scholarly journals Biochemical composition of Phleum pratense pollen grains: A review

2021 ◽  
Vol 136 ◽  
pp. 98-109
Author(s):  
Nicolas Visez ◽  
Patricia de Nadaï ◽  
Marie Choël ◽  
Jinane Farah ◽  
Mona Hamzé ◽  
...  
Keyword(s):  
Biochemical Composition ◽  
Pollen Grains ◽  
Phleum Pratense

Extractable lipids from Phleum pratense pollen grains and their modifications by ozone exposure

Aerobiologia ◽  
2019 ◽  
Vol 36 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Jinane Farah ◽  
Marie Choël ◽  
Patricia de Nadaï ◽  
Sylvie Gosselin ◽  
Denis Petitprez ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Phleum Pratense ◽  
Ozone Exposure

Reduced seed set in Elytrigia repens caused by allelopathic pollen from Phleum pratense

1995 ◽  
Vol 73 (9) ◽  
pp. 1417-1422 ◽  
Author(s):  
Stephen D. Murphy ◽  
Lonnie W. Aarssen
Keyword(s):  
Seed Set ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Phleum Pratense ◽  
Pollen Extract ◽  
Old Field ◽  
Heterospecific Pollen ◽  
Elytrigia Repens ◽  
The Mean

Earlier studies have shown that extracts from pollen of Phleum pratense reduce pollen germination and seed set in Elytrigia repens (L.) Nevski (Poaceae), but the effect of in situ pollen from P. pratense on seed set in E. repens in the field has not been previously demonstrated. By clipping the inflorescences of P. pratense just prior to flowering, we reduced pollen dispersal in fields at three old-field sites. In adjacent fields at all three sites, P. pratense was allowed to flower unimpeded. In the clipped fields, the mean number of pollen grains of P. pratense per stigma of E. repens was reduced to less than 1 versus 9–10 grains in the unmanipulated fields. Mean percent seed set of E. repens in the clipped fields was approximately 65–70%, whereas in the unmanipulated fields it was approximately 15–20%. In the following year, when no treatments were applied (i.e., P. pratense was allowed to disperse naturally in all fields), mean percent seed set in the same plants of E. repens was uniformly reduced to less than 15% in all fields. Several lines of evidence suggest that this reduction in seed set in E. repens was caused by allelopathic pollen of P. pratense, rather than by physical occlusion: (i) previous studies using extracts of P. pratense pollen elicited similar decreases in seed set in E. repens, and the seed set decreases were nonlinear (i.e., not indicative of displacement); (ii) the number of P. pratense pollen grains on E. repens stigmas needed to cause pollen allelopathy (based on previous pollen extract studies) existed in the unmanipulated fields but not in the clipped fields; and (iii) E. repens pollen outnumbered P. pratense pollen on E. repens stigmas by at least 5:1 (even when P. pratense inflorescences were not clipped). Key words: competition, Elytrigia repens, heterospecific pollen transfer, Phleum pratense, pollen allelopathy, reproductive success.

Influence of Phleum pratense pollen grains rupture on lipids extraction

Aerobiologia ◽  
2020 ◽  
Vol 36 (4) ◽  
pp. 683-695
Author(s):  
Jinane Farah ◽  
Marie Choël ◽  
Patricia de Nadaï ◽  
Joanne Balsamelli ◽  
Sylvie Gosselin ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Phleum Pratense

Quantification of arteriolar density and embolization by microspheres in rat myocardium

1988 ◽  
Vol 254 (4) ◽  
pp. H636-H650 ◽  
Author(s):  
P. A. Wieringa ◽  
H. G. Stassen ◽  
J. D. Laird ◽  
J. A. Spaan
Keyword(s):  
Pollen Grains ◽  
Phleum Pratense ◽  
Control Flow ◽  
Heart Weight ◽  
Polystyrene Microspheres ◽  
Rat Hearts ◽  
Fractional Reduction ◽  
Stabilization Period

We developed a technique for in vitro determination of arteriolar densities. Hearts, obtained from anesthetized rats and perfused by the Langendorff method, were fully dilated with adenosine and were arrested with an elevated potassium concentration. After a stabilization period, the hearts were perfused with a buffered fixative for some minutes to obtain a nonvital vasculature. After fixation, perfusion was switched back to control for some minutes. The hearts were then perfused with a medium containing a low concentration of microspheres: either pollen grains [Urtica dioica (15.4 microns), Betula (23.5 microns), or Phleum pratense (36.5 microns)] or polystyrene microspheres (15 microns). The perfusion was switched back to the standard medium after flow had been reduced to between 83 and 57% of control flow. Microscopic observations of microsections revealed that the percentages of arterioles embolized by one microsphere were 64% for the 15.4-microns, 74% for the 15-microns, 78% for the 23.5-microns, and 72% for the 36.5-microns microspheres. The percentages of arterioles embolized with two microspheres were 20, 15, 15, and 16%, respectively. The arteriolar densities were calculated from the total fractional reduction in coronary flow, the amount of microspheres injected, the wet heart weight, and the degree of occupancy, which corrects for the multiple embolization of the arterioles. The arteriolar densities in the rat hearts were 162.4 +/- 54.9 mg-1 (N = 6) for polystyrene microspheres of 15 microns, 161.5 +/- 81.1 mg-1 (N = 15) for 15.4-microns microspheres, 31.6 +/- 7.8 mg-1 (N = 9) for 23.5-microns microspheres, and 13.0 +/- 2.4 mg-1 (N = 8) for 36.5-microns microspheres.

Resolution of Channels in the Exine by Translocation of Colloidal Iron

1971 ◽  
Vol 29 ◽  
pp. 352-353
Author(s):  
John R. Rowley
Keyword(s):  
Phosphate Buffer ◽  
Pollen Development ◽  
Osmium Tetroxide ◽  
Pollen Grains ◽  
Deionized Water ◽  
Colloidal Iron ◽  
Fixed Material ◽  
Epilobium Angustifolium ◽  
Untreated Material ◽  
Microspore Mitosis

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.

Freeze-substitution of rye grass and ragweed pollen grains

1990 ◽  
Vol 48 (3) ◽  
pp. 686-687
Author(s):  
Liza B. Martinez ◽  
Susan M. Wick
Keyword(s):  
Cell Function ◽  
Pollen Grains ◽  
Freeze Substitution ◽  
Cell Types ◽  
Rapid Freezing ◽  
Rye Grass ◽  
Acrylic Resins ◽  
Allergenic Proteins ◽  
Cold Embedding ◽  
Structural Preservation

Rapid freezing and freeze-substitution have been employed as alternatives to chemical fixation because of the improved structural preservation obtained in various cell types. This has been attributed to biomolecular immobilization derived from the extremely rapid arrest of cell function. These methods allow the elimination of conventionally used fixatives, which may have denaturing or “masking” effects on proteins. Thus, this makes them ideal techniques for immunocytochemistry, in which preservation of both ultrastructure and antigenicity are important. These procedures are also compatible with cold embedding acrylic resins which are known to increase sensitivity in immunolabelling.This study reveals how rapid freezing and freeze-substitution may prove to be useful in the study of the mobile allergenic proteins of rye grass and ragweed. Most studies have relied on the use of osmium tetroxide to achieve the necessary ultrastructural detail in pollen whereas those that omitted it have had to contend with poor overall preservation.

Formation of botanical composition of clover cereal and alfalfa cereal crops agrophytocenoses depending on sowing method

2020 ◽  
pp. 160-168
Author(s):  
I. Senyk
Keyword(s):  
Festuca Arundinacea ◽  
Global Climate ◽  
Phleum Pratense ◽  
Grass Species ◽  
Cereal Crops ◽  
Forest Steppe ◽  
Botanical Composition ◽  
Cross Sectional ◽  
Row Crops ◽  
Adverse Weather

Botanical composition of grasses is one of the most important indicators the biological value and quality of the obtained hay and pasture forage, the longevity of hayfi elds and pastures depend on. The issue of changing the botanical composition of agrophytocenoses is especially important in the context of global climate change, which in recent decades is also manifested in the territory of Ukraine, as it is possible to establish the most adapted species of legumes and cereals to adverse weather conditions and to identify eff ective technological methods of managing these processes for maximum conservation economically valuable species in the herbage. The purpose of the research is to establish the infl uence of diff erent ways of sowing of clover and alfalfa cereal crops agrophytocenoses on the formation of their botanical composition. Field studies have established diff erent eff ects of conventional in-line, cross-section and cross-sectional methods of sowing on the formation of botanical composition of grass mixtures of clover meadow (Trifolium pratense) varieties Sparta and Pavlyna with timothy meadow (Phleum pratense) and fenugreek multifl oral (Lolium multifl orum) and of agrophytocenoses of alfalfa of Sinyukha and Seraphima sowing varieties with reed fire (Festuca arundinacea Schreb) and middle wheatgrass (Elytrigia intermedia). For the average of four years of life of clover and alfalfa cereal crops agrophytocenoses, the highest proportion of legume component was observed with split-cross sowing – 51.6 % for Sparta, 53.1 % for Pavlyna, 60.3 % for Seraphima and 61.6 % for the Sinyukha variety. In the fourth year of life (the third year of use) of sowed leguminous-cereals agrophytocenoses, the preservation of the legume component was 14.6–15.5 % in clover-cereals grass mixtures with the Sparta variety and 16.0–16.8 % with the Pavlyna variety. In alfalfa grasslands, these indicators were 54.0–55.1 % with Seraphim and 55.0–56.2 % with Sinyukha. Among the studied varieties of clover meadow and alfalfa sowing proved better in the conditions of the Forest Steppe of western Pavlyna and Sinyukha. Cross-sectional and divided cross-sectional sowing of legumes and cereals mixtures proved to be better compared to conventional row crops in terms of conservation of economically valuable grass species. Key words: agrophytocenosis, botanical composition, clover meadow, alfalfa sowing, sowing methods.

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