Members of the ELMOD protein family specify formation of distinct aperture domains on the Arabidopsis pollen surface

Pollen apertures, the characteristic gaps in pollen wall exine, have emerged as a model for studying the formation of distinct plasma membrane domains. In each species, aperture number, position, and morphology are typically fixed; across species they vary widely. During pollen development, certain plasma membrane domains attract specific proteins and lipids and become protected from exine deposition, developing into apertures. However, how these aperture domains are selected is unknown. Here, we demonstrate that patterns of aperture domains in Arabidopsis are controlled by the members of the ancient ELMOD protein family, which, although important in animals, has not been studied in plants. We show that two members of this family, MACARON (MCR) and ELMOD_A, act upstream of the previously discovered aperture proteins and that their expression levels influence the number of aperture domains that form on the surface of developing pollen grains. We also show that a third ELMOD family member, ELMOD_E, can interfere with MCR and ELMOD_A activities, changing aperture morphology and producing new aperture patterns. Our findings reveal key players controlling early steps in aperture domain formation, identify residues important for their function, and open new avenues for investigating how diversity of aperture patterns in nature is achieved.

The anatomical, palynological and micromorphological aspects of three endemic Bellevalia species (Asparagaceae) in Turkey and their taxonomic importance

In the present research, anatomical, palynological and micromorphological characteristics of three endemic Bellevalia species (B. gracilis, B. malatyaensis and B. vuralii) for Turkey are carried out. This work reveals the descriptive characteristics of the examined species, and contribute to solving taxonomic problems. Anatomical studies were carried out on cross sections of root, scape and leaf. The metaxylem, the number of root cortex cells, and the number of cortex and sclerenchyma cells in the scape were found to be significant in terms of taxonomy. Pollen grains of all the examined species were monosulcate and heteropolar. In addition, seed and pollen surface ornamentation were photographed under SEM microscopy, which SEM micrographs showed that the exine sculpturing pattern is reticulate-perforate, and pollen muri walls of were different among the examined species. Conversely, seeds showed a general similarity of the surface among the studied species, all showing a reticulate faveolate ornamentation.

Climate reconstructions based on GDGT and pollen surface datasets from Mongolia and Baikal area: calibrations and applicability to extremely cold–dry environments over the Late Holocene

Our understanding of climate and vegetation changes throughout the Holocene is hampered by representativeness in sedimentary archives. Potential biases such as production and preservation of the markers are identified by comparing these proxies with modern environments. It is important to conduct multi-proxy studies and robust calibrations on each terrestrial biome. These calibrations use large databases dominated by forest samples. Therefore, including data from steppe and desert–steppe sites becomes necessary to better calibrate arid environments. The Mongolian Plateau, ranging from the Baikal area to the Gobi desert, is especially characterized by low annual precipitation and continental annual air temperature. The characterization of the climate system of this area is crucial for the understanding of Holocene monsoon oscillations. This study focuses on the calibration of proxy–climate relationships for pollen and glycerol dialkyl glycerol tetraethers (GDGTs) by comparing large Eurasian calibrations with a set of 49 new surface samples (moss polster, soil and mud from temporary dry ponds). These calibrations are then cross-validated by an independent dataset of top-core samples and applied to four Late Holocene paleosequences (two brGDGT and two pollen records) surrounding the Mongolian Plateau: in the Altai mountains, the Baikal area and the Qaidam basin, to test the accuracy of local and global calibrations. We show that (1) preserved pollen assemblages are clearly imprinted on the extremities of the ecosystem range but mitigated and unclear on the ecotones; (2) for both proxies, inferred relationships depend on the geographical range covered by the calibration database as well as on the nature of samples; (3) even if local calibrations suffer from reduced amplitude of climatic parameters due to local homogeneity, they better reflect actual climate than the global ones by reducing the limits for saturation impact; (4) a bias in climatic reconstructions is induced by the over-parameterization of the models by the addition of artificial correlation; and (5) paleoclimate values reconstructed here are consistent with Mongolia–China Late Holocene climate trends and validate the application of local calibrations for both pollen and GDGTs (closest fit to actual values and realistic paleoclimate amplitude). We encourage the application of this surface calibration method to reconstruct paleoclimate and especially consolidate our understanding of the Holocene climate and environment variations in arid central Asia.

Members of the ELMOD protein family specify formation of distinct aperture domains on the Arabidopsis pollen surface

Pollen apertures, the characteristic gaps in pollen wall exine, have emerged as a model for studying the formation of distinct plasma-membrane domains. In each species, aperture number, position, and morphology are typically fixed; across species they vary widely. During pollen development certain plasma-membrane domains attract specific proteins and lipids and become protected from exine deposition, developing into apertures. However, how these aperture domains are selected is unknown. Here, we demonstrate that patterns of aperture domains in Arabidopsis are controlled by the members of the ancient ELMOD protein family, which, although important in animals, has not been studied in plants. We show that two members of this family, MACARON (MCR) and ELMOD_A, act upstream of the previously discovered aperture proteins and that their expression levels influence the number of aperture domains that form on the surface of developing pollen grains. We also show that a third ELMOD family member, ELMOD_E, can interfere with MCR and ELMOD_A activities, changing aperture morphology and producing new aperture patterns. Our findings reveal key players controlling early steps in aperture domain formation, identify residues important for their function, and open new avenues for investigating how diversity of aperture patterns in nature is achieved.

Morphology and molecules support the new monotypic genus Parainvolucrella (Rubiaceae) from Asia

Parainvolucrella R.J. Wang, a new monotypic genus is segregated from Hedyotis-Oldenlandia complex based on the morphological and molecular evidences, along with the new combination of P. scabra (Wall. ex Kurz) M.D.Yuan & R.J.Wang. The new genus is phylogenetically sister to Scleromitrion and has ever been mistaken as a member of Scleromitrion, but its perennial woody herbaceous habit, terminal inflorescence, heterostylous flowers, indehiscent capsules, and microreticulate with smooth muri pollen surface ornamentation make it different from the latter. A key for all the genera of this complex in China is provided as well.

Climate reconstructions based on GDGT and pollen surface datasets from Mongolia and Siberia: calibrations and applicability to extremely cold-dry environments over the Late Holocene

Our understanding of climate and vegetation changes throughout the Holocene is hampered by representativeness in sedimentary archives. Potential biases such as production and preservation of the markers are identified by comparing these proxies with modern environments. It is important to conduct multi-proxy studies and robust calibrations on each terrestrial biome. These calibrations use large data base dominated by forest samples. Therefore, including data from taiga and steppe sites becomes mandatory to better calibrate arid environments. The Mongolian plateau, ranging from the Baikal basin to the Gobi desert, is especially characterized by low annual precipitation and continental annual air temperature. The characterization of the climate system of this area is crucial for the understanding of Holocene Monsoon Oscillations. This study focuses on the calibration of proxy-climate relationships for pollen and glycerol dialkyl glycerol tetraethers (GDGTs) by comparing large published Eurasian calibrations with a set of 49 new surface samples (moss polster, soil and mud from temporary dry pond). These calibrations are then cross-validated by an independent dataset of top-core samples and applied to two Late Holocene paleosequences in the Altai mountains and the Qaidam basin. We show that: (1) preserved pollen assemblages are clearly imprinted on the extremities of the ecosystem range but mitigated and unclear on the ecotones; (2) for both proxies, inferred relationships depend on the geographical range covered by the calibration database as well as on the nature of samples; (3) even if local calibrations suffer from reduced amplitude of climatic parameter due to local homogeneity, they better reflect actual climate than the global ones by reducing the limits for saturation impact, (4) a bias in climatic reconstructions is induced by the over-parameterization of the models by addition of artificial correlation and (5) paleoclimate values reconstructed here are consistent with Mongolia-China Late Holocene climate trends, and validate the application of local calibrations for both pollen and GDGTs (closest fit to actual values and realistic paleoclimate amplitude). We encourage the application of this surface calibration method to reconstruct palaeoclimate and especially consolidate our understanding of the Holocene climate and environment variations in Arid Central Asia.

STUDY OF THE CYTOLOGICAL AND MICRO-MORPHOLOGICAL CHARACTERISTICS OF SOME SPECIES OF THE GENUS EUPHORBIA L.BELONG TO EUPHORBIACEAE FAMILY , USING ELECTRON MICROSCOPE IN IRAQ

This study was aimed to investigate micro-morphological and cytological characteristics for sex species of Euphorbiaceae family in Baghdad during the two growing seasons 2018-2019 . The species are: Euphorbia granulate Forssk.,E.helioscopia L.,E. hirta L.,E. hypericifolia L., E. milli Des Moul .,E. puplus L. Which involved with morphological characters of pollen grains and seeds, as well the chromosomes number, and the study managed to count chromosome number for the above species sequentially:-n=11, n=21, n=9, n=16, n=14,18, n=7,8. The morphological characters of pollen grains surface has been studied by using scanning electron microscope (SEM), shape and size, polar and equatorial axes, spines length, dimensions of ora and colpi, and the ornamentations on pollen surface, and it has been observed that all the species are tri-zono-colporate, spinulose and spinate (echinated), and spinolophate fruite, and importance of the pollen grains in taxonomy. The study includes morphological characteristics of seeds by using (SEM) In terms of size, shape, color, and appearance of the seed surface(configuration). It has been shown that the seeds are significantly different from species to another. Species help to isolate and classify, and through relying on these characteristics, classification limits could be set, whether at the level of species or genus within each family.

The Eurasian Modern Pollen Database (EMPD), version 2

The Eurasian (née European) Modern Pollen Database (EMPD) was established in 2013 to provide a public database of high-quality modern pollen surface samples to help support studies of past climate, land cover, and land use using fossil pollen. The EMPD is part of, and complementary to, the European Pollen Database (EPD) which contains data on fossil pollen found in Late Quaternary sedimentary archives throughout the Eurasian region. The EPD is in turn part of the rapidly growing Neotoma database, which is now the primary home for global palaeoecological data. This paper describes version 2 of the EMPD in which the number of samples held in the database has been increased by 60 % from 4826 to 8134. Much of the improvement in data coverage has come from northern Asia, and the database has consequently been renamed the Eurasian Modern Pollen Database to reflect this geographical enlargement. The EMPD can be viewed online using a dedicated map-based viewer at https://empd2.github.io and downloaded in a variety of file formats at https://doi.pangaea.de/10.1594/PANGAEA.909130 (Chevalier et al., 2019).

SERS activity of hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template

Nature provides remarkable examples of mass-produced microscale particles with structures and chemistries optimized by evolution for particular functions. Synthetic chemical tailoring of such sustainable biogenic particles may be used to generate new multifunctional materials. Herein, we report a facile method for the synthesis of hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template. Silver nanoparticles was biosynthesized using pollen grains as a reduction and stabilization agent as well as a bio-template promoting the adhesion of silver nanoparticles to pollen surface. Fe3O4 nanoparticles were synthesized by co-precipitation method from FeSO4. Hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template were obtained and characterized using Scanning Electron Microscopy and Transmission Electron Microscopy to study the morphology and structure; Energy-Dispersive X-ray Spectroscopy to determine the chemical composition distribution; and Confocal Fluorescence Microscopy to demonstrate the fluorescence properties of hybrid nano-microstructures. Furthermore, these hybrid nano-microstructures have been studied by Surface-Enhanced Raman Scattering (SERS), using methylene blue as a target molecule; the hybrid nano-microstructures have shown 14 times signal amplification.