Dormancy, cold hardiness and height growth were examined in four poplar clones exposed to four temperature conditions (13.5ºC/8.5ºC, 18.5ºC/3.5ºC, 18.5ºC/13.5ºC and 23.5ºC/8.5ºC day/night temperatures) under short photoperiod. The selected clones were WP-69 (Okanese)- early acclimation, Walker and Katepwa - intermediate acclimation, and Prairie Sky- late acclimation. Changes in physical water properties and mobility within the vascular tissue region, vascular transition region into the axillary bud and the upper axillary bud were assessed during endodormancy development using Magnetic Resonance Microimaging (MRMI). <p>In summary:<br>a) There were distinct differences between poplar clones during dormancy induction in response to temperature. For example, Katepwa, Walker and WP-69 clones became endodormant but Prairie Sky did not enter endodormancy. Endodormancy development and cold acclimation in WP-69 were less affected by temperature than Katepwa and Walker suggesting that genotypic variation exists in response to temperature change.<p>b) Growth cessation, not endodormancy, was a prerequisite for cold acclimation since cold hardiness increased in Prairie Sky in the absence of endodormancy. However, increases in endodormancy coincided with increase in cold hardiness in other clones.<p>c) Low night temperatures (18.5ºC/3.5ºC) delayed endodormancy development and cold acclimation in all clones compared to the warm night temperature treatment (18.5ºC /13.5ºC). Night temperature was negatively correlated with time to growth cessation, and cold hardiness and positively correlated with dormancy development. Changes in night temperature may affect time to growth cessation, subsequently altering timing of cold acclimation and endodormancy development since growth cessation appeared to be a prerequisite for both processes. <p>d) ADC (Apparent Diffusion Coefficient), an indicator of water mobility within living tissues, was negatively correlated with endodormancy induction. Specifically, the transition region of vascular tissue between the stem and the lower axillary bud showed the highest correlation with endodormancy development. By contrast, decreases in T1 relaxation times, an indicator of biophysical water properties, were inconsistent with changes in endodormancy levels in axillary buds. Thus, ADC appears to correspond more closely with endodormancy development than changes in T1 relaxation times. <p>It is apparent that temperature impacts dormancy development in hybrid poplar. Underlying changes in water appear to correspond with changes in endodormancy. Under future warming scenarios, genotypes such as WP 69 (Okanese) that are less sensitive to temperature and maintain a consistent, endodormancy induction pattern, may be better fit to changing climates.

Dormancy, cold hardiness and height growth were examined in four poplar clones exposed to four temperature conditions (13.5ºC/8.5ºC, 18.5ºC/3.5ºC, 18.5ºC/13.5ºC and 23.5ºC/8.5ºC day/night temperatures) under short photoperiod. The selected clones were WP-69 (Okanese)- early acclimation, Walker and Katepwa - intermediate acclimation, and Prairie Sky- late acclimation. Changes in physical water properties and mobility within the vascular tissue region, vascular transition region into the axillary bud and the upper axillary bud were assessed during endodormancy development using Magnetic Resonance Microimaging (MRMI). <p>In summary:<br>a) There were distinct differences between poplar clones during dormancy induction in response to temperature. For example, Katepwa, Walker and WP-69 clones became endodormant but Prairie Sky did not enter endodormancy. Endodormancy development and cold acclimation in WP-69 were less affected by temperature than Katepwa and Walker suggesting that genotypic variation exists in response to temperature change.<p>b) Growth cessation, not endodormancy, was a prerequisite for cold acclimation since cold hardiness increased in Prairie Sky in the absence of endodormancy. However, increases in endodormancy coincided with increase in cold hardiness in other clones.<p>c) Low night temperatures (18.5ºC/3.5ºC) delayed endodormancy development and cold acclimation in all clones compared to the warm night temperature treatment (18.5ºC /13.5ºC). Night temperature was negatively correlated with time to growth cessation, and cold hardiness and positively correlated with dormancy development. Changes in night temperature may affect time to growth cessation, subsequently altering timing of cold acclimation and endodormancy development since growth cessation appeared to be a prerequisite for both processes. <p>d) ADC (Apparent Diffusion Coefficient), an indicator of water mobility within living tissues, was negatively correlated with endodormancy induction. Specifically, the transition region of vascular tissue between the stem and the lower axillary bud showed the highest correlation with endodormancy development. By contrast, decreases in T1 relaxation times, an indicator of biophysical water properties, were inconsistent with changes in endodormancy levels in axillary buds. Thus, ADC appears to correspond more closely with endodormancy development than changes in T1 relaxation times. <p>It is apparent that temperature impacts dormancy development in hybrid poplar. Underlying changes in water appear to correspond with changes in endodormancy. Under future warming scenarios, genotypes such as WP 69 (Okanese) that are less sensitive to temperature and maintain a consistent, endodormancy induction pattern, may be better fit to changing climates.

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Diffusion is an omnipresent, most fundamental phenomenon in nature and thus critical for the performance of numerous technologies. This is in particular true for nanoporous materials with manifold applications for matter upgrading by separation, purification and conversion. The path lengths of molecular transportation within the industrial plants range from the elementary steps of diffusion within the micropores of the individual particles up to the matter flow over macroscopic distances. Each of them might be decisive in determining overall performance so that detailed knowledge of all modes of mass transfer is crucial for a knowledge-based optimization of the devices with reference to their transport properties. The rate of mass transfer is particularly complicated to be assessed within the individual (adsorbent) particles/crystallites with pore sizes of the order of molecular dimensions. We are going to present two powerful techniques exactly for this application, operating under both equilibrium (Pulsed Field Gradient (PFG) NMR) and non-equilibrium (Microimaging by interference microscopy and IR microscopy) conditions. The potentials of these techniques are demonstrated in a few showcases, notably including the options of transport enhancement in pore hierarchies. The contribution concludes with a survey on present activities within an IUPAC initiative aiming at the elaboration of “guidelines for measurements and reporting of diffusion properties of chemical compounds in nanoporous materials”.

This cumulative dissertation is a compilation of eight peer-reviewed, published scientific papers on the subject of two microscopic techniques of diffusion measurement, namely infrared (IR) microimaging and pulsed field gradient (PFG) NMR. The dissertation contains mainly five chapters. The first chapter introduces diffusion phenomena in general and concisely explains the importance and the current challenges of the investigation of molecular diffusion in nanoporous materials, which are the primary motivations behind the present work. To rise the challenges, it proposes an option of employing IR microimaging in parallel with PFG NMR in the measurement of the molecular diffusion. The second chapter describes the basic principles of the two diffusion measurement techniques and what they are capable of. Chapters 3 and 4 deliver convincing demonstrations of their applicability and potential in diffusion studies. Lastly, Chapter 5 concludes the present work by discussing complementary benefits of the two techniques, along with the novel application of the two-region model for assessing mass transfer in hierarchically porous materials.:Table of Contents CHAPTER 1. Introduction CHAPTER 2. Basics of diffusion measurement techniques 2.1. Introduction to infrared microscopy (IRM) 2.1.1. Working principle 2.1.2. Experimental setup 2.2. Introduction to pulsed field gradient nuclear magnetic resonance (PFG NMR) 2.2.1. Self-diffusion and propagator 2.2.2. Theory of PFG NMR CHAPTER 3. Applicability and potential of IRM • Publication 3.1. Anomaly in the chain length dependence of n-alkane diffusion in ZIF 4 metal-organic frameworks • Publication 3.2. Metal-organic framework Co-MOF-74-based host-guest composites for resistive gas sensing • Publication 3.3. Revealing the transient concentration of CO2 in a mixed-matrix membrane by IR microimaging and molecular modeling • Publication 3.4. IR microimaging of direction-dependent uptake in MFI-type crystals CHAPTER 4. Importance of PFG NMR in diffusion studies • Publication 4.1. NMR diffusometry with guest molecules in nanoporous materials • Publication 4.2. Structural characterisation of hierarchically porous silica monolith by NMR cryo-porometry and -diffusometry CHAPTER 5. Complementary benefits of IR microimaging and PFG NMR • Publication 5.1. Diffusion in nanopores: correlating experimental findings with 'first-principles' predictions • Publication 5.2. Diffusion analysis in pore hierarchies by the two-region model Bibliography Appendix A. Supporting information Appendix B. Author contributions