scholarly journals Contribution of pollen to atmospheric ice nuclei concentrations

2014 ◽  
Vol 14 (11) ◽  
pp. 5433-5449 ◽  
Author(s):  
J. D. Hader ◽  
T. P. Wright ◽  
M. D. Petters
Keyword(s):  
North Carolina ◽  
Fold Increase ◽  
Pollen Grain ◽  
Background Concentrations ◽  
Grain Number ◽  
Wetting And Drying ◽  
Ice Nuclei ◽  
Southeastern Us ◽  
Maximum Value ◽  
Pollen Types

Abstract. Recent studies have suggested that the ice-nucleating ability of some types of pollen is derived from non-proteinaceous macromolecules. These macromolecules may become dispersed by the rupturing of the pollen grain during wetting and drying cycles in the atmosphere. If true, this mechanism might prove to be a significant source of ice nuclei (IN) concentrations when pollen is present. Here we test this hypothesis by measuring ambient IN concentrations from the beginning to the end of the 2013 pollen season in Raleigh, North Carolina, USA. Air samples were collected using a swirling aerosol collector twice per week and the solutions were analysed for ice nuclei activity using a droplet freezing assay. Rainwater samples were collected at times when pollen grain number concentrations were near their maximum value and analysed with the drop-freezing assay to compare the potentially enhanced IN concentrations measured near the ground with IN concentrations found aloft. Ambient ice nuclei spectra, defined as the number of ice nuclei per volume of air as a function of temperature, are inferred from the aerosol collector solutions. No general trend was observed between ambient pollen grain counts and observed IN concentrations, suggesting that ice nuclei multiplication via pollen grain rupturing and subsequent release of macromolecules was not prevalent for the pollen types and meteorological conditions typically encountered in the southeastern US. A serendipitously sampled collection after a downpour provided evidence for a rain-induced IN burst with an observed IN concentration of approximately 30 per litre, a 30-fold increase over background concentrations at −20 °C. The onset temperature of freezing for these particles was approximately −12 °C, suggesting that the ice-nucleating particles were biological in origin.

scholarly journals Contribution of pollen to atmospheric ice nuclei concentrations

2013 ◽  
Vol 13 (12) ◽  
pp. 31673-31712 ◽  
Author(s):  
J. D. Hader ◽  
T. P. Wright ◽  
M. D. Petters
Keyword(s):  
North Carolina ◽  
Pollen Season ◽  
General Trend ◽  
Fold Increase ◽  
Background Concentrations ◽  
Wetting And Drying ◽  
Ice Nuclei ◽  
Feedback Cycle ◽  
Southeastern Us ◽  
Pollen Types

Abstract. Recent studies have suggested that the ice nucleating ability of some types of pollen is derived from non-proteinaceous macromolecules. These macromolecules may become dispersed by the rupturing of the pollen sac during wetting and drying cycles in the atmosphere. If true, this mechanism might prove to be a significant source of ice nuclei (IN) concentrations when pollen are present. Here we test this hypothesis by measuring ambient IN concentrations from the beginning to the end of the 2013 pollen season in Raleigh, North Carolina, USA. Air samples were collected using a swirling aerosol collector twice per week and the solutions were analysed for ice nuclei activity using a droplet freezing assay. Rainwater samples were collected at the peak of the pollen season and analysed with the drop freezing assay to compare the potentially enhanced IN concentrations measured near the ground with IN concentrations found aloft. Ambient ice nuclei spectra, defined as the number of ice nuclei per volume of air as a function of temperature, are inferred from the aerosol collector solutions. No general trend was observed between ambient pollen counts and observed IN concentrations, suggesting that ice nuclei multiplication via pollen sac rupturing and subsequent release of macromolecules was not prevalent for the pollen types and meteorological conditions typically encountered in the Southeastern US. A serendipitously sampled collection after a downpour provided evidence for a rain-induced IN burst with an observed IN concentration of approximately 30 per litre, a 30-fold increase over background concentrations at −20 °C. The onset temperature of freezing for these particles was approximately −12 °C, suggesting that the ice nucleating particles were biological in origin. The magnitude of the IN burst was significantly larger than previously observed, providing additional evidence to merit further investigation of a self-regulated feedback cycle between the atmosphere and biosphere via the release of cloud forming particles in rain forest environments.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals 155. Infective Endocarditis and Cardiac Valve Surgery During the Opioid Epidemic in North Carolina, 2007 to 2017

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S12-S12
Author(s):  
Asher Schranz ◽  
Aaron Fleischauer ◽  
Vivian H Chu ◽  
David Rosen
Keyword(s):  
North Carolina ◽  
Infective Endocarditis ◽  
Drug Use ◽  
Fold Increase ◽  
International Classification Of Diseases ◽  
Valve Surgery ◽  
Cardiac Valve ◽  
Hospital Charges ◽  
Opioid Epidemic ◽  
Cardiac Valve Surgery

Abstract Background Infective endocarditis (IE) associated with drug use (DA-IE) is rising nationally. North Carolina (NC), a state hard-hit by the opioid epidemic, saw an over 12-fold increase in DA-IE from 2010 to 2015. Concerns about surgery exist due to the risk of ongoing drug use and reinfection after valvuloplasty. We evaluated trends, characteristics, and outcomes of valve surgery for DA-IE, compared with IE not associated with drug use (non-DA-IE), in NC. Methods We analyzed the NC Discharge Database, which includes administrative data from all hospital discharges in NC. Using International Classification of Diseases codes, we identified all persons ≥18 years of age with IE from July 1, 2007 to June 30, 2017. Hospitalizations were deemed DA-IE by a diagnosis code related to illicit drug use, dependence, poisoning or withdrawal (excepting marijuana), or Hepatitis C in a person born after 1965. All others were labeled non-DA-IE. Procedure codes were queried to identify cardiac valve surgery. Year-to-year trends in surgery for IE by drug-associated status were reported. Demographics, length of stay (LOS), charges, and disposition were compared among DA-IE and non-DA-IE. Results A total of 22,809 hospitalizations were coded for IE. Valve surgery occurred in 1,652. Of surgical hospitalizations, 17% overall and 42% in the final study year were DA-IE. Hospitalizations for DA-IE where surgery was done increased from <10 through 2012–2013 to 109 in 2016–2017 (figure). Compared with non-DA-IE, those undergoing surgery for DA-IE were younger (median age 33 vs. 56), female (47% vs. 33%), White (89% vs. 64%), uninsured (34% vs. 11%), insured by Medicaid (39% vs. 13%), and had tricuspid valve surgery (38% vs. 11%). DA-IE had longer median LOS (27 vs. 17 days) and were less often discharged home (51% vs. 59%). For the 287 DA-IE admissions with surgery, median hospital charges were $247,524, totaling over $79,000,000. All comparisons were significant at P < 0.0001. Conclusion From 2007 to 2017, valve surgeries for DA-IE in NC rose over tenfold and are approaching half of all surgeries for IE. This phenomenon is an underappreciated and morbid component of the opioid epidemic that burdens hospital and state resources. Research into best practices for managing patients with DA-IE and addressing addiction in this setting is critically needed. Disclosures All authors: No reported disclosures.

scholarly journals Precise Pollen Grain Detection in Bright Field Microscopy Using Deep Learning Techniques

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3583 ◽  
Author(s):  
Ramón Gallardo-Caballero ◽  
Carlos J. García-Orellana ◽  
Antonio García-Manso ◽  
Horacio M. González-Velasco ◽  
Rafael Tormo-Molina ◽  
...  
Keyword(s):  
Network Architecture ◽  
Detection System ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Average Value ◽  
Pollen Types ◽  
Pollen Concentrations ◽  
Pollen Counting ◽  
Estimation System ◽  
3D Information

The determination of daily concentrations of atmospheric pollen is important in the medical and biological fields. Obtaining pollen concentrations is a complex and time-consuming task for specialized personnel. The automatic location of pollen grains is a handicap due to the high complexity of the images to be processed, with polymorphic and clumped pollen grains, dust, or debris. The purpose of this study is to analyze the feasibility of implementing a reliable pollen grain detection system based on a convolutional neural network architecture, which will be used later as a critical part of an automated pollen concentration estimation system. We used a training set of 251 videos to train our system. As the videos record the process of focusing the samples, this system makes use of the 3D information presented by several focal planes. Besides, a separate set of 135 videos (containing 1234 pollen grains of 11 pollen types) was used to evaluate detection performance. The results are promising in detection (98.54% of recall and 99.75% of precision) and location accuracy (0.89 IoU as the average value). These results suggest that this technique can provide a reliable basis for the development of an automated pollen counting system.

Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain

Weed Science ◽  
2020 ◽  
Vol 68 (6) ◽  
pp. 582-593
Author(s):  
Denis J. Mahoney ◽  
David L. Jordan ◽  
Nilda Roma-Burgos ◽  
Katherine M. Jennings ◽  
Ramon G. Leon ◽  
...  
Keyword(s):  
North Carolina ◽  
Dose Response ◽  
Coastal Plain ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Fold Increase ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Sites Of Action ◽  
Two Populations

AbstractPalmer amaranth (Amaranthus palmeri S. Watson) populations resistant to acetolactate synthase (ALS)-inhibiting herbicides and glyphosate are fairly common throughout the state of North Carolina (NC). This has led farm managers to rely more heavily on herbicides with other sites of action (SOA) for A. palmeri control, especially protoporphyrinogen oxidase and glutamine synthetase inhibitors. In the fall of 2016, seeds from A. palmeri populations were collected from the NC Coastal Plain, the state’s most prominent agricultural region. In separate experiments, plants with 2 to 4 leaves from the 110 populations were treated with field use rates of glyphosate, glufosinate-ammonium, fomesafen, mesotrione, or thifensulfuron-methyl. Percent visible control and survival were evaluated 3 wk after treatment. Survival frequencies were highest following glyphosate (99%) or thifensulfuron-methyl (96%) treatment. Known mutations conferring resistance to ALS inhibitors were found in populations surviving thifensulfuron-methyl application (Ala-122-Ser, Pro-197-Ser, Trp-574-Leu, and/or Ser-653-Asn), in addition to a new mutation (Ala-282-Asp) that requires further investigation. Forty-two populations had survivors after mesotrione application, with one population having 17% survival. Four populations survived fomesafen treatment, while none survived glufosinate. Dose–response studies showed an increase in fomesafen needed to kill 50% of two populations (LD50); however, these rates were far below the field use rate (less than 5 g ha−1). In two populations following mesotrione dose–response studies, a 2.4- to 3.3-fold increase was noted, with LD90 values approaching the field use rate (72.8 and 89.8 g ha−1). Screening of the progeny of individuals surviving mesotrione confirmed the presence of resistance alleles, as there were a higher number of survivors at the 1X rate compared with the parent population, confirming resistance to mesotrione. These data suggest A. palmeri resistant to chemistries other than glyphosate and thifensulfuron-methyl are present in NC, which highlights the need for weed management approaches to mitigate the evolution and spread of herbicide-resistant populations.

scholarly journals Sorghum MSD3 Encodes an ω-3 Fatty Acid Desaturase that Increases Grain Number by Reducing Jasmonic Acid Levels

2019 ◽  
Vol 20 (21) ◽  
pp. 5359 ◽  
Author(s):  
Lavanya Dampanaboina ◽  
Yinping Jiao ◽  
Junping Chen ◽  
Nicholas Gladman ◽  
Ratan Chopra ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Jasmonic Acid ◽  
Linolenic Acid ◽  
Sequence Data ◽  
Fatty Acid Desaturase ◽  
Fold Increase ◽  
Cereal Crops ◽  
Grain Number ◽  
Genomic Editing ◽  
Grain Number Per Panicle

Grain number per panicle is an important component of grain yield in sorghum (Sorghum bicolor (L.)) and other cereal crops. Previously, we reported that mutations in multi-seeded 1 (MSD1) and MSD2 genes result in a two-fold increase in grain number per panicle due to the restoration of the fertility of the pedicellate spikelets, which invariably abort in natural sorghum accessions. Here, we report the identification of another gene, MSD3, which is also involved in the regulation of grain numbers in sorghum. Four bulked F2 populations from crosses between BTx623 and each of the independent msd mutants p6, p14, p21, and p24 were sequenced to 20× coverage of the whole genome on a HiSeq 2000 system. Bioinformatic analyses of the sequence data showed that one gene, Sorbi_3001G407600, harbored homozygous mutations in all four populations. This gene encodes a plastidial ω-3 fatty acid desaturase that catalyzes the conversion of linoleic acid (18:2) to linolenic acid (18:3), a substrate for jasmonic acid (JA) biosynthesis. The msd3 mutants had reduced levels of linolenic acid in both leaves and developing panicles that in turn decreased the levels of JA. Furthermore, the msd3 panicle phenotype was reversed by treatment with methyl-JA (MeJA). Our characterization of MSD1, MSD2, and now MSD3 demonstrates that JA-regulated processes are critical to the msd phenotype. The identification of the MSD3 gene reveals a new target that could be manipulated to increase grain number per panicle in sorghum, and potentially other cereal crops, through the genomic editing of MSD3 functional orthologs.

scholarly journals Pollen grain number and viability contribute to variation in effective ovule number among oilseed rape genotypes

Euphytica ◽  
2021 ◽  
Vol 218 (1) ◽  
Author(s):  
Xiao Guo ◽  
Bao-Luo Ma ◽  
Neil B. McLaughlin ◽  
Yajun Gao ◽  
Xiaoming Wu ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Pollen Grain ◽  
Grain Number ◽  
Ovule Number

Migration of Lanthanum Through the Pollen Exine

1970 ◽  
Vol 28 ◽  
pp. 298-299
Author(s):  
John R. Rowley ◽  
James J. Flynn
Keyword(s):  
High Vacuum ◽  
Pollen Grain ◽  
Pollen Exine ◽  
Pollen Types ◽  
Independent Existence ◽  
Vacuum Storage

Evolutionists have considered the exine as a defense against desiccation during the independent existence of the pollen grain. While a certain level of waterproofing may have been important to plants in their assumption of the terrestrial habit, two characteristics of some contemporary pollen types are inconsistent with the waterproofing idea: 1) some wind pollinated pollen types lack a continuous exine and 2) the pollen protoplasts can survive a high vacuum and subsequently germinate-vacuum storage can even prolong the period of viability.

Addition of rye chromosome 4R to wheat increases anther length and pollen grain number

2015 ◽  
Vol 128 (5) ◽  
pp. 953-964 ◽  
Author(s):  
Vy Nguyen ◽  
Delphine Fleury ◽  
Andy Timmins ◽  
Hamid Laga ◽  
Matthew Hayden ◽  
...  
Keyword(s):  
Pollen Grain ◽  
Grain Number ◽  
Anther Length

The importance of being the first pollen in the strobili of Scots pine

2008 ◽  
Vol 38 (12) ◽  
pp. 2976-2980 ◽  
Author(s):  
Saila Varis ◽  
Arja Santanen ◽  
Anne Pakkanen ◽  
Pertti Pulkkinen
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Pollen Grain ◽  
Seed Orchards ◽  
Pollination Experiments ◽  
Seed Crop ◽  
Pollen Types ◽  
Pine Pollen

Timing of pollen arrival may affect the level of seeds fertilized by pollen from outside seed orchards, especially in seed orchards of Scots pine ( Pinus sylvestris L.) established in southern Finland with stock from northern populations. We performed sequential pollination experiments with Scots pine pollen collected from seed orchard clones originating from southern and northern Finland and recipient strobili in clones originating from southern Finland. When southern pollen was introduced first, seeds were sired equally by northern and southern genotypes. When northern pollen was introduced first, northern genotypes were found in 75% of the resulting seeds. When both pollen types were introduced at the same time, the resulting seed crop was split almost equally between northern and southern genotypes. These results do not unconditionally support the idea that the first pollen grain in the pollen chamber always fertilizes the ovum; instead, they suggest a more complex way of competition between pollen grains.

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