Development of a network of genetic reserves for wild celery in Germany (GE-Sell)

Die Technik des genetischen Erhaltungsgebiets ist ein anwendungsbereites Verfahren zur In-situ-Erhaltung von wildlebenden Verwandten unserer Kulturpflanzen. Bei dem Verfahren wird die dynamische Erhaltung von Populationen, die in ihren natürlichen Lebensräumen Evolutionsprozessen ausgesetzt sind, mit der statischen Erhaltung pflanzengenetischer Ressourcen in Genbanken kombiniert und somit die nachhaltige Nutzung dieser Arten ermöglicht. Im Modell- und Demonstrationsvorhaben "Genetische Erhaltungsgebiete für Wildselleriearten (Apium und Helosciadium) als Bestandteil eines Netzwerks genetischer Erhaltungsgebiete in Deutschland" (GESell) wurden wissenschaftliche und organisatorische Fragestellungen zur Umsetzung dieser Technik bearbeitet. Ziel des Projekts war die modellhafte Einrichtung von 45 genetischen Erhaltungsgebieten (GenEG) für Wildselleriearten und der Aufbau eines bundesweiten Netzwerks aus lokalen Akteuren. Zur Identifizierung der GenEG wurde das monografische Verfahren angewendet. Für die vier in Deutschland vorkommenden Wildselleriearten wurden zum Projektstart im Jahr 2015 aus 2400 Fundortdaten 322 Standorte für Präsenzkontrollen ausgewählt. Im Anschluss wurden für rund 100 möglichst vitale und ungefährdete Vorkommen, die sich über verschiedene Naturräume und Habitate verteilen, genetische Diversitätsanalysen durchgeführt. Anhand der Kartierungs- und Analyseergebnisse wählte das Projektteam zwischen 11 und 15 Vorkommen pro Art aus, die insgesamt die innerartliche Vielfalt der jeweiligen Arten bestmöglich repräsentieren. Für diese Vorkommen wurden die Einrichtung und ein langfristiges Management der GenEG in Zusammenarbeit mit lokalen Akteuren angestrebt. Bis zum April 2020 wurden bereits 15 GenEG eingerichtet.The genetic reserve conservation technique is a ready-to-use procedure for in situ conservation of crop wild relatives. The approach combines the dynamic conservation of populations exposed to evolutionary processes in their natural habitats with the static conservation of plant genetic resources in gene banks, thus enabling the sustainable use of these species. In the model and demonstration project "Genetic reserves for wild celery species (Apium and Helosciadium) as part of a network of genetic reserves in Germany" (GE-Sell) scientific and organisational aspects of the implementation of genetic reserves were investigated. The aim of the project was the establishment of 45 genetic reserves for wild celery species and the establishment of a nationwide network of local stakeholders. The monographic approach was used to identify the genetic reserves. For the four wild celery species occurring in Germany, around 350 occurrences were selected from 2400 known sites for the verification of these occurrences at the project start in 2015. Thereafter, genetic diversity analyses were carried out for approximately 100 occurrences that are as vital as possible, non-endangered and distributed over various ecogeographic regions and habitat types. Based on the survey and analysis results, the project team selected between 11 and 15 occurrences per species, which together represent the intra-species diversity of the respective species best. For these occurrences, the project team aimed at the establishment and long-term management of the genetic reserves in cooperation with local stakeholders. By April 2020, 15 genetic reserves had already been established

Crystal Size Dependent Flexibility in ZIF-7: From Macro- to Nano-Scale

Flexible metal-organic frameworks (MOFs) are highly desirable materials for gas separation but most of them become rigid when the particle size is reduced towards nanoscale. We aim to comprehend the effect of textural properties such as crystal size, its distribution and morphology on the gate-opening behaviour stimulated by adsorption of guest molecules in ZIF-7. The synthesis conditions are varied to obtain ZIF-7 batches with crystal sizes ranging between 0.05 and 15 m with various size distributions. We report for the first time a CO2-filled open pore phase of ZIF-7 at 195 K (OP2) derived from in situ powder X-ray diffraction (PXRD) data measured in parallel to CO2 physisorption. The adsorption of CO2 on ZIF-7 indicates persisting flexibility for all particle size regimes; with the crystal size, its distribution and morphology having a significant impact on both gate-opening and gate-closing pressures and slope of CO2 adsorption isotherms. In situ PXRD measurement indicated further expansion of ZIF-7 framework in presence of methanol as guest species. The capability of ZIF-7 to accommodate molecules larger than its 0.3 nm window diameter signifies the importance of intermolecular interactions to overcome the energy barrier for linker movement/gating of the framework

The importance of crystal size for breathing kinetics in MIL-53(Al)

Herein we analyze the switching kinetics of a breathing framework MIL-53(Al) with respect to different crystallite size regimes. Synchrotron time-resolved powder X-ray diffraction (PXRD) and adsorption rate analysis of n-butane physisorption at 298 K demonstrate the decisive role of crystal size affecting the time domain of breathing transitions in MIL-53(Al)

Spatiotemporal Design of the Metal-Organic Framework DUT-8(M)

Switchable metal-organic frameworks change their structure in time and selectively open their pores adsorbing guest molecules, leading to highly selective separation, pressure amplification, sensing and actuation applications. The three-dimensional engineering of metal-organic frameworks has reached a high level of maturity, but spatiotemporal evolution opens a new perspective towards engineering materials in the 4th dimension (time) by t-axis design, in essence exploiting the deliberate tuning of activation barriers. This work demonstrates the first example in which an explicit temporal engineering of a switchable metal-organic framework (DUT-8, M1M2(ndc)2dabco, ndc = 2,6,-naphthalenedicarboxylate, dabco = 1,4 diazabicyclo[2.2.2]octane, M1 = Ni, M2 = Co) is presented. The temporal response is deliberately tuned by variation of cobalt content. We present a spectrum of advanced analytical methods for analyzing the switching kinetics stimulated by vapor adsorption using in situ time resolved techniques ranging from ensemble adsorption and advanced synchrotron X-ray diffraction experiments to individual crystal analysis. A novel analysis technique based on microscopic observation of individual crystals in a microfluidic channel reveals the lowest limit for adsorption switching reported so far. The time constants for the bulk ensembles range from 2 - 300 s. Differences in spatiotemporal response of crystal ensembles originate from a delay (induction) time that varies statistically and widens characteristically with increasing cobalt content reflecting increasing activation barriers

Spatiotemporal Design of the Metal-Organic Framework DUT-8(M)

Switchable metal-organic frameworks change their structure in time and selectively open their pores adsorbing guest molecules, leading to highly selective separation, pressure amplification, sensing and actuation applications. The three-dimensional engineering of metal-organic frameworks has reached a high level of maturity, but spatiotemporal evolution opens a new perspective towards engineering materials in the 4th dimension (time) by t-axis design, in essence exploiting the deliberate tuning of activation barriers. This work demonstrates the first example in which an explicit temporal engineering of a switchable metal-organic framework (DUT-8, M1M2(ndc)2dabco, ndc = 2,6,-naphthalenedicarboxylate, dabco = 1,4 diazabicyclo[2.2.2]octane, M1 = Ni, M2 = Co) is presented. The temporal response is deliberately tuned by variation of cobalt content. We present a spectrum of advanced analytical methods for analyzing the switching kinetics stimulated by vapor adsorption using in situ time resolved techniques ranging from ensemble adsorption and advanced synchrotron X-ray diffraction experiments to individual crystal analysis. A novel analysis technique based on microscopic observation of individual crystals in a microfluidic channel reveals the lowest limit for adsorption switching reported so far. The time constants for the bulk ensembles range from 2 - 300 s. Differences in spatiotemporal response of crystal ensembles originate from a delay (induction) time that varies statistically and widens characteristically with increasing cobalt content reflecting increasing activation barriers