- Pollen micromorphological analysis of tribe Acacieae (Mimosaceae) with LM and SEM techniques. [Journal Article]
- MRMicrosc Res Tech 2019 Jul 03
- The morphology of pollen grains of the 06 species of tribe Acacieae (Mimosaceae) belonging to one genus were investigated using scanning electron microscopic (SEM) and light microscopic (LM) approach…
The morphology of pollen grains of the 06 species of tribe Acacieae (Mimosaceae) belonging to one genus were investigated using scanning electron microscopic (SEM) and light microscopic (LM) approach. Lactic acid acetolysis method was used for (LM) while non-acetolysis for (SEM). The species were examined for the both qualitative and quantitative palynological features. Qualitatively the pollen was studied for the shape, exine sculpturing, pollen shape, and pollen type. Oblate spheroidal shape of pollen was observed in Accacia modesta. Subprolate shape in Accaca nilotica. In Accacia farnesiana, prolate pollen was examined while prolate spheroidal in Acacia tortilis and spheroidal pollen grains were studied in Acacia catechu, respectively. Pollen exine sculpturing of the studied tribe possesses novel variation. Foveolate, reticulate, foveolate-psilate, faint reticulate, fossulate, perforate, and scrabate exine sculpturing were noticed. Colpi were absent in all species. Excessive variation was observed in both qualitative and quantitative character of pollen. SPSS software was use for the quantitative measurement of the pollen grains. The current study will be helpful for the identification of the problematic species and phylogenetic studies of family Mimosaceae.
- Pollen morphological variation of Berberis L. from Pakistan and its systematic importance. [Journal Article]
- MRMicrosc Res Tech 2019 Jun 27
- Due to overlapping and diverse morphological characters, Berberis is among the most taxonomically complex genera. Palynology is one of the taxonomic tools for delimitation and identification of compl…
Due to overlapping and diverse morphological characters, Berberis is among the most taxonomically complex genera. Palynology is one of the taxonomic tools for delimitation and identification of complex species. In this study, pollens of 10 Berberis species were analyzed through light and scanning electron microscopy. Qualitative as well as quantitative features (pollen shape, size, presence or absence of colpi, colpi length and width, exine thickness, ornamentation, pollen class, aperture, and polar-equatorial ratio) were measured. Five species were observed to have colpate (pantocolpate) with elongated ends, radially symmetrical, isopolar, monads, and psilate-regulate pollens. In polar view, six pollen were spheroidal, two were ovoid, one spherical, and one oblate. Similarly, variation in pollen length was prominent and the largest pollen on polar view was recorded for B. psodoumbellata 60-65 μm (62.4 ± 0.9), while the smallest one was observed for B. lycium 29-35 μm (32.2 ± 1). The observed variation in both quantitative and qualitative features were important in taxonomic identification. This shows that palynological characters are helpful in identification of Berberis genus at the species level.
- Widespread Warming Before and Elevated Barium Burial During the Paleocene-Eocene Thermal Maximum: Evidence for Methane Hydrate Release? [Journal Article]
- PPPaleoceanogr Paleoclimatol 2019; 34(4):546-566
- Current climate change may induce positive carbon cycle feedbacks that amplify anthropogenic warming on time scales of centuries to millennia. Similar feedbacks might have been active during a phase …
Current climate change may induce positive carbon cycle feedbacks that amplify anthropogenic warming on time scales of centuries to millennia. Similar feedbacks might have been active during a phase of carbon cycle perturbation and global warming, termed the Paleocene-Eocene Thermal Maximum (PETM, 56 million years ago). The PETM may help constrain these feedbacks and their sensitivity to warming. We present new high-resolution carbon isotope and sea surface temperature data from Ocean Drilling Program Site 959 in the Equatorial Atlantic. With these and existing data from the New Jersey Shelf and Maud Rise, Southern Ocean, we quantify the lead-lag relation between PETM warming and the carbon input that caused the carbon isotope excursion (CIE). We show ~2 °C of global warming preceded the CIE by millennia, strongly implicating CO2-driven warming triggered a positive carbon cycle feedback. We further compile new and published barium (Ba) records encompassing continental shelf, slope, and deep ocean settings. Based on this compilation, we calculate that average Ba burial rates approximately tripled during the PETM, which may require an additional source of Ba to the ocean. Although the precipitation pathway is not well constrained, dissolved Ba stored in sulfate-depleted pore waters below methane hydrates could represent an additional source. We speculate the most complete explanation for early warming and rise in Ba supply is that hydrate dissociation acted as a positive feedback and caused the CIE. These results imply hydrates are more temperature sensitive than previously considered, and may warrant reconsideration of the political assignment of 2 °C warming as a safe future scenario.
- Assessment of Pollen Diversity Available to Honey Bees (Hymenoptera: Apidae) in Major Cropping Systems During Pollination in the Western United States. [Journal Article]
- JEJ Econ Entomol 2019 Jun 25
- Global western honey bee, Apis mellifera (L.) (Hymenoptera: Apidae), colony declines pose a significant threat to food production worldwide. Poor nutrition resulting from habitat loss, extensive mono…
Global western honey bee, Apis mellifera (L.) (Hymenoptera: Apidae), colony declines pose a significant threat to food production worldwide. Poor nutrition resulting from habitat loss, extensive monocultures, and agricultural intensification is among the several suggested drivers for colony declines. Pollen is the primary source of protein for honey bees; therefore, both pollen abundance and diversity are critical for colony growth and survival. Many cropping systems that employ honey bee colonies for pollination may lack sufficient pollen diversity and abundance to provide optimal bee nutrition. In this observational study, we documented the diversity and relative abundance of pollen collected by honey bees in five major pollinator-dependent crops in the western United States. We sampled pollen from pollen traps installed on honey bee colonies in the following cropping systems-almond, cherry, highbush blueberry, hybrid carrot, and meadowfoam. The pollen diversity was estimated by documenting the number of different pollen pellet colors and plant taxa found in each pollen sample. The lowest pollen diversity was found in almond crop. Relatively higher quantities of pollen collection were collected in almond, cherry, and meadowfoam cropping systems. The information gleaned from this study regarding pollen diversity and abundance may help growers, land managers, and beekeepers improve pollen forage available to bees in these cropping systems.
- Palynological data of cores MSM5/5-712-2 and PS2863/1-2 from northeastern Fram Strait spanning the last glacial maximum to present. [Journal Article]
- DBData Brief 2019; 24:103899
- The palynogical data of two sites from northeastern Fram Strait (MSM5/5-712 and PS2863) encompassing the last 23,000 years are presented here. The data set first includes the palynomorph concentratio…
The palynogical data of two sites from northeastern Fram Strait (MSM5/5-712 and PS2863) encompassing the last 23,000 years are presented here. The data set first includes the palynomorph concentrations: dinocysts (cysts/g) and their fluxes (cysts/cm2/yr) as well as pollen grains, spores, organic linings, Halodinium, reworked palynomorphs and Pediastrum represented in #/g. It also includes the relative abundance (%) of dinocyst taxa at sites MSM5/5-712 and PS2863. Finally, this Data in Brief comprises reconstructions of sea-surface conditions at the two sites, which include sea-surface temperature (°C) in summer and winter, sea-surface salinity (psu) in summer and winter, sea-ice cover (month/yr) and productivity (gC/m2yr). The most probable values in addition to minimum and maximum possible are reported. The data is presented in function of the cores depth and age. For more details on this data and the chronology of the cores, see .
- Specialized metabolites contributing to colour and scent volatiles in Uvaria hamiltonii flowers. [Journal Article]
- NPNat Prod Res 2019 Jun 11; :1-4
- The present study focuses on the emitted and endogenous scent profiles of Uvaria hamiltonii flowers. Among the 34 compounds identified, sesquiterpenoids were found to dominate the floral volatiles co…
The present study focuses on the emitted and endogenous scent profiles of Uvaria hamiltonii flowers. Among the 34 compounds identified, sesquiterpenoids were found to dominate the floral volatiles composition. Profiles from endogenous scent volatiles showed higher number of compounds than the emitted ones. The anthocyanin pigment responsible for the flower colour was also explored. It was found that a single anthocyanin compound, cyanidin-3-O-glucoside, was principally responsible for petal colour. Total phenolic content was evaluated and antioxidant capacities were studied with the help of DPPH, FRAP and ABTS assays. The total phenolic content and the antioxidant capacity were higher in methanolic extract as compared to aqueous, petroleum ether and ethyl acetate extracts of U. hamiltonii flowers.
- Palyno-morphological investigations of subtropical endangered flora of Capparidaceae through light and scanning electron microscopy. [Journal Article]
- MRMicrosc Res Tech 2019 May 20
- The research was performed to investigate pollen morphology of endangered species of Capparidaceae in subtropical regions of Pakistan. The distinguishing characters were investigated by using light m…
The research was performed to investigate pollen morphology of endangered species of Capparidaceae in subtropical regions of Pakistan. The distinguishing characters were investigated by using light microscope and scanning electron microscope. Palynological study is comprised of pollen shape, pollen type, exine sculpturing, polar and equatorial diameter, length and width of colpi, mesocolpium, and exine thickness. In polar view, Cleome viscosa exhibited the highest pollen size 26.4 (32.7-24.5 μm) ±0.776 whereas Capparis spinosa appeared to be the lowest 12.6 (14.5-10.7 μm) ±0.400. In equatorial view, Cleome viscosa had the largest pollen size 17.1 (20.0-15.0 μm) ±0.606 and Capparis spinosa had the smallest pollen size 9.7 (12.50-8.00 μm) ±0.394. The maximum fertility percentage has been observed in Capparis spinosa, that is, 98.96% and minimum in Cleome viscosa, that is, 82.93%. Diagnostic key has been constructed to state the essential diagnostic features by means of which the taxa can be identified. Remarkable variations have been observed in pollen size, shape, and exine sculpturing. All the selected species were tricolporate. Prolate to subprolate pollen were observed. There is a great variation existed in exine sculpturing such as in Capparis decidua and C. sp. nova sculpturing is reticulate, in Capparis himalayensis sculpturing is Scabrate granulate, in Capparis spinosa sculpturing is Psilate, in Cleome viscosa sculpturing is regulate-reticulate, in Dipterygium glaucum sculpturing is regulate and in Gynandropsis gynandra sculpturing is striate-regulate. On the basis of overall characteristics of pollen it seems that palynology of this family is helpful at the generic and specific level.
- Strontium and stable isotope evidence of human mobility strategies across the Last Glacial Maximum in southern Italy. [Journal Article]
- NENat Ecol Evol 2019; 3(6):905-911
- Understanding the reason(s) behind changes in human mobility strategies through space and time is a major challenge in palaeoanthropology. Most of the time this is due to the lack of suitable tempora…
Understanding the reason(s) behind changes in human mobility strategies through space and time is a major challenge in palaeoanthropology. Most of the time this is due to the lack of suitable temporal sequences of human skeletal specimens during critical climatic or cultural shifts. Here, we present temporal variations in the Sr isotope composition of 14 human deciduous teeth and the N and C stable isotope ratios of four human remains from the Grotta Paglicci site (Apulia, southern Italy). The specimens were recovered from the Gravettian and Epigravettian layers, across the Last Glacial Maximum, and dated between 31210-33103 and 18334-19860 yr cal BP (2σ). The two groups of individuals exhibit different 87Sr/86Sr ratios and, while the Gravettians are similar to the local macro-fauna in terms of Sr isotopic signal, the Epigravettians are shifted towards higher radiogenic Sr ratios. These data, together with stable isotopes, can be explained by the adoption of different mobility strategies between the two groups, with the Gravettians exploiting logistical mobility strategies and the Epigravettians applying residential mobility.
- Quantitative analysis of diverse sporomorph-derived sporopollenins. [Journal Article]
- PPhytochemistry 2019; 162:207-215
- Over the years studies on sporopollenin have reported a wide variety of structures. However, the methods and techniques used to elucidate sporopollenin structures are highly diverse so that much is s…
Over the years studies on sporopollenin have reported a wide variety of structures. However, the methods and techniques used to elucidate sporopollenin structures are highly diverse so that much is still unclear with respect to the nature and structural diversity of sporopollenins. In order to investigate the structural diversity in sporopollenin between different taxa, extant sporomorphs of ten different species ranging from a mushroom to a cycad were examined using a relatively simple and fast analytical procedure. Sporomorphs, before and after saponification, were analysed for sporopollenin composition by Thermally assisted Hydrolysis and Methylation (THM) using [13C]tetramethylammonium hydroxide ([13C]TMAH). The sporomorp chemical composition differed markedly between the groups of organisms analysed. Moreover, we not only identified the nature and relative quantities of the well-known sporopollenin constituents p-coumaric acid and ferulic acid but also many other phenolic moieties, such as caffeic acid, which appeared to be the most abundant phenolic constituent in spores of Equisetum palustre, Salvinia molesta, Cyrtomium falcatum and Anemia phyllitidis. Within the two Equisetum species analysed as well as in the closely related Azolla and Salvinia species the same suite of phenolic constituents were observed, but their relative distribution varied largely. We thus demonstrate the existence of a high structural diversity, both qualitatively and quantitatively in sporopollenins enabling future studies related to the evolution, phylogeny and (palaeo)environment of sporopollenin-producing organisms. Furthermore, a better knowledge of sporopollenin and its structural variety is of relevance to the rapidly growing application of spores and pollen as a drug delivery agent in medicine.
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- Tracking Pesticide Residues to a Plant Genus Using Palynology in Pollen Trapped from Honey Bees (Hymenoptera: Apidae) at Ornamental Plant Nurseries. [Journal Article]
- EEEnviron Entomol 2019 04 03; 48(2):351-362
- Worldwide studies have used the technique of pollen trapping, collecting pollen loads from returning honey bee (Apis mellifera L.) (Hymenoptera: Apidae) foragers, to evaluate the exposure of honey be…
Worldwide studies have used the technique of pollen trapping, collecting pollen loads from returning honey bee (Apis mellifera L.) (Hymenoptera: Apidae) foragers, to evaluate the exposure of honey bees to pesticides through pollen and as a biomonitoring tool. Typically, these surveys have found frequent contamination of pollen with multiple pesticides, with most of the estimated risk of acute oral toxicity to honey bees coming from insecticides. In our survey of pesticides in trapped pollen from three commercial ornamental plant nurseries in Connecticut, we found most samples within the range of acute toxicity in a previous state pollen survey, but a few samples at one nursery with unusually high acute oral toxicity. Using visual sorting by color of the pollen pellets collected in two samples from this nursery, followed by pesticide analysis of the sorted pollen and palynology to identify the plant sources of the pollen with the greatest acute toxicity of pesticide residues, we were able to associate pollen from the plant genus Spiraea L. (Rosales: Rosaceae) with extraordinarily high concentrations of thiamethoxam and clothianidin, and also with high concentrations of acephate and its metabolite methamidophos. This study is the first to trace highly toxic pollen collected by honey bees to a single plant genus. This method of tracking high toxicity pollen samples back to potential source plants could identify additional high-risk combinations of pesticide application methods and timing, movement into pollen, and attractiveness to bees that would be difficult to identify through modeling each of the contributing factors.