نتایج جستجو برای: pollen quantity
تعداد نتایج: 102475 فیلتر نتایج به سال:
In this research, plant morphology and pollen micromorphology of 14 populations of 3 species belonging to two sections Plethiosphace and Hemisphace of Salvia genus in Iran were studied. In the morphological study 25 quantitative and qualitative characters were investigated and the results clearly separated the species into two groups. The pollen grains from the herbarium specimens were prepared...
Flowers of cultivated buckwheat (Fagopyrum esculentum Moench) often receive natural pollen loads of fewer than 10 pollen grains. The cultivated varieties also have high genetic variability. These observations raise the question of whether seed production in buckwheat is often limited by pollen delivery, and whether small increases in pollen load could result in gametophytic selection through po...
the present research was conducted to determine the percent self-incompatibility in some asian pear (pyrus serotina rehd.) as well in european pear (pyrus communis l.) cultivars. the experiment was carried out during 2006 and 2007 growing seasons. pollen grains were collected and tested for viability using in-vitro pollen culture. for microscopic examination of pollen tube growth in the style, ...
Nonea Medik. is a genus of the Boraginaceae tribe Boragineae, with approximately 35 species worldwide. Examination of their palynological characters supported the separation of taxa, which is usually based on morphological and micromorphological reproductive features. Pollen grains of 10 taxa representing three groups of taxa in Iran, the N. caspica group, the N. persica group and the N. lutea ...
The aim of this study was to determine the effects of different plant growth regulators, NAA (0 mg/l, 50 mg/l and 100 mg/l) and GA3 (0 mg/l, 50 mg/l and 100 mg/l), with various boron concentrations (0 mg/l, 50 mg/l and 100 mg/l) on pollen germination of ‘Şaba’, ‘Rabie’ and ‘Padre’ almond cultivars in 10% sucrose and 1% agar medium at 24°C in dark conditions. The results showed that different tr...
Intraspecific variation in pollen deposition and number of pollen tubes per style is rarely quantified, but is essential for assessing the occurrence of pollen limitation and pollen competition and their evolutionary implications. Moreover, pollen deposition, pollen tube growth, and the fate of fertilized ovules are rarely distinguished in field studies. Here we present such a study in eight na...
BACKGROUND In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect tax...
Background: Allergy is a clinical disorder affecting the human population with wide geographical distribution. Platanus orientalis (P. orientalis) trees are planted in many countries and their pollen causes allergic reactions. Cyclophilin has recently been identified as one of the most important allergens of P. orientalis pollen. We aimed to clone and purify this allergen in Escherichia coli...
In a study during the 1993 grass pollen season at Leiden, the relationship between atmospheric pollen allergen carried by five size fractions of pauci-micronic (few microns) particles and the grass pollen count was investigated. Sampling was carried out on dry days, and atmospheric pollen allergen in the particle fractions was assessed by a RAST-inhibition assay while grass pollen quantities we...
The regulation of protein collection through pollen foraging plays an important role in pollination and in the life of bee colonies that adjust their foraging to natural variation in pollen protein quality and temporal availability. Bumble bees occupy a wide range of habitats from the Nearctic to the Tropics in which they play an important role as pollinators. However, little is known about how...
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