1. High-resolution phenotyping Water flow dynamics Chloroplast movementHae Koo Kim, Joonghyuk Park, Jeong Eun Ryu, Sungsook Ahn, Ildoo Hwang and Sang Joon Lee

2. Plants in Environmental & Energy Sciences Diversity in vascular system: Model plants Central Role in the Water Cycle on Earth (conifers): water transport over 100m -Gymnosperms Green revolution yet to come -Angiosperms (monocots & dicots): few cm to tens of m for smallholder farmers? Importance of the Plants Agriculture: up to 70% of the Water & mineral transport : Xylem water use Blue revolution in Agriculture: Drought stress in water-limited environments - Drop by Drop - Gene by Gene Pennisi (Science, 2008) Water transport in plants Cohesion-Tension Theory, Bhm, 1893; Dixon and Joly, 1895) Scholander et al. (1965) Science 148 Johnson & Dixon (1965) Nature 208Scholander et al.,1965Balling & Zimmermann, 1990Pockman et al. (1995) Nature 378 Holbrook et al. (1995) Science 270 3. Visualization of Water flow at different level on Earth6,650 km 4. Synchrotron facilitiesPAL, PohangPF, TsukubaSSRF, Shanghai 5. Visualization of water flow dynamics using synchrotron X-ray imaging Synchrotron X-ray imaging -Absorption and phase-contrast based imaging -High temporal (ms) and spatial resolution (m) -Ideal to visualize xylem vessels of monocots -Real-time dynamics of refilling processKim & Lee, 2010 New Phytologist 6. Phenotyping Xylem Structure/Function relationshipsSap flow dynamics in xylem vessels XylemSafetyEfficiencyStructure FibersVascular bundle[WATER TRANSPORT]Efficiency vs. Safety trade-off in water transport FunctionHigh resistanceModularitySupportRepairParenchymaVessels StorageTransport Low resistanceConnectivityPhloemFUNCTION of Xylem: Efficiency & Safety of water transport STRUCTURAL characteristics of XYLEM Sap flow dynamics 7. Efficiency and Safety trade-offs in water conduits Number of pits 16-20 11-15 6-10 1-5 0Cluster 1Cluster 2-2Cluster 2-1UR 82P,QR4PcPCluster 38Metaxylem vessel number and lumen area Diameter A:B:C=4:2 :1 Vessel area A : B : C = 16 : 4 : 1 Flow rates A : B : C = 256 : 16 : 1ClusterNumber (ea)AVG (m2)MAX (m2)MIN (m2)173226.7 (102.3)496.766.2283201.8 (87.4)489.676.03126108.7 (37.5)318.352.97 8. Visualization of internal structure of plants and flow dynamicsKim and Lee., 2010 New PhytologistAhn et al., 2010 ACS Nano 9. -Long distance water transport (efficiency) -Short distance, higher resistance, local water distribution (safety) 10. Synchrotron X-ray CT: Vascular bundle organization in maize leaf 11. 3D organization of Vascular bundles in maize leaf 12. Xylem anatomical characteristics Safety: Regulation of -Axial flow dynamics by perforation plates -Radial flow dynamics by pit membranes & network connexionBasis of embolism, cavitation mechanismEnvironmental effects: transpiration, osm ostic stress Safety feature of perforation plates, lateral pits: air bubbles appearance/re moval, direct radial inflow of water Network Efficiency: -Effect of enhanced transpiration -Long distance water transport systemIn planta sap flow tracking Protoxylem (PX)Metaxylem (MX)Use of various type of particles to investigate xylem cell wall properties (interactions of AuNPs with cell walls) 13. Flow dynamics in dicot plants (Arabidopsis) of dicot xylem structure Arabidopsis as model Experimental method: -Synchrotron X-ray CT [Xylem network 3D organization]-Hydrophilic AuNP solution [Indicator of sap flow rate] AuNP-OHXylem SCWHOCH2CH2CH2CH2OHDifference of xylem vessel activity monitored by AuNP staining profile 13 14. Pattern of xylem vessel activity in normal condition Normal uptake profile (transpiration driven)Pattern of xylem vessel activity generated by external pressure Artificial uptake profile (external pressure driven) 15. Visualization of water transport pathways Hydrophilic gold-nanoparticles (AuNP) : tracers of axial & radial water flow pathways cInterestingly, all metaxylem vessels do not show the same level of activity for water transport 17 16. Regulation of water transport along plant heightDifferences in vascular bundle organization and pressure gradient directly impact AuNPs staining profile along the height of the inflorescence stem18 17. Water flow pathway in the whole plant scaleEfficient and safe water flow may coexist with one system as division into long-distance and local distribution 19 18. Visualization of chloroplast movement using two-photon microscopyTwo-photon microscopy Tube lensScan lensTi:Sapphire laserDichroic mirror DM1 Tube Scan lens lens Dichroic mirror DM2Galvanometer scannerPMTPiezo stageFilter Objective lensComputer Translation stage 19. Monitoring of chloroplast movement depending on light SSS MBSS SS 20. Summary Place of plants in Environmental & Energy Sciences Importance of understanding Plant-Water relation Synchrotron X-ray imaging method is a powerful tool to study plant vascular structure and sap flow dynamics -Monocot and dicot plants 3D xylem structure (Wiring diagram of plant microfluidic system) -Demand-driven flow system -Efficiency and safety of water transport Perspectives of High-resolution phenotyping -Nano-CT of xylem -Optical Coherance tomography -Two-photon microscopy (photosynthesis) 21. Acknowledgements Advanced Biomass R&D Center Prof. Sang Joon Lee (Department of Mechanical Engineering, POSTECH)Prof. Il Doo Hwang (Department of Life Sciences, POSTECH)Dr. Sung Sook AhnJoong Hyuk ParkJeong Eun RyuSynchrotron facilitiesPAL, PohangSSRF, ShanghaiPF, Tsukuba