To understand the aphid response to droughted plants at thegenetic level, the gene expression of Myzus persicae exposed to twodifferent drought regimeswas analysed on the host plant Brassica nigrausing microarrays. Changes in aphid gene expression are interpretedwithin the context of changes in the physiological status of the plant.These changes were assessed using water potential measurements,amino acid concentrations and fresh–dry weight ratios. This informa-tionwill help to identify aphid'smechanisms of feeding underdrought.
Email Address for correspondence: [email protected]
doi:10.1016/j.cbpa.2009.04.587
P5.1116:10 Monday 29th June 2009Dynamic acclimation in Arabidopsis thaliana
Beth C. Dyson (University of Manchester), Kleovoulos Athanasiou(University of Manchester), Rachel E. Webster (University ofManchester), Giles N. Johnson (University of Manchester)
Dynamic acclimationof photosynthesis is theprocess bywhich someplants can alter their photosynthetic capacity (Pmax) upon transfer todifferent light conditions. Arabidopsis thaliana L. cv. Wassilewskija (WS)is able to dynamically acclimate, whereas A. thaliana L. cv. Columbia 0(Col 0) is not.
Microarray analysis identified a glucose 6-phosphate/phosphatetranslocator (GPT2) that is highly up-regulated during dynamicacclimation. A T-DNA insertion knockout of GPT2 in WS is unable toincrease Pmax when transferred from low to high light. GPT2 istherefore essential for dynamic acclimation.
To investigate the physiological importance of dynamic acclima-tion, plants of Col 0, WS and the GPT2 knockout were grown over thewinter in an unheated greenhouse under naturally variable lightconditions. Their seed production was compared to that of plantsgrown in the lab at 100 µmol m−2 s−1 light/20 °C/8 hour days.
When grown in the lab, Col 0 produces far fewer seeds than WS.However, there is no difference in seed production between WS andthe GPT2 knockout.
When grown under naturally variable light conditions, WS hadsignificantly higher seed production than when grown in the lab.Both Col 0 and the WS GPT2 knockout had substantially lower seedproduction than their respective lab controls.
This indicates that dynamic acclimation of photosynthesis playsan important role in maximising the reproductive fitness of plantsgrowing under naturally variable conditions.
Email Address for correspondence: [email protected]
doi:10.1016/j.cbpa.2009.04.588
P5.1216:30 Monday 29th June 2009
doi:10.1016/j.cbpa.2009.04.589
P5.1309:00 Tuesday 30th June 2009A real-time biosensor for plant hormones
Richard M. Napier (University of Warwick), George O. Badescu(University of Warwick)
If we are to understand the timing, direction and extent ofresponses to hormonal stimuli we need to capture quantitativeinformation from living, responding tissues. Previously, quantitationof plant hormones has tended to be either post-event, timefractionated assays of plant homogenates (mass spectrometry, HPLC,GC, ELISA etc.) or assays have been qualitative using, principally,promoter–reporter constructs. Much detailed physiology has beendetermined from interpretations of these reporters, but they remainlargely qualitative and post-event with little or no temporalresolution. Quantitative biosensors are widely used in other areas ofbiology and, although no one system will suit all applications, theircontinued development and application to plant physiology isoverdue. A novel configuration and application of a surface plasmonresonance instrument (Biacore 2000) is described such that itbecomes a biosensor platform capable of measuring in real-timecontinuous changes of concentration of aqueous analytes from livingtissue. The examples presented are for the plant hormones auxin andABA. The biosensor gives time-resolved dataflow with a dynamicrange of approximately four orders of magnitude. We will show howsamples from live plant tissues are collected to flow continuouslyover the Biacore chip.
Email Address for correspondence: [email protected]
doi:10.1016/j.cbpa.2009.04.590
P5.1409:30 Tuesday 30th June 2009Seasonal growth of temperate terrestrial orchids as affected by theold tuber
Alfred A. Darkwa (University of Sussex), Peter Scott (University ofSussex)
Many terrestrial orchids are rare or even endangered. They have aunique relationship with specialized mycorrhizae, require optimalgrowth conditions, and several of their genera do not propagate easily,all these contribute to their rareness. There is therefore an urgent needto put in place complementary conservationmeasures which require agood understanding of the life cycle of the orchids to save them. Thisunderstanding is presently unavailable. A United Kingdom orchidspecies (Anacamptismorio)was used as themodel for this study,whichlooks at the growth of temperate terrestrial orchids under normalconditions and the influence of old tuber on growth. Findings revealedthat the plants havewell defined growthpatterns and can groweven inenvironmental conditions that are unfavourable for the growth ofother plants. The old tuber of these orchidsmayonly support the initialestablishment of the canopy and the subsequent growth of below-ground tissue. The leaves rapidly reach a point of self-sufficiency andsupport their own growth. Although the old tuber does not influenceflowering directly, it does so indirectly because the planted tubermustbe of certainweight to produce plants that can flower. Initial tuber sizeand final canopy size did relate suggesting that larger tubers yieldlarger canopies and enhance flowering. This implies that any damageto the canopy (through grazing) from October to December willseverely affect aerial growth consequently leading to smaller plantsthat are unlikely to flower and yield enough tubers.
Keywords: Anacamptis morio";; Terrestrial orchids";; Old tuber";;Growth
Email Address for correspondence: [email protected]
doi:10.1016/j.cbpa.2009.04.591
Abstracts / Comparative Biochemistry and Physiology, Part A 153 (2009) S209–S218S212
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