Luticola tenera sp. nov. (Diadesmidaceae, Naviculales)-A New Diatom from the Soil of the State Nature Reserve "Bastak" (Jewish Autonomous Region, Russia)

Diatoms inhabit different aquatic and non-aquatic environments, including soils. The naviculoid genus Luticola is widespread in various habitats and accounts for 264 species that are only based on morphological and morphometric characteristics. These parameters can greatly vary during the life cycle, making the species very similar to each other and complicating their unambiguous identification. During a study on soil algal diversity in the Russian Far East (Jewish Autonomous Region), we isolated a strain of naviculoid diatom and examined it using an integrative approach (phylogenetic, morphological, ultrastructural data, and life cycle). Phylogenetic analyses, based on chloroplast rbcL gene data, showed affinity of the new strain with the genus Luticola. Our alga shares morphological features typical of the genus members but differs from them by having valves with a larger width and hook-shaped external proximal raphe ends deflected to the side opposite the stigma. It was revealed that the strain reproduces via two types of sexual reproduction-isogamy and cis-anisogamy. Based on these phenotypic traits, we described the new isolate as Luticola tenera sp. nov.

Microscopic techniques for characterization and authentication of oil-yielding seeds

Investigation of alternative energy sources is need of current time due to growing power crisis and associated environmental issues. Biodiesel is considered as sustainable power source and promising alternative to fossil fuels. Therefore, our current investigation aimed to identify micromorphological characters of 10 novel nonedible oil-yielding seeds through scanning electron microscopy. It was revealed from light microscopic study that there is variation in seed size from 3 to 15 mm in length and 2 to 11 mm in width. Likewise, a huge variation in color was observed such as light green, greenish yellow, blackish brown, and various shades of brown. Presence and absence of Hilum was observed, and compression of seeds varied from depressed, lateral, and dorsoventral. Seed's shape differs from ovate, clavate, triangular ovate, cuneiform, ovoid, and elliptical shape. Seed oil content fall in range of 18-58% (wt/wt). Free fatty acid content of the seeds varies from 0.3 to 3.1 mg KOH/g. Ultrastructure of seeds exhibited huge variation in shape, size, periclinal wall, anticlinal wall, and surface ornamentation. Nonedible seeds varied in wall structure from angular, wavy, dentate entire, irregular, puzzled, elongated, even, and polygonal. The periclinal wall arrangements show alteration from flat, looped, raised, depressed, lofty, even, pentagonal, polygonal, and undulate seed margins. Outcomes of this investigation recommended that scanning electron microscopy could act as a helpful tool in disclosing the hidden micromorphological characters among nonedible oil-yielding seeds and subsequently helping in correct, authentic seed identification and classification as potential feedstock for biodiesel.

Morphological and palynological assessment of some taxa of genus Echinochloa through light and scanning electron microscopy

The present study was undertaken to gather information on selected species of Echinochloa based on their morphological and palyonological examination through light and scanning electron microscopy. As the Echinochloa species are most problematic grass weeds and exhibit high interspecific and intraspecific variability so due to their great morphological diversity it is difficult to recognize them. A lot of variation was observed in morphological features of studied taxa. In the present study, E. colona had more or less spreading dense racemes whereas in E. crus-galli racemes were linear to ovate. Upper glume surface was pubescent in E. colona, hispid in E. crus-galli and spinose in E. walteri. E. colona was comprised of five-nerved glumes whereas in E. crus-galli glumes were three-nerved. Although pollen basic characters in family Poaceae remains consistent but great variation was observed in pollen of studied taxa. The pollen size was quite variable among the species of genus Echinochloa. In polar view, the size of pollen grains ranged from 27.5 (20-35) μm to 40 (30-50) μm. E. crus-galli was appeared to be the smallest in size whereas E. colona was the largest.). P/E ratio ranged from 0.84 to 1.15 μm among the species. The highest value of pollen fertility was found in E. colona as 93.33% and lowest was in E. crus-galli as 87.50%. The morphological key of studied taxa is also given to study variations. In conclusion, it was observed that microscopy of morphological and palynological assessment can play a vital role in identification of taxonomically problematic taxa.

Effect of necrotrophic fungus and PGPR on the comparative histochemistry of Vigna radiata by using multiple microscopic techniques

Rapid advances in the field of pathogen detection have opened new opportunities and better understanding for their management approaches. Aim of this study was to elucidate histopathological observations of different tissues affected by Macrophomina phaseolina and to observe the defense responses of plant growth promoting rhizobacteria (PGPR) in mungbean plants. Sections of the stem and root were prepared and stained with ferric chloride, Lugol's iodine and Wiesner's reagent and were then observed under multiple microscopic techniques. Results revealed that both pathogen and PGPR produce responses on the plant that include colonization of xylem vessels by hyphae and sclerotia, hypertrophy and hyperplasia of the cells, destruction of xylem fibers and amyloplasts in parenchymatous cells; and production of gels by the plant were observed. There was a significant increase in lignin and phenolic compounds deposition in stem and root sections of PGPR treated and non-treated mungbean plants. Whereas the soil amended with PGPR showed very less to no starch production. Moreover, production of gels and gums were also observed in both stem and root sections. Compared to light microscopy, scanning electron microscope provided greater depth of focus and resolution of the pathogen attack on plant tissues, associated bacteria. As a whole, the data demonstrated that inoculation of PGPR can be an effective strategy to stimulate plant growth and they could significantly activate disease resistance against M. phaseolina.

Messinian vegetation and climate of the intermontane Florina-Ptolemais-Servia Basin, NW Greece inferred from palaeobotanical data: how well do plant fossils reflect past environments?

The late Miocene is marked by pronounced environmental changes and the appearance of strong temperature and precipitation seasonality. Although environmental heterogeneity is to be expected during this time, it is challenging to reconstruct palaeoenvironments using plant fossils. We investigated leaves and dispersed spores/pollen from 6.4 to 6 Ma strata in the intermontane Florina-Ptolemais-Servia Basin (FPS) of northwestern Greece. To assess how well plant fossils reflect the actual vegetation of the FPS, we assigned fossil taxa to biomes providing a measure for environmental heterogeneity. Additionally, the palynological assemblage was compared with pollen spectra from modern lake sediments to assess biases in spore/pollen representation in the pollen record. We found a close match of the Vegora assemblage with modern Fagus-Abies forests of Turkey. Using taxonomic affinities of leaf fossils, we further established close similarities of the Vegora assemblage with modern laurophyllous oak forests of Afghanistan. Finally, using information from sedimentary environment and taphonomy, we distinguished local and distantly growing vegetation types. We then subjected the plant assemblage of Vegora to different methods of climate reconstruction and discussed their potentials and limitations. Leaf and spore/pollen records allow accurate reconstructions of palaeoenvironments in the FPS, whereas extra-regional vegetation from coastal lowlands is probably not captured.