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Wer in der letzten Zeit einen Spaziergang durch Feld und Flur unternommen hat, dem können Ecken und Streifen aufgefallen sein, die wild und ungepflegt wirken. Was vielleicht nicht so schön aussieht, hat jedoch Sinn: Nicht gemähte oder beweidete stellen bieten Schutz und Nahrung für viele Kleintiere. Damit leisten sie einen wertvollen Beitrag zur Sicherung der Artenvielfalt und Biodiversität. Der Flyer informiert besonders Flächeneigentümer und Bewirtschafter über den Wert von nicht genutzten Grünlandbereichen für die Biodiversität und die Fördermöglichkeiten über die Richtlinie Agrarumwelt- und Klimamaßnahmen (FRL AUK/2023) und die Öko-Regelung. Redaktionsschluss: 13.03.2024

Die Schriftenreihe informiert über die Entwicklung eines CMOS-Sensors mit OLED-Mikrodisplay für die Düngungsoptimierung bei Zierpflanzen. Die Grundannahme, dass sich der Ernährungszustand einer Pflanze in einem hochaufgelösten Bild bzw. Scan ihrer Blätter mit unterschiedlichen Lichtfarben frühzeitig erkennen lässt, konnte weder bestätigt noch widerlegt werden. Es wurden Grundlagen für weitere Forschungsarbeiten gelegt. Die Veröffentlichung richtet sich an Praktiker, Bildung, Forschung & Entwicklung. Redaktionsschluss: 21.11.2023

Die nachhaltige Sicherung der Biodiversität im Wald gehört zum Selbstverständnis von Sachsenforst und wird im Rahmen der integrativen naturgemäßen Waldbewirtschaftung im Landeswald weiter verstetigt. Um dieses Ziel zu erreichen, ist die Etablierung eines aktiven Biotopbaum- und Totholzmanagements im Landeswald erforderlich. Redaktionsschluss: 08.02.2024

Der Evolutionsökologe Niek Scheepens untersucht, wie sich Pflanzen an den Klimawandel anpassen. Dafür holt er Samen aus Saatgutbanken, die dort vor Jahrzehnten eingelagert wurden, und vergleicht Merkmale der daraus wachsenden Pflanzen.

Die Ambrosia ist eine Pflanze mit hochallergenen Pollen. Bedingt durch den Klimawandel breitet sie sich seit wenigen Jahrzehnten auch bei uns aus. Dies muss unbedingt verhindert oder zumindest eingeschränkt werden. Dieses Faltblatt soll über die Merkmale, das Vorkommen, die Verwechslungsmöglichkeiten und besonders über die von der Pflanze ausgehenden Gesundheitsgefahren informieren. Außerdem wird darin auf die Möglichkeiten hingewiesen, wie die Pflanze bekämpft bzw. wie die weitere Verbreitung der Pflanze vermieden werden kann. Redaktionsschluss: 15.08.2023

Für einen kleinflächigen und schrittweisen Waldumbau gibt es viele Ansatzpunkte. Auch kleinere Maßnahmen bringen Vielfalt in den Wald und erhöhen dadurch schrittweise die Stabilität. In der Broschüre möchten wir dazu einige Möglichkeiten skizzieren und das Interesse für einen stetigen Waldumbau wecken. Redaktionsschluss: 20.02.2023

Moose sind wichtige Bioindikatoren, die besonders empfindlich auf Umwelteinflüsse reagieren und Veränderungen in Ökosystemen frühzeitig anzeigen. Rote Listen dokumentieren den Kenntnisstand über die Gefährdung der einzelnen Arten und über den Anteil gefährdeter Arten der betrachteten Sippe. Die Artenliste gibt den aktuellen Stand der floristischen Bearbeitung der Moose wider. Von den aus Sachsen bekannten und bewerteten 807 Moossippen mussten insgesamt 392 einer Gefährdungskategorie zugeordnet werden, das entspricht einem Anteil von 48,5 %. Bezogen auf ausgewählte ökologische Gruppen werden in der vorliegenden Broschüre detaillierte Einschätzungen der Gefährdungssituation gegeben. Redaktionsschluss: 01.09.2023

Crop varieties differing in architectural characteristics (AC) vary in their intra-canopy light distribution. To optimize canopy photosynthesis, we hypothesize that varieties with contrasting AC possess different photosynthetic acclimation strategy (PAS) with respect to photosynthetic nitrogen (Np) partitioning. We firstly used in silico experiments to test this hypothesis and suggested a trade-off in Np partitioning between carboxylation and light harvesting to achieve optimal coordination between PAS, AC and growing light environment. Then, two cucumber (Cucumis sativus L.) cultivars, Aramon and SC-50, which were bred under greenhouse vertical single-stem and field creeping multi-branch canopy, were selected for studying their differences in AC and PAS using greenhouse and growth chamber experiments, respectively. In the greenhouse, more horizontal leaves of SC-50 resulted in steeper intra-canopy light gradient and a higher degree of self-shading, especially in the upper canopy layer. In growth chamber experiments, Aramon invested more leaf nitrogen into photosynthesis than SC-50, and the proportion (pNp) increased as light was reduced. In contrast, pNp of SC-50 did not respond to light but SC-50 partitioned its limited Np between carboxylation and light harvesting functions more effectively, showing a strategy particularly advantageous for canopies with a high degree of self-shading. This is further confirmed by additional in silico experiments showing that Np partitioning of SC-50 coped better with the impact of strong light competition caused by low light and by leaf clumping under high planting density. These findings provide a comprehensive perspective of genotypic variation in PAS, canopy architectures and their optimal coordination., Peer Reviewed

The biosynthesis of the tetrapyrrole end-products chlorophyll and heme depends on a multifaceted control mechanism that acts primarily at the post-translational level upon the rate-limiting step of 5-aminolevulinic acid synthesis and upon light-dependent protochlorophyllide oxidoreductase (POR). These regulatory processes require auxiliary factors that modulate the activity, stability, complex formation, and subplastidal localization of the relevant proteins. Together, they ensure optimal metabolic flow during the day and at night. As an Arabidopsis homolog of the POR-interacting tetratricopeptide-repeat protein (Pitt) first reported in Synechocystis, we characterize tetrapyrrole biosynthesis-regulating tetratricopeptide-repeat protein1 (TTP1). TTP1 is a plastid-localized, membrane-bound factor that interacts with POR, the Mg protoporphyrin monomethylester cyclase CHL27, glutamyl-tRNA reductase (GluTR), GluTR-binding protein, and FLUORESCENCE IN BLUE LIGHT. Lack of TTP1 leads to accumulation of GluTR, enhanced 5-aminolevulinic acid synthesis and lower levels of POR. Knockout mutants show enhanced sensitivity to reactive oxygen species and a slower greening of etiolated seedlings. Based on our studies, the interaction of TTP1 with GluTR and POR does not directly inhibit their enzymatic activity and contribute to the control of 5-aminolevulinic acid synthesis. Instead, we propose that TTP1 sequesters a fraction of these proteins on the thylakoid membrane, and contributes to their stability., Peer Reviewed

To adapt to climate change, several agricultural strategies are currently being explored, including a shift in land use areas. Regional differences in microbiome composition and associated phytopathogens need to be considered. However, most empirical studies on differences in the crop microbiome focused on soil communities, with insufficient attention to the phyllosphere. In this study, we focused on wheat ears in three regions in northeastern Germany (Magdeburger Börde (MBB), Müncheberger Sander (MSA), Uckermärkisches Hügelland (UKH)) with different yield potentials, soil, and climatic conditions. To gain insight into the fungal community at different sites, we used a metabarcoding approach (ITS-NGS). Further, we examined the diversity and abundance of Fusarium and Alternaria using culture-dependent and culture-independent techniques. For each region, the prevalence of different orders rich in phytopathogenic fungi was determined: Sporidiobolales in MBB, Capnodiales and Pleosporales in MSA, and Hypocreales in UKH were identified as taxonomic biomarkers. Additionally, F. graminearum was found predominantly in UKH, whereas F. poae was more abundant in the other two regions. Environmental filters seem to be strong drivers of these differences, but we also discuss the possible effects of dispersal and interaction filters. Our results can guide shifting cultivation regions to be selected in the future concerning their phytopathogenic infection potential., Deutsche Forschungsgemeinschaft, Peer Reviewed

This article was supported by the German Research Foundation (DFG) and the Open Access Publication Fund of Humboldt-Universität zu Berlin., After entry of a quarantine/regulated pathogen, infected plants shall be destroyed, and the cultivated area (e.g., greenhouse) shall be disinfected. Therefore, the selection of an effective disinfectant plays an important role. With the availability of different methods for virus quantification, we investigated the application of quantitative ELISA (qELISA), RT-qPCR (reverse transcription-quantitative polymerase chain reaction), and bioassays for the quantification of disinfectant efficacy. Therefore, we estimated the titer reduction in tomato brown rugose fruit virus (ToBRFV), a regulated pathogen, in plant sap and on germ carriers after treatment with MENNO Florades 4% for 16 h. The virus load before and after the treatment was measured with the mentioned methods. The RT-qPCR and qELISA methods showed very low efficacy in the presence of the disinfectant. Although bioassays are time-consuming, need purified particles for establishing the quantification models, and are less sensitive than RT-qPCR, they were able to quantify the differences in virus titer in the presence/absence of disinfectant. Interestingly, the bioassays reached at least the lower limit sensitivity of a qELISA. By being less sensitive to the presence of the disinfectant, bioassays proved to be the only technique for the determination of the disinfectant efficacy against ToBRFV on different germ carriers as well as on virus-infected plant sap., Menno Chemie-Vertriebs GmbH, Agro-Horti Testlabor, Deutsche Forschungsgemeinschaft, Open Access Publication Fund of Humboldt-Universität zu Berlin, Peer Reviewed

Oft gehen wir im Wald spazieren, genießen das Grün der Bäume und Sträucher. Dabei übersehen wir aber leicht, dass es am Boden zahlreiche Gräser und Kräuter gibt. Sie erfüllen eine wichtige ökologische Funktion für viele andere Lebewesen, besonders für Insekten. Es lohnt sich, diese Arten kennenzulernen. Dazu soll diese handliche Bestimmungshilfe beitragen. Wesentliche Informationen zur Bestimmung ausgewählter Pflanzen des Waldes und seiner Saumbereiche sind in kompakter Form dargestellt. Detaillierte Zeichnungen illustrieren die wichtigsten Merkmale. Eine gezeichnete Hummel symbolisiert die Bedeutung der jeweiligen Art für Insekten. Redaktionsschluss: 23.02.2023

Ziel der vorliegenden Forschungsarbeit ist es, eine Übersicht der Pflanzengesellschaften Sachsens vorzulegen. Dabei wird zunächst ein grundsätzliches syntaxonomisches Konzept zur Bearbeitung der Vegetation Sachsens vorgestellt. Inhalt des vorliegenden ersten Heftes ist die Klasse der Molinio-Arrhenatheretea (Kulturgrasland aus Fettwiesen und Fettweiden, jedoch ohne Kriech- und Flutrasen). Die Pflanzengesellschaften werden durch Referenztabellen und Texte in ihrer Vielfalt mit wichtigen regionalen und standörtlichen Ausprägungen in prägnanter Weise beschrieben. Grundlage sind ca. 3000 syntaxonomisch bearbeitete Vegetationsaufnahmen. Die Übersicht ist so strukturiert, dass sie sowohl mit der - bislang ausschließlich in Textform vorliegenden - Rote Liste der Pflanzengesellschaften Sachsens (BÖHNERT et al. 2021) als auch mit dem sächsischen Kartier- und Bewertungsschlüssel für FFH-Lebensraumtypen (LFULG 2009), dessen Erfassungskriterien wesentlich auf der Zuordnung zu Pflanzengesellschaften beruhen, verglichen werden kann. Bei der Formulierung der deutschen Namen der Syntaxa wurden die Vorschläge von KORNECK (1984) berücksichtigt, die auf den Ebenen von Assoziationen und Verbänden zu Veränderungen gegenüber BÖHNERT et al. (2021) führten. Die Übersicht soll den Kartierern des Langzeitmonitoring der FFH-Lebensraumtypen in Sachsen als informative Handreichung zum Kartier- und Bewertungsschlüssel zur Verfügung gestellt werden. Darüber hinaus wird ein breiter Nutzerkreis im Bereich Biologie und Naturschutz angesprochen., The aim of the present research work is to present an overview of the plant communities in Saxony. Therefor a basic syntaxonomic concept for processing the vegetation of Saxony is presented. This issue also presents a reviewed classification of Molinio-Arrhenatheretea (without flood and creeping swards). The plant communities are described by reference tables and texts to show their diversity and important regional and local characteristics. The work is based on more than 3000 syntaxonomic relevés. The classification allows a comparison with the Red List of Plant Communities in Saxony (BÖHNERT et al. 2021) and with the Saxon mapping and assessment key for FFH habitat types (LfULG 2009). The results support the recognition and mapping of FFH-habitats. The publication adresses a wide range of users in the field of biology and nature conservation.

During photoperiodic growth, the light-dependent nature of chlorophyll synthesis in angiosperms necessitates robust control of the production of 5-aminolevulinic acid (ALA), the rate-limiting step in the initial stage of tetrapyrrole biosynthesis (TBS). We are interested in dissecting the post-translational control of this process, which suppresses ALA synthesis for chlorophyll synthesis in dark-grown plants. Using biochemical approaches for analysis of Arabidopsis wild-type (WT) and mutant lines as well as complementation lines, we show that the heme-synthesizing ferrochelatase 2 (FC2) interacts with protochlorophyllide oxidoreductase and the regulator FLU which both promote the feedback-controlled suppression of ALA synthesis by inactivation of glutamyl-tRNA reductase, thus preventing excessive accumulation of potentially deleterious tetrapyrrole intermediates. Thereby, FC2 stabilizes POR by physical interaction. When the interaction between FC2 and POR is perturbed, suppression of ALA synthesis is attenuated and photoreactive protochlorophyllide accumulates. FC2 is anchored in the thylakoid membrane via its membrane-spanning CAB (chlorophyll-a-binding) domain. FC2 is one of the two isoforms of ferrochelatase catalyzing the last step of heme synthesis. Although FC2 belongs to the heme-synthesizing branch of TBS, its interaction with POR potentiates the effects of the GluTR-inactivation complex on the chlorophyll-synthesizing branch and ensures reciprocal control of chlorophyll and heme synthesis., Chinese Scholarship Council, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Peer Reviewed

GATAs are evolutionarily conserved zinc-finger transcription factors from eukaryotes. In plants, GATAs can be subdivided into four classes, A–D, based on their DNA-binding domain, and into further subclasses based on additional protein motifs. B-GATAs with a so-called leucine-leucine-methionine (LLM)-domain can already be found in algae. In angiosperms, the B-GATA family is expanded and can be subdivided in to LLM- or HAN-domain B-GATAs. Both, the LLM- and the HAN-domain are conserved domains of unknown biochemical function. Interestingly, the B-GATA family in the liverwort Marchantia polymorpha and the moss Physcomitrium patens is restricted to one and four family members, respectively. And, in contrast to vascular plants, the bryophyte B-GATAs contain a HAN- as well as an LLM-domain. Here, we characterise mutants of the single B-GATA from Marchantia polymorpha. We reveal that this mutant has defects in thallus growth and in gemma formation. Transcriptomic studies uncover that the B-GATA mutant displays a constitutive high-light (HL) stress response, a phenotype that we then also confirm in mutants of Arabidopsis thaliana LLM-domain B-GATAs, suggesting that the B-GATAs have a protective role towards HL stress., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Peer Reviewed

The article processing charge was funded by the Open Access Publication Fund of Humboldt-Universität zu Berlin., South American grasslands contain extraordinary biodiversity and play a central role in the subsistence of regional agroecosystems. In recent decades, afforestation, followed by the soybean planting boom, have led to drastic land‐use changes at the expense of grasslands. Impacts on local biodiversity have remained understudied. We explored the taxonomic richness and ß‐diversity of plants of ground layer (excluding trees and shrubs) at different land uses, its interplay at regional scale with environmental heterogeneity, and at local scale with novel land cover types and landscape configurations. We conducted correlation, principal component, NDMS, and SDR analysis to explore variation of taxonomic richness, richness difference, replacement, and similarity of ground flora as response to environmental filters and land use change across Uruguay. We surveyed 160 plots distributed in 10 land cover types, that is, closed and open native forests, different grasslands, crops, orchards, and timber plantations. We observed overlaying regional patterns driven by seasonality of temperature and precipitation, and land cover shaping taxonomic richness at local scale. Landscape configuration affects diversity patterns of native ground flora, which seems to be sustained mainly by the “old growth grassland” species pool. Taxonomic richness of native species decreases with an increase of distance to grassland. Crops and grasslands harbor a higher number of native species in the ground flora than native forests and timber plantations. The introduction of exotics is driven mostly by crops or highly modified pastures. Diversity patterns only partially reflect the ecoregion concept. Expanding the perspective from conservation in purely natural ecosystems to measures conserving species richness in human‐modified landscapes is a powerful tool against species loss in the Anthropocene., Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347, Peer Reviewed

Protochlorophyllide oxidoreductase (POR), which converts protochlorophyllide into chlorophyllide, is the only light-dependent enzyme in chlorophyll biosynthesis. While its catalytic reaction and importance for chloroplast development are well understood, little is known about the post-translational control of PORs. Here, we show that cpSRP43 and cpSRP54, two components of the chloroplast signal recognition particle pathway, play distinct roles in optimizing the function of PORB, the predominant POR isoform in Arabidopsis. The chaperone cpSRP43 stabilizes the enzyme and provides appropriate amounts of PORB during leaf greening and heat shock, whereas cpSRP54 enhances its binding to the thylakoid membrane, thereby ensuring adequate levels of metabolic flux in late chlorophyll biosynthesis. Furthermore, cpSRP43 and the DnaJ-like protein CHAPERONE-LIKE PROTEIN of POR1 concurrently act to stabilize PORB. Overall, these findings enhance our understanding of the coordinating role of cpSPR43 and cpSRP54 in the post-translational control of chlorophyll synthesis and assembly of photosynthetic chlorophyll-binding proteins., Chinese Scholarship Council, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Hong Kong Research Grants Council Early Career Scheme, Peer Reviewed

Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery—and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in., Peer Reviewed

Seed dispersal is a key ecosystem function for plant regeneration, as it involves the movement of seeds away from the parental plants to particular habitats where they can germinate and transition to seedlings and ultimately adult plants. Seed dispersal is shaped by a diversity of abiotic and biotic factors, particularly by associations between plants and climate and between plants and other species. Due to the ongoing loss of biodiversity and changing global conditions, such interactions are prone to change and pose a severe threat to plant regeneration. One way to address this challenge is to study associations between plant traits and abiotic and biotic factors to understand the potential impacts of global change on plant regeneration. Plant communities have long been analyzed through the lens of vegetative traits, mainly ignoring how other traits interact and respond to the environment. For instance, while associations between vegetative traits (e.g., specific leaf area, leaf nitrogen content) and climate are well studied, there are few case studies of reproductive traits in relation to trait-environment associations in the context of global change. Thus, the overarching aim of this dissertation is to explore how trait-environment associations, with a special focus on reproductive traits, can improve our understanding of the effect that global change may have on seed dispersal, and ultimately on plant regeneration. To this end, my research focuses on studying associations between plant traits and abiotic and biotic factors along an elevational gradient in both forests and deforested areas of tropical mountains. This dissertation addresses three principal research objectives. First, I investigate the extent to which reproductive (seed and fruit traits) and vegetative traits (leaf traits) are related to abiotic and biotic factors for communities of fleshy-fruited plants in the Ecuadorian Andes. I used multivariate analyses to test associations between four (a)biot, Die Samenausbreitung ist eine essentielle Ökosystemfunktion für die Pflanzenregeneration. Sie wird von einer Vielzahl abiotischer und biotischer Faktoren beeinflusst. Aufgrund des voranschreitenden globalen Wandels sind die Wechselwirkungen zwischen Pflanzen und diesen Umweltfaktoren häufig gestört, wodurch die Pflanzenregeneration eingeschränkt ist. Das übergeordnete Ziel meiner Dissertation ist es daher, die Zusammenhänge zwischen Pflanzenmerkmalen und abiotischen und biotischen Faktoren zu untersuchen, um die potenziellen Auswirkungen des globalen Wandels auf die Samenausbreitung und letztlich auf die Pflanzenregeneration besser zu verstehen. Da Pflanzengemeinschaften lange Zeit vor allem mit einem Fokus auf vegetative Merkmale analysiert wurden, hat meine Dissertation einen besonderen Schwerpunkt auf die reproduktiven Merkmale innerhalb der Pflanzengemeinschaften, welche ich entlang eines Höhengradienten in den ecuadorianischen Anden untersucht habe. Zunächst untersuchte ich, inwieweit reproduktive (Samen- und Fruchtmerkmale) und vegetative Merkmale (Blattmerkmale) in Baumgemeinschaften mit abiotischen und biotischen Faktoren zusammenhängen. Ich habe hierfür reproduktive und vegetative Merkmale von verschiedenen Pflanzenarten gemessen und die Beziehungen zwischen diesen Merkmalen und den Umweltbedingungen mit multivariaten Analysen untersucht. Meine Analysen zeigen, dass die Klima- und Bodenbedingungen stark mit der Verteilung sowohl der reproduktiven als auch der vegetativen Merkmale in tropischen Baumgemeinschaften assoziiert sind. Die Produktion von "teuren" bzw. "günstigen" Samen, Früchten und Blättern, wie z.B. wenige, stickstoffreiche Früchte (hohe Belohnung) versus viele, kohlenstoffreiche Früchte (geringe Belohnung), wird in erster Linie durch die Temperatur begrenzt. Die Größe der Pflanzenorgane hängt hingegen eher mit Veränderungen der Niederschlags- und Bodenbedingungen zusammen. Interessanterweise zeigen meine Analysen, dass Klima und Bodenbedingunge

The lianescent genus Tinospora Miers in Singapore is revised. Four species are recognised, two of which are newly described. Tinospora krispura I.M.Turner sp. nov. is known from Christmas Island and Singapore. Tinospora singapura I.M.Turner sp. nov. is known only from Singapore. Two new lectotypifications are included, one at the second step.

A comprehensive checklist of Habenaria from Chapada dos Veadeiros, State of Goiás, was performed alongside morphologic and molecular phylogenetic studies, revealing three new taxa endemic to this region. A total of 61 taxa (59 species and two varieties) of Habenaria are recorded for Chapada dos Veadeiros, representing a two-fold increase compared to previous lists and comprising one of the greatest diversities of the genus in Brazil. Of this total, four taxa are locally endemic. Habenaria cultellifolia, until recently known only from the type collection, was rediscovered in the region after 127 years without records and represents this species’ only known extant population. Three proposed new taxa of Habenaria (H. minuticalcar J.A.N. Bat. & Bianch. sp. nov., H. proiteana J.A.N. Bat., A.A. Vale & Bianch. sp. nov., and H. lavrensis var. xanthodactyla J.A.N. Bat. & Bianch. var. nov.) are corroborated by molecular phylogenetic analyses based on nuclear and plastid markers. They are described, illustrated, tentatively assessed as threatened, and compared to phylogenetically and morphologically related species. Since some areas of this mountain range have not yet been floristically sampled, additional taxonomic novelties and new records are still expected in the future.

Merianthera is a genus of flowering plants with up to now seven species occurring in eastern Brazil, in the states of Bahia, Espírito Santo, and Minas Gerais. It belongs to the tribe Pyramieae (Melastomataceae), and can be recognized by its shrubby or treelet habit with caducous leaves, 5-merous flowers with a strongly zygomorphic androecium, the latter with dimorphic stamens bearing complex dorsal connective appendages, as well as an inferior ovary and capsular fruits. We describe here a new species of Merianthera from two collections and a photographic record, all from the same locality, an inselberg in the Municipality of Jacinto, in northeastern Minas Gerais. Its candelabriform habit, with a fistulose stem, and solitary, axillary or cauliflorous flowers are only shared with M. burlemarxii. However, M. calyptrata R.Goldenb., Bochorny & Fraga sp. nov. has at least three characters that are absent in M. burlemarxii and all other species in the genus: the total absence of both a peduncle and bracteoles, the calyptrate calyx and the fruits developing from inferior ovaries and dehiscing through longitudinal slits. The first character appears to be unknown in other species in the family.

All land plants encode 2 isoforms of protoporphyrinogen oxidase (PPO). While PPO1 is predominantly expressed in green tissues and its loss is seedling-lethal in Arabidopsis (Arabidopsis thaliana), the effects of PPO2 deficiency have not been investigated in detail. We identified 2 ppo2 T-DNA insertion mutants from publicly available collections, one of which (ppo2-2) is a knock-out mutant. While the loss of PPO2 did not result in any obvious phenotype, substantial changes in PPO activity were measured in etiolated and root tissues. However, ppo1 ppo2 double mutants were embryo-lethal. To shed light on possible functional differences between the 2 isoforms, PPO2 was overexpressed in the ppo1 background. Although the ppo1 phenotype was partially complemented, even strong overexpression of PPO2 was unable to fully compensate for the loss of PPO1. Analysis of subcellular localization revealed that PPO2 is found exclusively in chloroplast envelopes, while PPO1 accumulates in thylakoid membranes. Mitochondrial localization of PPO2 in Arabidopsis was ruled out. Since Arabidopsis PPO2 does not encode a cleavable transit peptide, integration of the protein into the chloroplast envelope must make use of a noncanonical import route. However, when a chloroplast transit peptide was fused to the N-terminus of PPO2, the enzyme was detected predominantly in thylakoid membranes and was able to fully complement ppo1. Thus, the 2 PPO isoforms in Arabidopsis are functionally equivalent but spatially separated. Their distinctive localizations within plastids thus enable the synthesis of discrete subpools of the PPO product protoporphyrin IX, which may serve different cellular needs., Peer Reviewed

Im Rahmen des von der KfW Stiftung geförderten Artenschutzprojektes „Erhaltungskulturen von bedrohten Pflanzen in Hessen“ wurden in den Jahren 2014–2018 von 15 gefährdeten Pflanzenarten in verschiedenen Regionen Hessens Samen gesammelt und im Botanischen Garten der Stadt Frankfurt am Main vermehrt. In Zusammenarbeit mit Naturschutzbehörden, Forstämtern und Naturschutzverbänden wurden dokumentierte Wiederansiedlungsmaßnahmen oder Populationsstärkungen durchgeführt. Überzähliges Saatgut wurde im Botanischen Garten eingefroren und kann für zukünftige Artenschutzprojekte verwendet werden. Bei den 15 gefährdeten Arten handelt es sich um Allium strictum, Festuca albensis, Fumana procumbens, Iris spuria, Jurinea cyanoides, Mibora minima, Moenchia erecta, Nigella arvensis, Poa badensis, Scleranthus verticillatus, Sedum villosum, Spergula pentandra, Ventenata dubia, Veronica acinifolia und Vicia orobus. Alle diese Arten sind als Verantwortungsarten Bestandteil der hessischen Biodiversitätsstrategie. Im Jahr 2021, also drei Jahre nach dem Ende des Projektes, ergab eine Erfolgskontrolle folgendes Ergebnis: Von insgesamt 50 Wiederansiedlungsversuchen an 34 Orten sind immerhin 25 (50 %) erfolgreich. Weitere 5 (10 %) sind möglicherweise ebenfalls gelungen, jedoch sind die neu begründeten Populationen sehr klein. Eindeutig misslungen sind 20 (40 %). Die Gründe für das Misslingen sind meist klar erkennbar und werden thematisiert: Manchmal war der Zielort ungünstig gewählt, oder die verwendete Ansiedlungsmethode erwies sich als ungeeignet. Das Projekt konnte dazu beitragen, unser Wissen über Ökologie und Verbreitung sowie Gefährdung und Schutzbedarf dieser Verantwortungsarten teils erheblich zu vermehren. Damit leistet es auch einen Beitrag zum Schutz der bereits bestehenden Altpopulationen., Within the framework of the species conservation project “Conservation Cultures of Threatened Plants in Hesse” funded by KfW Stiftung, seeds of 15 endangered plant species were collected in different regions of Hesse and propagated in the Botanical Garden of Frankfurt am Main in 2014–2018. Documented reintroductions or population reinforcements were carried out in cooperation with nature conservation authorities, forestry offices and nature conservation associations. Surplus seeds were frozen in the Botanical Garden and can be used for future species conservation projects. The 15 endangered species are Allium strictum, Festuca albensis, Fumana procumbens, Iris spuria, Jurinea cyanoides, Mibora minima, Moenchia erecta, Nigella arvensis, Poa badensis, Scleranthus verticillatus, Sedum villosum, Spergula pentandra, Ventenata dubia, Veronica acinifolia and Vicia orobus. All these are listed as species of responsibility according to the Hessian biodiversity strategy. A success control in 2021, three years after the end of the project, revealed that 25 (50 %) of a total of 50 reintroduction attempts at 34 locations were successful. Additional 5 reintroduction attempts (10 %) may also have been successful, but the newly established populations are very small. 20 (40 %) were not successful. The reasons for such failure are usually clear: In some cases the target site was unfavorable or the establishment method used proved unsuitable. The project was able to contribute to increase our knowledge about ecology and distribution as well as endangerment and need for protection of these species of responsibility, in some cases considerably. Thus, it also contributes to the protection of the already existing populations.

Campanula cervicaria steht in Hessen kurz vor dem Aussterben und wurde im Rahmen des Kooperationsvertrages zwischen der Botanischen Vereinigung für Naturschutz in Hessen (BVNH) und dem Land Hessen untersucht. Das Ziel der Untersuchung war, herauszufinden wo Campanula cervicaria in Hessen noch vorkommt und wie groß die Populationen sind. In Hessen sind aktuell noch 20 Populationen vorhanden. Fast 90 % der Populationen befinden sich in der Umgebung von Lißberg, Hirzenhain und Gedern im Westlichen Unteren Vogelsberg. Zwei weitere liegen bei Jossa im Spessart und bei Ober-Gleen im Nördlichen Vogelsberg-Vorland. Die größte Population befindet sich an der Kreisstraße 216 bei Hirzenhain am Forsthaus Luisenlust. Campanula cervicaria wächst in Hessen an sonnenexponierten Wegböschungen und Windwurfflächen, meist zusammen mit Hypericum hirsutum und Brachypodium sylvaticum. Um auch zukünftig die Bestände von Campanula cervicaria zu sichern, müsste ein Artenhilfskonzept erarbeitet werden., Campanula cervicaria is on the verge of extinction in Hesse and was studied within the framework of the cooperation agreement between the BVNH and the state of Hesse. The aim of the study was to find out where Campanula cervicaria still occurs in Hesse and how large the populations are. Currently, 20 populations are still present in Hesse. Almost 90 % of the populations are located in the vicinity of Lißberg, Hirzenhain and Gedern in the western Lower Vogelsberg. Two others are located near Jossa in the Spessart and near Ober-Gleen in the Northern Vogelsberg foothills. The largest population is found along the district road 216 near Hirzenhain at the forester’s lodge Luisenlust. Campanula cervicaria grows in Hesse on sun-exposed path embankments and windthrow areas, mostly together with Hypericum hirsutum and Brachypodium sylvaticum. In order to secure Campanula cervicaria populations in the future, a species support concept would have to be developed.

In diesem Artikel und weiteren geplanten Folgen werden Ergänzungen, Nachträge, Erläuterungen und Korrekturen sowohl zum von der Taunusflora (Wittig & al. 2022) erfassten Gebiet (Vortaunus, Hoher Taunus, kammnaher Hintertaunus) als auch zum bisher nicht bearbeiteten kammfernen Bereich des Hintertaunus publiziert. Bei den bisherigen Ergänzungen und Nachträgen handelt es sich um die Ergebnisse der Nachbestimmung eines Belegs (Allium christophii), den Fund einer für das Gebiet bisher nicht genannten Art (Hylotelephium vulgare) sowie um Hinweise auf ältere Funde (Bolboschoenus maritimus, Polystichum lonchitis) und einen neueren Fund (Luronium natans). Weiterhin werden die wichtigsten Ergebnisse der Begehungen sechs kammferner Rasterfelder präsentiert (Rote-Liste- und sonstige seltene Arten). Als selten werden diejenigen Arten angesehen, die im bisherigen Kartierungsgebiet in maximal 5 % (= 26) der insgesamt 523 Rasterfelder gefunden wurden. Außerdem werden in der Taunusflora enthaltene Fehler korrigiert., In this one and in a planned series of following articles, the authors (will) present additions, supplements, explanations and corrections both for the area covered by the Taunus flora (Wittig & al. 2022) (Vortaunus, Hoher Taunus, Hintertaunus near the ridge) and for the previously unprocessed area of the Hintertaunus far from the ridge. The recent additions and supplements are the results of the re-determination of a specimen (Allium christophii), the find of a species not previously mentioned for the area (Hylotelephium vulgare) as well as references to older finds (Bolboschoenus maritimus, Polystichum lonchitis) and to a more recent one (Luronium natans). Additionally, the most important results of the inspections of six remote grid fields are presented (red-listed and other rare species). Species are considered rare if they were found in a maximum of 5 % (= 26) of the total of 523 grid fields in the previous mapping area. Furthermore, errors contained in the Taunusflora are corrected.

Im Taunus wurden an Straßen bisher fünf Arten festgestellt, die allgemein als Charakterarten der mitteleuropäischen Salzvegetation gelten und daher als Salzpflanzen im engeren Sinne bezeichnet werden können: Cochlearia danica, Plantago coronopus, Puccinellia distans, Spergularia marina und Trifolium fragiferum. Mit Ausnahme der Vorkommen von Trifolium fragiferum handelt es sich dabei oft um nur wenige weitere Arten enthaltende Dominanzbestände, wobei Trittpflanzen am häufigsten vertreten sind, so dass Straßenrandvegetation mit Puccinellia distans in der vorliegenden Literatur allgemein den Trittpflanzengesellschaften zugeordnet wurde (Plantaginetea majoris beziehungsweise Polygono-Poetea annuae). Entsprechendes gilt auch für viele Vorkommen von Plantago coronopus. Wie die vorliegende Arbeit zeigt, können aber einige der aus dem Taunus vorliegenden Aufnahmen mit Plantago coronopus zu den Salzwiesen im weiteren Sinne gestellt werden (Juncetea maritimi). Entsprechendes gilt für die hier präsentierte Vegetationsaufnahme eines Cochlearia-danica-Bestandes. Trifolium fragiferum wurde dagegen in einer als Flutrasen (Molinio-Arrhenatheretea, Agrostietalia stoloniferae) zu bezeichnenden Pflanzengesellschaft angetroffen., So far, five species have been found at roads in the Taunus, which are generally considered to be characteristic species of Central European salt vegetation and therefore can be described as salt plants in the narrower sense: Cochlearia danica, Plantago coronopus, Puccinellia distans, Spergularia marina and Trifolium fragiferum. With the exception of the stands of Trifolium fragiferum, these communities contain only a few other species, with plants of trampled places being the most common. Therefore, roadside vegetation with Puccinella distans in the available literature has been generally assigned to the communities of trampled sites (Plantaginetea majoris or Polygono-Poetea annuae). However, some of the relévés with Plantago coronopus from the Taunus can be assigned to the class of salt marshes in the broader sense (Juncetea maritimi). The same applies to the relévé of a Cochlearia-danica-stand presented here. Trifolium fragiferum, on the other hand, was found in a plant community that can be described as floodplain vegetation (Molinio- Arrhenatheretea, Agrostietalia stoloniferae).

Betrachtet man die Anzahl der in Hessen ausgestorbenen Pflanzenarten über den gesamten Zeitraum ab Beginn der floristischen Erforschung, so scheint ein Zusammenhang zwischen der geringeren Anzahl ausgestorbener Arten in den letzten Dekaden und den gleichzeitig vermehrt ausgewiesenen Naturschutzgebieten zu bestehen. Es stellt sich daher die Frage, ob es auch einen kausalen Zusammenhang gibt, oder ob andere Faktoren einen Einfluss auf das Ausmaß an ausgestorbenen Pflanzenarten haben. Für die Entwicklung der Aussterberate in den kommenden Jahrzehnten wird es nötig werden, alle Vorkommen der derzeit vom Aussterben bedrohten Pflanzenarten dahingehend zu überprüfen, ob ihr Bestand gesichert und erhalten werden kann. So kann dann die Frage beantwortet werden, ob es gelungen ist, das Aussterben von Pflanzenarten in Hessen zu stoppen oder lediglich zu verlangsamen., Looking at the number of extinct plant species in Hesse over the entire period from the beginning of floristic research, there seems to be a connection between the lower number of extinct plant species in the last decades and the simultaneously increased number of designated nature reserves. The question therefore arises as to whether there is also a causal relationship, or whether other factors have an influence on the extent of extinct plant species. For the development of the extinction rate in the coming decades, it will be necessary to examine all occurrences of plant species currently threatened with extinction to see whether their existence can be secured and maintained. This will then make it possible to answer the question of whether it has been possible to stop or merely slow down the extinction of plant species in Hesse.

Unsere bisherige Kenntnis zur Situation von Crepis praemorsa (Abbiss-Pippau) war ungenügend und wurde im Rahmen eines Kooperationsprojektes mit dem Hessischen Landesamt für Naturschutz, Umwelt und Geologie (HLNUG) erheblich verbessert. Die Untersuchungen zeigen, dass es in Hessen offenbar nur noch acht Vorkommen dieser Art gibt: Drei sehr kleine Reliktpopulationen an der Bergstraße, eine im nordhessischen Bergland und vier in der Rhön, davon zwei sehr kleine. Keine der Populationen kann als groß bezeichnet werden, die Anzahl der Individuen liegt zwischen wenigen Exemplaren bis zum niedrigen dreistelligen Bereich. Lediglich eine Population erscheint aktuell ungefährdet. Fehlende Nutzung oder Pflege und in der Folge Verbrachung und Verbuschung sowie Lichtmangel durch Beschattung sind maßgebliche Gefährdungen. Ohne aktive Hilfsmaßnahmen werden vier dieser acht Populationen in naher Zukunft erlöschen., Our previous knowledge of the situation of Crepis praemorsa was insufficient and has been considerably improved within the framework of a cooperation project with the Hessian State Agency for Nature Conservation, Environment and Geology (HLNUG). The investigations show that there are apparently only eight occurrences of this species left in Hessen: Three very small relict populations on the Bergstrasse, one in the mountainous region of northern Hesse and four in the Rhoen, two of which are very small. None of the populations can be described as large; the number of individuals ranges from a few specimens to the low three-digit range. Only one population appears to be not endangered. Lack of agricultural use or nature conservation maintenance and, as a consequence, scrub encroachment and lack of light due to shading are significant threats. Without active support measures, five of these eight populations will become extinct in the near future.

Funde von Enno Schubert und Thomas Gregor aus dem Weschnitztal (Hessen, Landkreis Bergstraße) werden mitgeteilt., Findings and corrections of Enno Schubert and Thomas Gregor from the vicinity of Weschnitz valley (Hesse, Bergstrasse county) are reported.

Seed harvesting from wild plant populations is key for ecological restoration, but may threaten the persistence of source populations. Consequently, several countries have set guidelines limiting the proportions of harvestable seeds. Here, we use high-resolution data from 298 plant species to model the demographic consequences of seed harvesting. We find that the current guidelines only protect some species, but are insufficient or overly restrictive for others. We show that the maximum possible fraction of seed harvesting is strongly associated with harvesting frequency and generation time of the target species, ranging from 100% in long-lived species to <1% in the most annuals. Our results provide quantitative basis to guide seed harvesting legislation based on species’ generation time and harvesting regime.

Die Genetik hat die Landwirtschaft erheblich vorangebracht, weil sich mit ihrer Hilfe wesentlich ertragreichere Arten züchten lassen. Dabei werden Pflanzen mit vorteilhaften Eigenschaften ausgewählt und mit solchen gekreuzt, die andere erstrebenswerte Merkmale aufweisen. Auf diese Weise erhält man hybride Pflanzensorten, die beispielsweise widerstandsfähiger gegenüber Schädlingen und Krankheiten sind und sich besser an unterschiedliche Umweltbedingungen anpassen können. Aber das reicht nicht mehr, selbst mit den leistungsfähigsten und ertragreichsten Zuchtpflanzen steht die Landwirtschaft vor großen Herausforderungen: Klimawandel, Wasserknappheit und schlechte Bodenqualität begrenzen die Höhe landwirtschaftlicher Erträge, gleichzeitig wächst mit der Weltbevölkerung natürlich auch der Bedarf an Nahrungsmitteln. Wesentliche Fortschritte in der Nahrungsmittelerzeugung sind allerdings zu erwarten, wenn bei der Entwicklung von Nahrung nicht nur genetische, sondern auch epigenetische Verfahren angewandt werden, um Nahrungspflanzen weiterzuentwickeln – Verfahren, die darauf beruhen, einzelne Gene gezielt an- und abzuschalten. Seit einigen Jahren forscht dazu an der Goethe-Universität der Molekularbiologe Dr. Sotirios Fragkostefanakis.

We describe and illustrate Croton restingae Sodré & Riina sp. nov., a new species endemic to a restricted area in the state of Rio de Janeiro, Brazil, characterized by a particular type of vegetation of the Atlantic Forest known as restinga. The new species belongs to Croton sect. Adenophylli subsect. Laceratoglandulosus, which is supported by morphology and a phylogenetic analysis based on nrDNA ITS sequence data. Croton restingae is most closely related to C. echioides and C. laceratoglandulosus, also in subsect. Laceratoglandulosus, with which it shares the fruit columella with three non-inflated, flat or slightly ascending apical appendages. Croton restingae differs from them by its sessile or shortly stipitate leaf nectaries, revolute pistillate sepals, styles distally 2-fid and basally united forming a column, and larger capsules (7.5–8 × 8.5–9.3 mm). Croton restingaeʼs habitat, conservation status, phenology, morphology and phylogenetic relationships are discussed, and a map with its geographic distribution is also included.

Oceanic islands only comprise a small amount of the Earth’s land area but harbour a disproportionate amount of global biodiversity. This vast diversity is not only reflected in the taxonomic uniqueness of island biota but also in the remarkable evolution of functional traits. Functional traits, i.e. measurable characteristics that strongly influence the fitness of species, determine how a species responds to its environment and can help to gain more insights into the biogeographical, ecological and evolutionary processes that have shaped island biodiversity. However, research in island biogeography has primarily focused on species richness, and knowledge of functional trait patterns on oceanic islands is scarce. Hence, in this dissertation, I have explored how trait-based approaches can increase our understanding of how biodiversity on oceanic islands assembles and how it is driven by the environment. The Canary Islands (Spain) are a particularly suitable model system to investigate patterns and drivers of biodiversity. The archipelago is characterised by a high variation in environmental heterogeneity and inhabits a unique and well-described native flora. Therefore, I have investigated five principal research questions using the flora (Spermatophytes) of the Canary Islands as a study object. First, I have analysed how climate and biogeography shape the assembly of the Canary Islands flora using a novel trait-based approach. Second, the question of whether rare climates link to functional trait distinctiveness in the native Canary Islands flora was addressed. Third, I have examined how intraspecific trait variation is represented in the native flora of oceanic islands focusing on the succulent scrub of La Palma (Canary Islands). Fourth, this dissertation investigated whether scientific floras can be reliable sources for trait data of plants native to oceanic islands. Finally, I have explored how climate change may impact the native Canary Islands flora by analysing, Ozeanische Inseln machen nur einen kleinen Teil der Landfläche der Erde aus, beherbergen aber einen unverhältnismäßig großen Teil der weltweiten Artenvielfalt. Diese enorme Vielfalt spiegelt sich nicht nur in der taxonomischen Einzigartigkeit der Inselbiota wider, sondern auch in der bemerkenswerten evolutionären Entwicklung funktionaler Merkmale. Funktionale Merkmale, d. h. messbare Eigenschaften, die die Fitness von Arten stark beeinflussen, bestimmen, wie eine Art auf ihre Umwelt reagiert. Sie können dazu beitragen mehr Erkenntnisse über die biogeographischen, ökologischen und evolutionären Prozesse zu gewinnen, die die biologische Vielfalt auf Inseln geprägt haben. Die Forschung im Bereich der Inselbiogeographie hat sich bisher jedoch in erster Linie auf den Artenreichtum konzentriert, und den Erkenntnisgewinn über funktionale Merkmalsmuster auf ozeanischen Inseln vernachlässigt. In dieser Dissertation habe ich daher untersucht, wie die Analyse funktionaler Merkmale unser Verständnis dafür verbessern kann, wie sich die biologische Vielfalt auf ozeanischen Inseln zusammengesetzt hat und von ihrer Umwelt beeinflusst wird. Die Kanarischen Inseln (Spanien) sind ein besonders geeignetes Modellsystem, um die Muster und Triebkräfte der biologischen Vielfalt zu untersuchen. Der Archipel zeichnet sich durch eine große Umweltheterogenität aus und beherbergt eine einzigartige und gut beschriebene einheimische Flora. Daher habe ich zur Analyse meiner Forschungsfragen die Flora (Spermatophyten) der Kanarischen Inseln als Studienobjekt herangezogen. Zuerst habe ich analysiert, wie Klima und biogeographische Faktoren die Zusammensetzung der kanarischen Flora beeinflussen, indem ich die funktionale Diversität der Artengemeinschaften entlang von Umweltgradienten untersucht habe. Zweitens hat sich diese Dissertation mit der Frage beschäftigt, ob seltene Klimazonen die funktionalen Merkmale der einheimischen Flora der Kanarischen Inseln beeinflussen. Drittens habe ich untersucht

Several phylogenetic studies have revealed that Murraya s. lat. is not monophyletic, suggesting that it should be split into two genera, namely Murraya s. str. and Bergera J.Koenig ex L. Here, the genus Bergera is comprehensively revised based on molecular and morphological data. The genus consists of 11 species in total, including all species previously placed in Murraya sect. Bergera and an additional species previously placed in Murraya sect. Murraya. Ten new combinations are proposed, namely Bergera alternifolia (Kurz) F.J.Mou comb. nov., B. crenulata (Turcz.) F.J.Mou comb. nov., B. euchrestifolia (Hayata) F.J.Mou comb. nov., B. glabra (Guillemin) F.J.Mou comb. nov., B. kwangsiensis (C.C.Huang) F.J.Mou comb. nov., B. macrophylla (C.C.Huang) F.J.Mou comb. nov., B. microphylla (Merr. & Chun) F.J.Mou comb. nov., B. siamensis (Craib) F.J.Mou comb. nov., B. stenocarpa (Drake) F.J.Mou comb. nov., and B. tetramera (C.C.Huang) F.J.Mou comb. nov. An identification key of the 11 species and morphological descriptions are provided, as well as illustrations of diagnostic characteristics. Phylogenetic relationships of the species in Bergera are discussed.

We provide a floristic account for the Begoniaceae of Peru. The family is represented in Peru by 76 species, which are all members of the genus Begonia and represent eighteen sections. Twelve new species are described: B. condorensis Jara & Moonlight sp. nov., B. deltoides Moonlight sp. nov., B. huancabambae Moonlight sp. nov., B. imbrexiformis Moonlight sp. nov., B. longinqua Moonlight sp. nov., B. longitepala Moonlight sp. nov., B. nunezii Moonlight sp. nov., B. occultata J.P.Allen & Moonlight sp. nov., B. pedemontana Moonlight sp. nov., B. serratistipula Moonlight sp. nov., B. vargasii Moonlight sp. nov. and B. yuracyacuensis Moonlight sp. nov. We also provide four new records for the country: B. andina Rusby, B. brandbygeana L.B.Sm. & Wassh., B. neoharlingii L.B.Sm. & Wassh. and B. unilateralis Rusby. We provide an identification key to all species. The ecology, distribution, and conservation status of all Peruvian Begonia species are discussed, including provisional IUCN threat assessments. Most species are illustrated by either historical illustrations, contemporary photographic plates, or line drawings. Twenty-six names are newly synonymised including fifteen previously accepted species, and we designate eighty-three lectotypes, four neotypes, and four epitypes.

One of the reasons for the high efficiency and selectivity of biological catalysts arise from their ability to control the pathways of substrates and products using protein channels, and by modulating the transport in the channels using the interaction with the protein residues and the water/hydrogen-bonding network. This process is clearly demonstrated in Photosystem II (PS II), where its light-driven water oxidation reaction catalyzed by the Mn4CaO5 cluster occurs deep inside the protein complex and thus requires the transport of two water molecules to and four protons from the metal center to the bulk water. Based on the recent advances in structural studies of PS II from X-ray crystallography and cryo-electron microscopy, in this review we compare the channels that have been proposed to facilitate this mass transport in cyanobacteria, red and green algae, diatoms, and higher plants. The three major channels (O1, O4, and Cl1 channels) are present in all species investigated; however, some differences exist in the reported structures that arise from the different composition and arrangement of membrane extrinsic subunits between the species. Among the three channels, the Cl1 channel, including the proton gate, is the most conserved among all photosynthetic species. We also found at least one branch for the O1 channel in all organisms, extending all the way from Ca/O1 via the ‘water wheel’ to the lumen. However, the extending path after the water wheel varies between most species. The O4 channel is, like the Cl1 channel, highly conserved among all species while having different orientations at the end of the path near the bulk. The comparison suggests that the previously proposed functionality of the channels in T. vestitus (Ibrahim et al., Proc Natl Acad Sci USA 117:12624–12635, 2020; Hussein et al., Nat Commun 12:6531, 2021) is conserved through the species, i.e. the O1-like channel is used for substrate water intake, and the tighter Cl1 and O4 channels for proto, Peer Reviewed

The development of photosynthetically competent seedlings requires both light and retrograde biogenic signaling pathways. The transcription factor GLK1 functions at the interface between these pathways and receives input from the biogenic signal integrator GUN1. BBX14 was previously identified, together with GLK1, in a core module that mediates the response to high light (HL) levels and biogenic signals, which was studied by using inhibitors of chloroplast development. Our chromatin immunoprecipitation-Seq experiments revealed that BBX14 is a direct target of GLK1, and RNA-Seq analysis suggests that BBX14 may function as a regulator of the circadian clock. In addition, BBX14 plays a role in chlorophyll biosynthesis during early onset of light. Knockout of BBX14 results in a long hypocotyl phenotype dependent on a retrograde signal. Furthermore, the expression of BBX14 and BBX15 during biogenic signaling requires GUN1. Investigation of the role of BBX14 and BBX15 in GUN-type biogenic (gun) signaling showed that the overexpression of BBX14 or BBX15 caused de-repression of CA1 mRNA levels, when seedlings were grown on norflurazon. Notably, transcripts of the LHCB1.2 marker are not de-repressed. Furthermore, BBX14 is required to acclimate plants to HL stress. We propose that BBX14 is an integrator of biogenic signals and that BBX14 is a nuclear target of retrograde signals downstream of the GUN1/GLK1 module. However, we do not classify BBX14 or BBX15 overexpressors as gun mutants based on a critical evaluation of our results and those reported in the literature. Finally, we discuss a classification system necessary for the declaration of new gun mutants., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Peer Reviewed

Arbuscular mycorrhizal fungi (AMF) alter plant water relations and contribute to soil structure. Although soil hydraulic properties depend on soil structure and may limit plant water uptake, little is known about how AMF influence soil water retention (the relation between the soil water content and soil water potential) and hydraulic conductivity in different soils. Instead, these soil hydraulic properties often are considered to be independent of AMF presence in experiments. We asked if this assumption holds true for both sand and loam. We grew maize plants either inoculated with Rhizophagus irregularis or with autoclaved inoculum in pots filled with quartz sand or loam soil until extraradical spread of the fungus throughout the pots was achieved. Each pot contained a hyphal compartment made of a soil sampling core (250 cm3) covered with a 20-µm nylon mesh to encourage fungus ingrowth but to exclude root ingrowth. We measured soil water retention and unsaturated hydraulic conductivity in these undisturbed root-free soil volumes. We observed that in loam harboring the mycorrhizal fungus, the soil water retention decreased, while in sand, it increased without detectable changes in the soil bulk density. The effects of the fungus on the soil water potential were strongest at low soil water contents in both soils. As a consequence of the altered water potentials in soils with the mycorrhizal fungus, soil hydraulic conductivity increased in loam but decreased in sand after fungus ingrowth. We conclude that in our study, the mycorrhizal fungus acted as a soil conditioner even distant from roots, which encouraged drainage in loams prone to sogginess but enhanced water storage in sands prone to quick desiccation. We recommend considering soil hydraulic properties as being dynamic in future studies on water relations of mycorrhizal plants., Peer Reviewed