^C, Marco Matteucci^B, Matteo Sordini^D, Alessio Armani^C, Chiara Ferrè^E, Tommaso Chiti^F and Guenther Seufert^{B A}Department of Forest Science and Environment, University of Tuscia, Viterbo, Italy. ^B European Commission DG-Joint Research Centre, Institute for Environment and Sustainability, Climate Change Unit, T.P. 050 Via E. Fermi, I-21027 Ispra (Va), Italy. ^C Geostudi Astier, Via della Padula, 165. 57125 Livorno, Italy. ^D LAPETLAB, Landscape Archaeology and Remote Sensing Laboratory, University of Siena, Via Roma 56, 53100 Siena, Italy. ^E DISAT, Department of Environmental Sciences, University of Milano-Bicocca, P.za della Scienza, 1 20 126 Milan, Italy. ^F Department of Soil Science and Plant Nutrition, University of Florence, Piazzale delle Cascine, 16–50144 Firenze, Italy. In this study, we assess the possibility of using ground penetrating radar (GPR) and electrical resistivity tomography (ERT) as indirect non-destructive techniques for root detection. Two experimental sites were investigated: a poplar plantation [mean height of plants 25.7 m, diameter at breast height (dbh) 33 cm] and a pinewood forest mainly composed of Pinus pinea and Pinus pinaster Ait. (mean height 17 m, dbh 29 cm). GPRmeasures were taken using antennas of 900 and 1500MHz applied in square and circular grids. ERT was previously tested along 2-D lines, compared with GPR sections and direct observation of the roots, and then using a complete 3-D acquisition technique. Three-dimensional reconstructions using grids of electrodes centred and evenly spaced around the tree were used in all cases (poplar and pine), and repeated in different periods in the pine forest (April, June and September) to investigate the influence of water saturation on the results obtainable. The investigated roots systems were entirely excavated using AIR-SPADE Series 2000. In order to acquire morphological information on the root system, to be compared with the GPR and ERT, poplar and pine roots were scanned using a portable on ground scanning LIDAR. In test sections analysed around the poplar trees, GPR with a high frequency antenna proved to be able to detect roots with very small diameters and different angles, with the geometry of survey lines ruling the intensity of individual reflectors. The comparison between 3-D images of the extracted roots obtained with a laser scan data point cloud and the GPR profile proved the potential of high density 3-D GPR in mapping the entire system in unsaturated soil, with a preference for sandy and silty terrain, with problems arising when clay is predominant. Clutter produced by gravel and pebbles, mixed with the presence of roots, can also be sources of noise for the GPR signals. The work performed on the pine trees shows that the shape, distribution and volume of roots system, can be coupled to the 3-D electrical resistivity variation of the soil model map. Geophysical surveys can be a useful approach to root investigation in describing both the shape and behaviour of the roots in the subsoil.

12. Chlorophyll fluorescence screening of Arabidopsis thaliana for photorespiratory and photoinhibition mutants

Murray R Badger, Shunichi Takahashi, Hossein Fallahi and Sarah Kaines ARC Centre of Excellence in Plant Energy Biology, Molecular Plant Physiology Group, School of Biology, Australian National University For plants with the C3 photosynthetic pathway, the ability to perform efficient photosynthesis under ambient conditions of CO2 and O2 is critically dependent on the operation of photorespiratory metabolism which is linked to the metabolic processing of phosphoglycolate produced by Rubisco oxygenase. Mutant plants impaired in aspects of photorespiration generally do not survive or grow at air and must be maintained under a high CO2 atmosphere where Rubisco oxygenase is suppressed. The selection of photorespiration mutants in Arabidopsis was one of the first demonstrations of the usefulness of forward genetic screens in a genetic model plant species. This screen was based on growing EMS mutagenised seed at high CO2 and selecting for plants which showed chlorosis when exposed to air for several days. Our recent studies of Arabidopsis photorespiratory mutants have showed that all previously isolated Arabidopsis photorespiratory mutants when exposed to air show a more or less rapid decline in the functionality of photosystem II (PSII) as measured by dark adapted chlorophyll fluorescence parameter Fv/Fm. The reason for this appears to be the production of oxidizing conditions in the chloroplast when photorespiratory mutants are exposed to air, which leads to a severe inhibition of the PSII protein repair pathway. We have used this observation to develop a forward genetic screen for a new set of Arabidopsis EMS mutants which we hope will reveal a new set of mutants impaired aspects of photorespiration, CO2 capture and photoinhibition tolerance. The new screen takes 8 day old Arabidopsis seedlings grown at high CO2, and exposes them to zero CO2 conditions for 24 hrs under continuous light. Individual seedlings, which are arrayed in a grid, are then imaged for their dark adapted Fv/Fm values. Seedlings with reduced Fv/Fm are retained and grown through to M3 seed collection at high CO2. The resulting M3 seed was re-screened for Fv/Fm both at high CO2 and after exposure to zero CO2 for 24 hrs and the mutants classified. Two major classes of mutants were identified, those where Fv/Fm was impaired by treatment at low CO2 and those where it was already reduced at high CO2. So far we have screened over 25,000 M2 seeds and recovered over 100 mutants in each of the major categories. The possibilities that these mutants may be impaired in aspects of photorespiration and photoinhibition and our future efforts to characterize these mutants will be discussed.

13. Non-invasive measurements of chloroplast function in leaves

David M. Kramer Institute of Biological Chemistry. Washington State University, Pullman, WA 99164 This presentation will cover recent developments in the non-invasive measurement of photosynthetic processes under steady-state conditions. The light reactions of photosynthesis involve many species which respond to changes in physiological state. Many of these species can be probed using non-invasive techniques, allowing us to investigate the inner workings of plants as they function in living plants. I will briefly review some recent advances in probing electron transfer, proton transfer, ATP synthesis, regulation of antenna function, photodamage and repair. I will then show how these techniques allowed us to 1) demonstrate that feedback limitation of photosynthesis is controlled by regulation of the ATP synthase; and 2) isolate a new class of Arabidopsis mutants with extremely high cyclic electron flow around photosystem I (CEF). Analysis of these ‘high cyclic electron transfer’ (hcef) mutants has allowed us to test (and in some cases eliminate) current models about the enigmatic CEF process. During the discussion, I hope to make connections between the regulatory networks reveled by these techniques and future phenomics efforts to improve plant responses to the environment.

14. Imaging roots and root function in soil – new windows to plant performance through phenotyping

Uli Schurr Forschungszentrum Jülich, Germany Plant phenotyping opens new windows to quantitatively analyse plant performance. Novel technologies need to be combined with adequate simulation or monitoring of the environment and genetically clearly defined plant material. The “magic triangle” of phenotyping Genetics-Environment-Sensors is the basis for high throughput as well as high performance analysis of plants with relevance for field performance of plants as well as basic plant research. In a first part the talk I will present the integrated approach to plant phenotyping as it is implemented in the Jülich Plant Phenotyping Center (JPPC, Jülich, Germany) and illustrate the CropSense project that develops phenotyping for complex agriculturally important traits for breeding and plant management (FZ Jülich and University of Bonn with academic and industrial partners). In the second part of the talk root structure and function will be addresses as a special application of plant phenotyping, but illustrating several major principles of the generic approaches described before. Root structure and function are crucial for plant performance in agricultural and natural environments: structure-function relations of roots are the basis for abiotic and biotic stress performance, water and nutrient use efficiency. While the relevance of such traits is ever increasing in the context of environmental challenges and sustainable agriculture the knowledge on root structure and function is scarce. This is partly due to the fact that roots are the hidden half of the plant and embedded in “intransparent” soil. In addition the soil is a medium that is very different from the aboveground environment of the shoot and characterised by its spatial and temporal variation – exerting very different selection pressure on the root when compared to the shoot environment. This special situation for root phenotyping can be addressed by establishing chains of experimental approaches that combine high throughput approaches with small scale mechanistic analysis and novel tomographic approaches. The paper will also highlight the necessity of proper simulation of the environment with respect to spatial and temporal properties in order to obtain data from phenotyping experiments that are relevant for plant performance in the field.

Day 2 Session 4: Ecosystem Dynamics and Climate Change

15. Evaluation of Imaging Lidar for Plant Structural Measurement

Darius Culvenor CSIRO Sustainable Ecosystems One of the roles of the Australian Plant Phenomics Facility is the development of tools and technologies to undertake rapid assessment of plant structure, function and performance. This study evaluates the capability of relatively new imaging lidar (light detection and ranging) technology in the context of plant structural measurement. The SR4000, developed by Mesa Imaging, is a ranging camera that uses modulated light from a matrix of Light Emitting Diodes to calculate a distance value for each imaged pixel. The camera was evaluated in terms of its spatial resolution, range resolution and data acquisition time. Acquisition of multiple overlapping frames using a scanning platform was also investigated as a means of enhancing spatial detail.

16. Monitoring, Understanding and Modeling Agroecosystems

Joe Berry & Roland Peiruschka Carnegie Inst. for Science, Dept. of Global Ecology and Elliott Campbell, College on Engineering, UC Merced Our ability to think broadly about ways to increase agricultural yields in the face of diminishing resource availability while, at the same time, adapting to climate change will require tools that enable us to think broadly about our options. In other sectors such as manufacturing, information technology and aeronautics, interactive use of modeling and sophisticated observation systems have provided the basis for rapid progress. Modeling of crop growth and yield could be improved by advances in the understanding of the fundamental mechanisms of plant processes arising from studies of phenomics. In addition we need test and improve models of agricultural systems at various scales by improving existing, and developing new, observational approaches to monitor crop systems. As example of how coordination of research at different scales is needed to make progress, we present a study of variation in the concentrations of carbonyl sulfide and carbon dioxide in the atmosphere over the mid continent of North America during the growing season. We develop the argument that these measurements could provide new constraints on the contributions of photosynthesis and respiration to net carbon balance and an alternative to latent heat flux for estimating canopy conductance. However, current models are not up to this task as a sufficient understanding of the mechanisms of stomatal regulation is wanting. Companion studies of stomatal regulation at the leaf scale provide some new insight into how this regulatory process works and and into how models might be improved.

17. Hyperspectral imaging of variation in foliar pigmentation in response to freezing temperatures: from stress responses of individual leaves to monitoring vegetation responses to climate warming

Marilyn C. Ball and Katharina Siebke Functional Ecology Group, Research School of Biological Sciences, School of Biology, Australian National University, Canberra, ACT 0200 Australia Leaves of frost tolerant evergreen species, such as snow gum (Eucalyptus pauciflora), undergo seasonal changes in pigmentation that reduce vulnerability to photo-oxidative damage during exposure to low winter temperatures. Anthocyanin accumulates in the epidermis. Chlorophyll concentrations decrease, with chlorophyll a/b ratios decreasing in photosynthetic cells beneath layers of anthocyanin. Finally, concentrations of zeaxanthin increase concomitant with the appearance of pigment complexes that apparently enable storage of chlorophyll in over-wintering leaves. Using hyperspectral imaging techniques, we found that minor, non-saturating features of reflectance spectra were the best predictors of pigment composition in intact leaves. In the case of photosynthetic pigments, our analyses identified spectral features that were associated with fluorescence from chlorophyll a, and its modification by chlorophyll b or by the altered configuration of zeaxanthin containing pigment complexes associated with protective storage of chlorophyll. While summer acclimated leaves showed little variation in pigmentation, spatial variation in pigment composition was consistent with differential exposure to damaging freezing temperatures during autumn. These methods may enable better remote detection of both sublethal freezing injury and deacclimation of temperate evergreens to winter temperatures in spring, two factors of major importance in monitoring responses of vegetation to climate warming and rising atmospheric CO2 concentrations.

18. Adaptive genes and the environment: Mapping in the era of global climate change

Michael Purugganan Department of Biology and Center for Genomics and Systems Biology, New York University, 100 Washington Square East, New York, NY USA 10003 As global climate change occurs, species will have to evolve to adapt to changing environmental conditions. A major question is whether species harbor genetic variation that can serve as reservoirs for adaptive change. Here we explore adaptive gene mapping techniques, focusing on candidate gene association studies and domestication loci in two plant species, Arabidopsis thaliana and rice. We describe candidate gene associations for flowering time – a climactically sensitive trait – in A. thaliana. We will also report on selective sweep mapping of genes associated with domestication in rice, a process that identifies genes selected for by humans as they began cultivation during the last major global warming episode in the Neolithic.

19. IR imaging of plant canopies: scaling up the remote diagnosis and quantification of plant stress to the field and beyond

Hamlyn G Jones Division of Plant Sciences, University of Dundee at SCRI, Dundee, Scotland The use of thermal remote sensing, especially when combined with spectral reflectance or even fluorescence measurements is becoming an increasingly powerful tool to diagnose and monitor the effects of environmental stresses on plants. As such the approach is increasingly being used for phenotyping plant populations both in controlled environments and in the field. Various approaches to the combination of thermal remote sensing with spectral remote sensing of plant canopies, especially to distinguish plants from their background, and also to enhance the diagnostic powers of the technology, will be outlined. Emphasis will be on the scaling up of such techniques to the field and larger scales, with a particular concentration on the use of thermal sensing to study stomatal behaviour, while the main limitations of remote sensing approaches for plant phenotyping, especially at larger scales, will also be addressed. The advantage of using a multi-sensor approach for stress diagnosis will also be highlighted and some possible applications summarized.