Sexual reproduction in plants requires elongation of the pollen tube through the transmitting tissues toward the ovary. Tube growth rate is a major determinant of pollen competitive ability. We report that a K(+) channel of the Shaker family in Arabidopsis, SPIK, plays an important role in pollen tube development. SPIK was found to be specifically expressed in pollen. When SPIK was heterologous...

Calmodulin (CaM), a ubiquitous multifunctional calcium sensor in all eukaryotes, mediates calcium action by regulating the activity/function of many unrelated proteins. Although calcium and CaM are known to play a crucial role in pollen germination and pollen tube growth, the proteins that mediate their action have not been identified. We isolated three closely related CaM-binding proteins (NPG...

Aim To understand better the representation of arctic tundra vegetation by pollen data, we analysed pollen assemblages and pollen accumulation rates (PARs) in the surface sediments of lakes. Location Modern sediment samples were collected from seventy-eight lakes located in the Arctic Foothills and Arctic Coastal Plain regions of northern Alaska. Methods For seventy of the lakes, we analysed po...

Pollen allergies have been rapidly increasing over the last decades. Many allergenic proteins and non-allergenic adjuvant compounds of pollen are involved in the plant defense against environmental or microbial stress. The first aim of this study was to analyze and compare the colonizing microbes on allergenic pollen. The second aim was to investigate detectable correlations between pollen micr...

Pollen grains from grasses using the C3 and C4 photosynthetic pathways have distinct ranges of d C values that may be used to estimate their relative abundance in paleorecords. We evaluated a spooling-wire microcombustion device interfaced with an isotope-ratio mass spectrometer (SWiM-IRMS) for dC analysis of individual grass-pollen grains. Pollen from four C3 and four C4 grass species was isol...

1. introduction the zagros mountains present a great potential for paleo-environmental studies for the reconstruction climates of the late-pleistocene and holocene. iranian zagros mountains form the northeastern boundary of the fertile crescent and separating the mesopotamian lowlands from the iranian plateau. it is postulated that near east was a place for the domestication of plants and anima...

The Neotropical genus Heliconius (Nymphalidae) is unique among butterflies for its pollen-feeding behaviour. With the application of saliva, they extract amino acids from pollen grains on the outside of the proboscis. We predicted that the salivary glands of pollen-feeding Heliconiinae would show adaptations to this derived feeding behaviour. A biometrical analysis of the salivary glands reveal...

Pollen-stigma interactions are essential for pollen germination. The highly regulated process of pollen germination includes pollen adhesion, hydration, and germination on the stigma. However, the internal signaling of pollen that regulates pollen-stigma interactions is poorly understood. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex which plays important roles ...