Statement of problem and methods employed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538 Pollen-tube growth in diploid plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pollen-tube growth in tetraploid plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tetraploid...

The pollen of five diploid and two tetraploid guayule (Parthenium argentatum Gray) plants was cultured on nutrient media. It was observed that guayule pollen is released as tetrads of spores which will not ger­ minate on the media unless they are separated into individual pollen grains. For each plant, the results of the germination tests varied with the day and the time of day of the pollen co...

Despite much effort, a robust protocol for in vitro germination of Arabidopsis thaliana pollen has been elusive. Here we show that controlled temperatures, a largely disregarded factor in previous studies, and a simple optimized medium, solidified or liquid, yielded pollen germination rates above 80% and pollen tube lengths of hundreds of microns, with both Columbia and Landsberg erecta (Ler) e...

INTRODUCTION Nowadays, pollen calendars are useful tools for clinical guidance intended for allergy sufferers, because they can be used to prevent and manage allergic respiratory diseases, thus improving the quality of life. OBJECTIVES An aeropalinological study was performed in the city of Funchal with the purpose of establishing a pollen calendar and determining allergic risk, based on a se...

The Asteraceae family is one of the largest families, comprising 67 genera and 264 species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days...

The directional growth of the pollen tube from the stigma to the embryo sac in the ovules is regulated by pollen-pistil interactions based on intercellular communication. Although pollen tube growth is regulated by the cytoplasmic Ca(2+) concentration ([Ca(2+)](cyt)), it is not known whether [Ca(2+)](cyt) is involved in pollen tube guidance and reception. Using Arabidopsis expressing the GFP-ba...

Pollen analysis and AMS radiocarbon dating of a short sediment core from a mire in Veisar (Mazandaran province, N Iran) reveals the late-Holocene vegetation history of the area. High pollen values suggest that Caucasian alder (Alnus subcordata) has been present in the vicinity of the mire throughout the record. Wingnut (Pterocarya fraxinifolia), which was previously abundantly present, shows a ...

Previous genetic studies have revealed that a pollen-specific calmodulin-binding protein, No Pollen Germination 1 (NPG1), is required for pollen germination. However, its mode of action is unknown. Here we report direct interaction of NPG1 with pectate lyase-like proteins (PLLs). A truncated form of AtNPG1 lacking the N-terminal tetratricopeptide repeat 1 (TPR1) failed to interact with PLLs, su...

Larvae and imagos of bees rely exclusively on floral rewards as a food source but host-plant range can vary greatly among bee species. While oligolectic species forage on pollen from a single family of host plants, polylectic bees, such as bumblebees, collect pollen from many families of plants. These polylectic species contend with interspecific variability in essential nutrients of their host...

BACKGROUND The optimal dose (300IR) of a five-grass pollen sublingual immunotherapy tablet in terms of efficacy was previously demonstrated from the first pollen season. OBJECTIVE Here, we aim to confirm whether this dose remained optimal during the peak of the pollen season by assessing the efficacy and quality of life data. METHODS A total of 628 subjects with grass pollen rhinoconjunctiv...