Pollen ranges from 2.5% to 61% protein content. Most pollen proteins are likely to be enzymes that function during pollen tube growth and subsequent fertilization, but the vast range of protein quantity may not reflect only pollen–pistil interactions. Because numerous vertebrate and invertebrate floral visitors consume pollen for protein, protein content may influence floral host choice. Additi...

Corn (Zea mays L.) that has been genetically engineered to produce the Cry1Ab protein (Bt corn) is resistant to lepidopteran pests. Bt corn is widely planted in the midwestern United States, often adjacent to headwater streams. We show that corn byproducts, such as pollen and detritus, enter headwater streams and are subject to storage, consumption, and transport to downstream water bodies. Lab...

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...

Summary Background. Volumetric pollen traps are commonly used to assess pollen exposure. These traps are well suited for estimating the regional mean airborne pollen concentration but are likely not to provide an accurate index of personal exposure. In this study, we tested the hypothesis that hair sampling may provide different pollen counts from those from pollen traps, especially when the po...

During pollen development each product of meiosis undergoes a stereotypical pattern of cell divisions to give rise to a three-celled gametophyte, the pollen grain. First an asymmetric mitosis generates a larger vegetative cell and a smaller generative cell, then the generative cell undergoes a second mitosis to give rise to two sperm cells. It is unknown how this pattern of cell divisions is co...

Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To si...

Pollen from three S-genotypes of Nicotiana alata was grown in vitro in the presence of S-glycoproteins isolated from styles of the same three genotypes. Pollen germination was not affected by the presence of the S-glycoproteins, but pollen tube growth of all genotypes was inhibited. S2 pollen was preferentially inhibited by the S2-glycoprotein and S3 pollen by the S3-glycoprotein. The S6-glycop...

three different concentrations (10, 20 and 30 ppm) of the dry propolis and pollen extracts were applied in double distilled water. biochemical and hematological parameters in blood of rainbow trout (oncorhynchus mykiss) treated to various propolis and pollen concentrations (10, 20 and 30 ppm) for 96 h were determined.  fish treated to 20 and 30 ppm of propolis extract presented significant incr...

in 2007 and 2008, the influence of pollen source on the shell and kernel traits of resulting seeds and on fruit set was examined to evaluate the potential for xenia or metaxenia in persian walnut. pistillate flowers of ‘jamal’, ‘chandler’, ‘hartley’ and ‘pedro’ were crossed with the pollen of ‘serr’, ‘z60’ and ‘damavand’. the pistillate flowers on each female parent were covered about one week ...

BACKGROUND Beech and oak pollen are potential allergen sources with a world-wide distribution. OBJECTIVE We aimed to characterize the allergen profile of beech and oak pollen and to study cross-reactivities with birch and grass pollen allergens. METHODS Sera from tree pollen-allergic patients with evidence for beech and oak pollen sensitization from Basel, Switzerland, (n=23) and sera from ...