نتایج جستجو برای: 5 pollen
تعداد نتایج: 1234887 فیلتر نتایج به سال:
INTRODUCTION An association between pollen count (Poaceae) and symptoms is well known, but to a lesser degree the importance of priming and lag effects. Also, threshold levels for changes in symptom severity need to be validated. The present study aims to investigate the relationship between pollen counts, symptoms and health related quality of life (HRQL), and to validate thresholds levels, us...
Lower plants generate mobile sperm cells that must reach their female counterparts by swimming. This requirement for water is a disadvantage for these plants as compared with angiosperms, for which the dry pollen attaches to a stigma and becomes hydrated, enabling the emerging pollen tube to grow in the protected environment of the pistil. After adhesion, hydration, and germination of the polle...
Pollen viability and its germination capability for fruit set in are almond and peach essential. To optimize the pollen culture medium of almond and peach and selection of best medium, the present study was carried out with 48 different culture media containing different compositions including diverse levels of boric acid (0 and 100mg/1), calcium nitrate (0,150and300mg/l،), magnesium sulphate (...
Low seed yield is a limiting factor for cross breeding and hybrid seed production in cyclamen. This study was performed to investigate pollen germination and its relation to cross-pollination success and fruit set in this plant. In order to achieve a high level of pollen germination, the effect of different concentrations of chemical compounds were examined on in vitro pollen germination of cyc...
To investigate whether the high expression levels of actin-depolymerizing factor genes are related to pollen development, three GhADF genes (cDNAs) were isolated and characterized in cotton. Among them, GhADF6 and GhADF8 were preferentially expressed in petals, whereas GhADF7 displayed the highest level of expression in anthers, revealing its anther specificity. The GhADF7 transcripts in anther...
Although there has been much experimental work on floral traits that are under selection from mutualists and antagonists, selection by abiotic environmental factors on flowers has been largely ignored. Here we test whether pollen susceptibility to rain damage could have played a role in the evolution of the reproductive architecture of Davidia involucrata, an endemic in the mountains of western...
Pollen grains are one of the most important groups of atmospheric biological particles that originate allergic processes. Knowledge of intradiurnal variation of the atmospheric pollen may be useful for the treatment and prevention of pollen allergies. Intradiurnal fluctuation of hourly pollen counts in 24 h are related to the daily rhythm of anther opening, and modified by various interacting f...
BACKGROUND Sublingual immunotherapy (SLIT) is a feasible option to classical subcutaneous immunotherapy to treat respiratory allergy and is increasingly prescribed in Europe. However, the lack of reimbursement may limit its prescription. In 2015, the 5-grass pollen tablets was authorized by the European Medicine Agency to treat grass-pollen induced rhinitis and was approved in Italy for full re...
BACKGROUND Release of cytoplasmic granules from grass pollen upon contact with water is thought to be an important source of airborne allergens. OBJECTIVES To investigate the humoral and cellular responses to intratracheal instillation of Phleum pratense (timothy grass) pollen cytoplasmic granules (PCG) in the Brown Norway rat. METHODS PCG were purified from timothy grass pollen by filtrati...
The suitability of ten diets for the development and reproduction of Franklinothrips orizabensis Johansen, the key natural enemy of Scirtothrips perseae Nakahara, a pest of California grown avocados, was determined in the laboratory. The experimental diets evaluated were: (i) irradiated Ephestia kuehniella Zeller eggs; (ii) irradiated E. kuehniella eggs and avocado pollen; (iii) Tetranychus pac...
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