The role of honeybees in pollination of apples

1970 ◽  
Vol 10 (44) ◽  
pp. 366 ◽  
Author(s):  
DF Langridge ◽  
PT Jenkins
Keyword(s):  
Flowering Time ◽  
Fruit Set ◽  
Major Effect ◽  
Flight Activity ◽  
Ambient Conditions ◽  
Early Afternoon ◽  
Pollen Concentrations ◽  
High Concentrations ◽  
Number Of Seeds

Considering the relatively high concentrations of airborne apple pollen in apple orchards at flowering time, the present study was undertaken to determine the relative roles of airborne and insect borne pollen in the pollination of apples. Enclosing trees of Yates apples, each grafted with a limb of Jonathan, in bee-proof cages caused significant reduction in the number of fruit set, the weight of fruit harvested, and the number of seeds per Fruit as compared with uncaged trees, although airborne apple pollen concentrations were 4.07 times higher inside the cages than outside. Concentrations of airborne apple pollen are greatest in late morning and early afternoon. Flight activity of bees was related to ambient conditions, temperature having a major effect. There appears to be a threshold of flight activity in the region of 13�C. Ripening and dehiscence of anthers of Yates apple are promoted by higher temperatures and lower humidities.

The role of honeybees in pollination of cherries

1973 ◽  
Vol 13 (61) ◽  
pp. 193 ◽  
Author(s):  
DF Langridge ◽  
RD Goodman
Keyword(s):  
Airborne Pollen ◽  
Flight Activity ◽  
Ambient Temperatures ◽  
Pollen Concentrations ◽  
Cherry Orchard ◽  
Marked Decline

The availability of pollen for fertilization of Moss' Early cherries and its dispersal by wind and by honeybees was studied in the laboratory and in a cherry orchard. Ripening and dehiscence of anthers was promoted by higher temperatures and lower relative humidities. Airborne pollen concentrations in the orchard were greater between 10.00 a.m. and 4.00 p.m. than during the remainder of the day. Flight activity of bees was related to ambient temperatures and bee visits to cherry flowers were comparable with those for apples. Enclosing trees in beeproof cages caused a marked decline in fruit yields.

scholarly journals From Homogeneous to Heterogenized Molecular Catalysts for H2 Production by Formic Acid Dehydrogenation: Mechanistic Aspects, Role of Additives, and Co-Catalysts

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 733 ◽  
Author(s):  
Panagiota Stathi ◽  
Maria Solakidou ◽  
Maria Louloudi ◽  
Yiannis Deligiannakis
Keyword(s):  
Formic Acid ◽  
Sodium Formate ◽  
H2 Production ◽  
Ambient Conditions ◽  
Co Catalysts ◽  
High Concentrations ◽  
Formic Acid Dehydrogenation ◽  
Key Steps ◽  
Molecular Catalysts

H2 production via dehydrogenation of formic acid (HCOOH, FA), sodium formate (HCOONa, SF), or their mixtures, at near-ambient conditions, T < 100 °C, P = 1 bar, is intensively pursued, in the context of the most economically and environmentally eligible technologies. Herein we discuss molecular catalysts (ML), consisting of a metal center (M, e.g., Ru, Ir, Fe, Co) and an appropriate ligand (L), which exemplify highly efficient Turnover Numbers (TONs) and Turnover Frequencies (TOFs) in H2 production from FA/SF. Typically, many of these ML catalysts require the presence of a cofactor that promotes their optimal cycling. Thus, we distinguish the concept of such cofactors in additives vs. co-catalysts: When used at high concentrations, that is stoichiometric amounts vs. the substrate (HCOONa, SF), the cofactors are sacrificial additives. In contrast, co-catalysts are used at much lower concentrations, that is at stoichiometric amount vs. the catalyst. The first part of the present review article discusses the mechanistic key steps and key controversies in the literature, taking into account theoretical modeling data. Then, in the second part, the role of additives and co-catalysts as well as the role of the solvent and the eventual inhibitory role of H2O are discussed in connection to the main mechanistic steps. For completeness, photons used as activators of ML catalysts are also discussed in the context of co-catalysts. In the third part, we discuss examples of promising hybrid nanocatalysts, consisting of a molecular catalyst ML attached on the surface of a nanoparticle. In the same context, we discuss nanoparticulate co-catalysts and hybrid co-catalysts, consisting of catalyst attached on the surface of a nanoparticle, and their role in the performance of molecular catalysts ML.

scholarly journals Honey bee as an effective pollinating agent of pumpkin

2009 ◽  
Vol 66 (4) ◽  
pp. 476-480 ◽  
Author(s):  
Daniel Nicodemo ◽  
Regina Helena Nogueira Couto ◽  
Euclides Braga Malheiros ◽  
David De Jong
Keyword(s):  
Fruit Set ◽  
Fruit Size ◽  
No Production ◽  
Diabrotica Speciosa ◽  
Number Of Visits ◽  
Male Flowers ◽  
Mean Time ◽  
Number Of Seeds ◽  
Female Flowers

The production of fruits and seeds of many crops is increased when bees visit their flowers pollinating them. The aim of this research was to study the pollination of pumpkins (Cucurbita maxima Duch. var. Exposição), to determine the diversity of insects visiting its flowers, the time and type of provision obtained and the effect of the visits on fruit set, fruit size and weight, and number of seeds. Apis mellifera L. accounted for 73.4% of the visits made by bees, collecting pollen during 34.5 s per flower and nectar in 43.9 s and 29.3 s from female and male flowers, respectively. Trigona spinipes (Fabr.) collected only nectar, during a mean time of 60.5 s per flower, and represented 26.6% of the visits by bees. Diabrotica speciosa (Germ.) only fed on the petals of the flower. When no insect visits occurred, there was no production of fruits. In the flowers with free visitation by insects, fruit set was 40%. The higher the number of visits, up to 16, by A. mellifera to female flowers, the greater was the fruit set, fruit size and weight, and number of seeds. In flowers visited by insects from the onset of anthesis until 9 a.m., fruit set was 35%. After 9 a.m., there was no fruit set, demonstrating the important role of A. mellifera as a pollinating agent of pumpkin, since it was the only insect visiting up to 9 a.m.

scholarly journals Hypoxia and Mitochondrial Dysfunction in Pregnancy Complications

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 405 ◽  
Author(s):  
Xiang-Qun Hu ◽  
Lubo Zhang
Keyword(s):  
Pregnancy Complications ◽  
Intrauterine Growth Restriction ◽  
Animal Studies ◽  
Major Effect ◽  
Causative Role ◽  
Therapeutic Approaches ◽  
Maternal Complications ◽  
Mitochondrial Ros ◽  
Subsequent Risk

Hypoxia is a common and severe stress to an organism’s homeostatic mechanisms, and hypoxia during gestation is associated with significantly increased incidence of maternal complications of preeclampsia, adversely impacting on the fetal development and subsequent risk for cardiovascular and metabolic disease. Human and animal studies have revealed a causative role of increased uterine vascular resistance and placental hypoxia in preeclampsia and fetal/intrauterine growth restriction (FGR/IUGR) associated with gestational hypoxia. Gestational hypoxia has a major effect on mitochondria of uteroplacental cells to overproduce reactive oxygen species (ROS), leading to oxidative stress. Excess mitochondrial ROS in turn cause uteroplacental dysfunction by damaging cellular macromolecules, which underlies the pathogenesis of preeclampsia and FGR. In this article, we review the current understanding of hypoxia-induced mitochondrial ROS and their role in placental dysfunction and the pathogenesis of pregnancy complications. In addition, therapeutic approaches selectively targeting mitochondrial ROS in the placental cells are discussed.

scholarly journals A novel deletion in FLOWERING LOCUS T modulates flowering time in winter oilseed rape

2021 ◽  
Author(s):  
Paul Vollrath ◽  
Harmeet S. Chawla ◽  
Sarah V. Schiessl ◽  
Iulian Gabur ◽  
HueyTyng Lee ◽  
...  
Keyword(s):  
Association Mapping ◽  
Flowering Time ◽  
Oilseed Rape ◽  
Major Effect ◽  
Structural Variants ◽  
Winter Oilseed Rape ◽  
Flowering Locus T ◽  
Winter Type ◽  
Long Read ◽  
Flowering Locus

Abstract Key message A novel structural variant was discovered in the FLOWERING LOCUS T orthologue BnaFT.A02 by long-read sequencing. Nested association mapping in an elite winter oilseed rape population revealed that this 288 bp deletion associates with early flowering, putatively by modification of binding-sites for important flowering regulation genes. Abstract Perfect timing of flowering is crucial for optimal pollination and high seed yield. Extensive previous studies of flowering behavior in Brassica napus (canola, rapeseed) identified mutations in key flowering regulators which differentiate winter, semi-winter and spring ecotypes. However, because these are generally fixed in locally adapted genotypes, they have only limited relevance for fine adjustment of flowering time in elite cultivar gene pools. In crosses between ecotypes, the ecotype-specific major-effect mutations mask minor-effect loci of interest for breeding. Here, we investigated flowering time in a multiparental mapping population derived from seven elite winter oilseed rape cultivars which are fixed for major-effect mutations separating winter-type rapeseed from other ecotypes. Association mapping revealed eight genomic regions on chromosomes A02, C02 and C03 associating with fine modulation of flowering time. Long-read genomic resequencing of the seven parental lines identified seven structural variants coinciding with candidate genes for flowering time within chromosome regions associated with flowering time. Segregation patterns for these variants in the elite multiparental population and a diversity set of winter types using locus-specific assays revealed significant associations with flowering time for three deletions on chromosome A02. One of these was a previously undescribed 288 bp deletion within the second intron of FLOWERING LOCUS T on chromosome A02, emphasizing the advantage of long-read sequencing for detection of structural variants in this size range. Detailed analysis revealed the impact of this specific deletion on flowering-time modulation under extreme environments and varying day lengths in elite, winter-type oilseed rape.

Variation in the morphology and flowering time of cluster clover (Trifolium glomeratum L.) and its relationship to distribution in southern Australia

1995 ◽  
Vol 46 (5) ◽  
pp. 1027 ◽  
Author(s):  
FP Smith ◽  
PS Cocks ◽  
MA Ewing
Keyword(s):  
Genetic Variation ◽  
Flowering Time ◽  
Seed Mass ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Summer Maximum ◽  
Maximum Temperatures ◽  
Pattern Of Variation ◽  
Growth Habits

Cluster clover is a widely distributed and ecologically successful introduced legume in southern Australia. In an attempt to understand the role of genetic variation in this success, morphological and physiological traits were measured in 94 accessions from southern Australia and 6 from the Mediterranean basin. Flowering time ranged from 105 to 185 days after sowing, but was not strongly correlated with annual rainfall or length of growing season at the site of collection. Variation in other traits partitioned the populations into two morphs which, apart from flowering time and leaf marker, were largely homogeneous. The morphs differed significantly in floret number per inflorescence (22 v. 32-37) and seed mass (379 8g v. 523 8g), had different growth habits and strong within-morph associations between leaf markers and stipule and petal coloration. The morphs differed in their distributions within southern Australia and the pattern of distribution was related to summer maximum temperatures, winter minimum temperatures and spring rainfall. These results demonstrate that genetic variation has been important to the success of cluster clover and suggests that the variation is organized. The pattern of variation observed and its relationship to ecogeography is consistent with findings for other highly inbreeding species. A map of the species distribution in Western Australia is presented.

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

Unveiling the Role of Sulfur in Rapid Defluorination of Florfenicol by Sulfidized Nanoscale Zero-Valent Iron in Water under Ambient Conditions

2021 ◽  
Vol 55 (4) ◽  
pp. 2628-2638
Author(s):  
Zhen Cao ◽  
Hao Li ◽  
Gregory V. Lowry ◽  
Xiaoyang Shi ◽  
Xiangcheng Pan ◽  
...  
Keyword(s):  
Zero Valent Iron ◽  
Ambient Conditions ◽  
Nanoscale Zero Valent Iron

Invisible and Intangible, but Undeniable: Role of Ambient Conditions in Building Hotel Guests’ Loyalty

2014 ◽  
Vol 24 (7) ◽  
pp. 727-753 ◽  
Author(s):  
Myoungsun Suh ◽  
Hyoungeun Moon ◽  
Heesup Han ◽  
Sunny Ham
Keyword(s):  
Ambient Conditions
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