Workshop Timetable

Photosynthesis 2007 Workshop Timetable

Workshops taking place on Monday, Tuesday and Wednesday will be located in the purpose built workshop area at the back of Hall 5. Workshops taking place on Thursday will be on the relevant exhibitor’s stands.

Each workshop will run three times during the 5pm – 7pm session, starting at 5pm, 5.45pm and 6.30pm. You must have booked a place on each workshop and if you are not present at the start of the workshop your place will be released on a first come first served basis. To book a place on a workshop, please email k.steel@sebiology.org with the name, date and time of the workshop you wish to attend.

Monday 23^rd July 17:00 - 19:00

Hansatech Instruments
More details to follow

Technologica

Chlorophyll Fluorescence Analysis – Stress and Screening
Monitoring and screening considerable numbers of plants as rapidly as possible has become increasingly desirable for both scientific research and industrial applications. Chlorophyll a fluorescence is commonly used to screen and analyse plant material subjected to a variety of stresses or growth treatments as well as the identification of mutants and transgenic material. Using a CF imager marketed by Technologica Ltd. Essex, we will demonstrate the isolation and zoning of individual light or water stressed seedlings grown in a 96 well plate. Images of photosynthetic efficiency, photochemical and non-photochemical quenching will be created to characterise plants grown under the different treatments. Using seedlings germinated on agar in Petri plates under high and low lighting regimes we will demonstrate how rapid recognition and isolation of regions (colonies) of interest can greatly facilitate analysis. Using automated procedures we will then construct individual light response curves simultaneously for all seedlings within the Petri dish and determine key photosynthetic parameters.

Tuesday 24^th July

Qubit Systems Inc
More Than Half of the Equation: measurement of photosynthetic oxygen exchange from a leaf in an open flow gas exchange system

Measurements of photosynthetic rate in open flow gas exchange systems are usually limited to the analysis of CO2 uptake, since infra red CO2 analyzers can easily discriminate small (e.g. 1ppm) changes in CO2 against atmospheric levels (e.g. 380 ppm). Until recently, measurements of open flow photosynthetic O2 release were not possible, since analyzers capable of discriminating 1 ppm O2 against atmospheric O2 levels (209,500 ppm) did not exist. This workshop will demonstrate the use of a novel differential O2 analyzer (S104 DOX) developed by Qubit Systems Inc. that has the accuracy and resolution required for such measurements.

The S104 DOX can be used in conjunction with an infra red CO2 analyzer to provide simultaneous measurements of CO2 and O2 flux from leaves and other photosynthetic samples. Since photosynthetic O2 release is related closely to electron transport, measuring variations in O2 flux together with CO2 uptake provides insights into the fate of reductant generated photochemically. Such measurements thereby provide a non-invasive method for metabolic analysis.

The demonstration will be conducted by Dr. Stephen Hunt of the Biology Department of Queen's University, Kingston, Ontario, Canada. Dr. Hunt is a co-author on the patent for the S104-DOX and has collaborated in several published studies in which the instrument has been used to investigate both photosynthetic and respiratory metabolism. Dr. Hunt is also co-founder and CEO of Qubit Systems Inc, who manufacture and market the Differential Oxygen Analyzer.

Heinz Walz GmbH
Chlorophyll-a-fluorescence imaging in combination with gas exchange measurements

Local defence-related depression of photosynthesis and metabolic rearrangement in infected leaves visualized by chlorophyll-a-fluorescence imaging

Hardy Schön¹, Judith Scharte¹, Jutta Essmann¹, Engelbert Weis¹ and Katharina Siebke²
(1) Institut für Botanik, Schlossgarten 3, 48149 Münster, Germany
(2) Heinz Walz GmbH, Eichenring 6, 91090 Effeltrich, Germany
schonh@uni-muenster.de, jschart@uni-muenster.de, jessmann@uni-muenster.de, weise@uni.muenster.de, ksiebke@walz.com

Chlorophyll-a-fluorescence imaging has been proven to be an excellent tool for monitoring local changes in photosynthesis and leaf metabolism during leaf development or various stresses. Here, a local and rapid depression of photosynthesis in a resistant tobacco leaf after infection with Phytophthora nicotianae is demonstrated. Simultaneously, to the first appearance of H₂O₂, stomata at the infection site close and the photosynthetic flux is reallocated from CO₂ assimilation in favour of photorespiration. Later (>6 hpi), the photosynthetic electron transport declines, most likely due to a disturbance in the high-potential chain, while PSII is still intact. Subsequently (>12 hpi), photosynthesis completely collapses. These changes are accompanied by an enhancement of carbohydrate consuming pathways (e.g. respiration) and various cellular changes (e.g. oxidative burst, sealing by callose deposition). The decline in photosynthesis and the metabolic shift to a heterotrophic state are highly localized processes, which occur in single mesophyll cells and precede hypersensitive cell death. We propose that in photoautotrophic leaves, assimilatory metabolism must be switched off to initiate a more heterotrophic metabolism, which is required for effective plant defence.

Localized changes in the photosynthesis of intact leaves can well be demonstrated with chlorophyll-a-fluorescence imaging. The insight gained with this technology can be further improved by gas exchange measurements in a controlled environment. We will demonstrate simple experiments (e.g. induction curve of photosynthesis, measurements of ETR, qN) of elicitated leaves with the gas exchange and fluorescence system, GFS-3000, and the Imaging-PAM, to point out the value of these methods in modern botanical research.

Wednesday 25^th July

Agrisera
Quantitative Immunoblotting in Plant Sciences using Global Antibodies

Amanda Cockshutt¹ & Joanna Porankiewicz-Asplund²

1. Environmental Proteomics NB Inc. Sackville NB CANADA, www.environmentalproteomics.ca

2. Agrisera AB, Vännäs, SWEDEN, www.agrisera.se

Summary:

Detecting and quantitating important proteins in plants and other photosynthetic organisms has become more practical and powerful with the application of quantitative immunoblotting using global antibodies which recognize proteins evenly across a wide range of taxa. While many tools are commercially available for the examination of medically relevant proteins in mammals, such tools have been lacking for the study of pressing questions in other organisms. In this workshop, we present the advantages of quantitative immunoblotting and the methodology necessary to apply these tools to species of interest. We will offer tips for trouble shooting difficult to characterize samples, and examples of the data obtained with this approach.

ADC Bioscientific Ltd
Measuring the photosynthesis of Arabidopsis thaliana and other small-leaved species

Matthew P Davey (Department of Animal and Plant Sciences, University of Sheffield, UK)

Measuring plant leaf gas exchange is one of the staple methods in plant physiology. Alterations in photosynthetic rates and water loss can provide an indication of stress or acclimation in many plant species. Measuring gas exchange on crop or tree species has traditionally been easy, mainly due to their large flat leaves, quick settling time and field locations. However, measuring the gas exchange on wild species and ecotypes, many of which have a variety of leaf forms and habits does prove to be difficult. As more non-crop species are being used in molecular biology studies, the accuracy and reproducibility of plant gas exchange measurements is increasingly important for identifying relevant phenotypes and traits.

Using the ADC LCpro+ with a small flexible chamber enabled us to obtain accurate measurements of gas exchange on such small leaves. Arabidopsis thaliana and Arabidopsis lyrata petraea both have small, occasionally lobed leaves within a tight basal rosette. Results will also be shown where the rates of photosynthesis, transpiration and stomatal conductance were reduced after cold shock in A. thaliana ecotypes but not in A. petraea. This indicates that A. petraea is a cold tolerant species. Methodologies and procedures, including the benefits and practical limitations, for using the LCpro+ in controlled-environment cabinets set at various temperatures will be presented.

Thursday 26^th July

Education Workshop

17:00 - 17:20

Professor David Walker
Hansatech Instruments Ltd Stand

In Praise of Search Engines and Hyperlinks

Oxygen electrodes, photosynthesis and related topics

D.A. Walker, University of Sheffield/Hansatech

Over the last decade the availability and increasing speed of Broadband has made it commonplace to turn to the Internet for information. Digital books with hyperlinks offer a means of structuring this retrieval process and even leavening the most complex science with cartoons and sound for those who might not otherwise readily turn to a more formal style of presentation. An example of this approach will be illustrated.

17:20 - 17:40
Dr Steve Hunt
Qubit Systems Inc Stand

Novel approaches to practical classes in photosynthesis

S. Hunt, Qubit Systems Inc.

Teaching the physiology and ecophysiology of photosynthesis through hands-on investigations in undergraduate labs requires, ideally, that students measure rates of CO2 and water exchange from plants under various conditions of light, temperature, relative humidity, air flow rate and CO2 partial pressure. More complex labs may also include the simultaneous measurement of gas exchange and chlorophyll fluorescence parameters. Research instrumentation that incorporates all the sensors and analyzers required for such measurements is prohibitively expensive for educational purposes, especially when several lab groups of two to four students per group are required to use the equipment at the same time.

The prime purpose of research equipment is to provide accurate data rapidly, without instructing how the data are calculated or derived. By contrast, effective lab teaching requires that students understand the technical aspects of how measurements are made, preferably by constructing a gas exchange system themselves. Also, the students should understand how photosynthetic parameters are calculated, rather than accepting values from a “black box.”

Qubit Systems’ Plant CO2 Analysis Package will be demonstrated. This includes all the components of a gas exchange system for accurate measurement of CO2 exchange rate, transpiration, water use efficiency, leaf conductance and related parameters. Students can construct the system easily within minutes, after which they acquire data via a computer interface. Rate calculations may be done manually or automatically in software. Prices of complete packages start at $2650 US, a fraction of traditional research instrumentation. Chlorophyll fluorescence may be measured simultaneously by adding components totaling $2580 US.

17:40 - 18:00

Dr Lada Nedbal
Photon Systems Instruments sharing stand with Qubit Systems Inc

Fluorometric devices to teach photosynthesis – a student competition

Ladislav Nedbal^1,2 and Martin Trtílek²
¹ Inst. Systems Biology and Ecology and Inst. Physical Biology, Zámek 136, 37333 Nové Hrady

² Photon Systems Instruments, Koláčkova 39, 62100 Brno, Czech Republic

We shall describe and provide three fluorometric instruments that are used in photosynthesis research and education: an Imaging FluorCam, an AquaPen, and an Algal Bioreactor (see http://www.psi.cz/ for details). We shall also provide numbered samples of algae and cyanobacteria in liquid cultures as well as in Petri dishes, together with a list of alternative sample descriptions. The participants in the competition will design and do simple experiments to determine correspondence between samples and sample descriptions. The experiments will be conducted in the Exhibition Area anytime until Thursday July 26, noon. A winner of the student competition will be drawn from correct entries on Thursday afternoon. The winner will receive a portable fluorometer FluorPen worth €1000.

18:00 - 18:20
Dr Ulrich Schreiber
Heinz Walz GmbH

Energy conversion in photosynthesis assessed by Imaging-PAM and Dual-PAM-100

Dr Ulrich Schreiber, Heinz Walz GmbH

Since the introduction of PAM fluorometry more than 20 years ago, chlorophyll fluorescence (Chl F) has not only been successfully applied in numerous fields of research, but also for teaching the principles of photosynthesis. Economical devices (like Teaching-PAM or Junior-PAM) are available that allow students to gain hands-on experience. The Imaging-PAM is particularly suited for visualizing heterogeneities and spatiotemporal changes in photosynthetic parameters.

While Chl F provides information on the fate of excitation energy in PS II, equivalent information on PS I can be obtained with the help of P700 absorbance measurements and a special saturation pulse technique. The Dual-PAM-100 allows simultaneous measurement of P700 & Chl F and determination of the quantum yields of photochemical energy conversion Y(I) & Y(II), of regulated energy dissipation into heat Y(ND) & Y(NPQ), as well as non-regulated energy dissipation into heat Y(NA) & Y(NO).

The educational potential of Chl F and P700 measurements is demonstrated by simple experiments with partially heat-pretreated leaves. Chl F imaging reveals that moderate heating causes a decrease of Y(II) paralleled by an increase of Y(NPQ). While more severe heat-pretreatment only marginally affects Y(II), Y(NPQ) is suppressed and instead Y(NO) stimulated. Measurements with the Dual-PAM-100 reveal in moderately heated samples a decrease of Y(I) and increase of Y(ND), while in more severely heated samples Y(ND) is suppressed and Y(NA) stimulated. This underlines the role of the regulatory mechanism reflected by NPQ for plant protection against environmental stress. This mechanism not only down-regulates PS II, but PS I as well.

18:20 - 18:40
Dr Reto Strasser

Experimental resolution and theoretical complexity determine the amount of information extractable from the chlorophyll fluorescence transient OJIP: A Demonstration with Instruments

M. Tsimilli-Michael^1,2 and R.J. Strasser¹

¹Bioenergetics Laboratory, University of Geneva, Jussy-Geneva, Switzerland

²Ath. Phylactou 3, Nicosia 1100, Cyprus

What we know for any aspect in experimental sciences is the models we make for it. Models of any theoretical complexity level can be formulated, but they are meaningful only if the experimental signals provide the according resolution. We here present the contribution of our laboratory in utilising chlorophyll fluorescence transients to formulate photosynthetic models. The starting complexity levels were those of the open/closed reaction centres (RCs) model, supported by the experimental determination of the fluorescence rise extremes (F₀, F_M), and the separate/grouped units model, assessed from the fluorescence rise shape in DCMU-treated samples. Using fluorimeters with improved time resolution (10ms) and actinic-light intensity, the polyphasic shape (OJIP) of the fluorescence rise was revealed in detail. This permitted us to formulate models of higher complexity, composed of more functional building blocks, hence assessing/describing higher heterogeneity levels: Detailed analysis of the O-J phase allowed calculation of electron transport yields, recognition/estimation of silent RCs-“heat-sinks” and determination, also in DCMU-absence, of the grouping probability p_G. We could therefore formulate and check a 3-types-model (open/closed/silent RCs) with energetically connected/grouped units (any p_G value), applicable for different physiological states. The later recognised K-band (0.3ms) was related with RCs dissociated from the oxygen-evolving-complex and the I-step (30ms) to PSI-RCs inactive in supplying electrons into the CO₂-fixation process. The model complexity was enriched with more functional building blocks from studies during State 1-State 2-transition. Simultaneous P700 and plastocyanin absorption measurements and delayed fluorescence signals permit us now to check conclusions made from the OJIP multilevel utilisation.

18:40 - 19:00
Govindjee
Society for Experimental Biology

Photosynthesis Education on the Web

Each workshop will run three times during the 5pm – 7pm session, starting at 5pm, 5.45pm and 6.30pm. You must have booked a place on each workshop and if you are not present at the start of the workshop your place will be released on a first come first served basis. To book a place on a workshop, please email k.steel@sebiology.org with the name, date and time of the workshop you wish to attend.