Various mechanisms in flowering plants have evolved to prevent the tendency of self-fertilization created by close proximity of male and female reproductive organs in a perfect flower. One such mechanism, called self-incompatibility (SI), allows the pistil of a plant to reject self pollen or pollen from genetically related individuals, thus preventing inbreeding and promoting outcrosses. Geneti...

Brassinosteroids represent a class of plant hormones with high-growth promoting activity. They are found at low levels in pollen, anthers, seeds, leaves, stems, roots, flowers, grain, and young vegetative tissues throughout the plant kingdom. Brassinosteroids are a family of about 60 phytosteroids. The article gives a comprehensive survey on the hitherto known brassinosteroids isolated from pla...

The generative cell wall in the pollen grain of Endymion non-scriptus is formed, as in somatic cells, from a cell plate between the vegetative and generative nuclei. This wall curves around the generative nucleus, and fuses with the intine to enclose the generative cell. The generative cell is subsequently freed from the intine by the constriction of the generative cell wall between the generat...

Pollen grains of Malvoideae (Malvaceae) which corbiculate bees cannot collect constitute a floral filter that excludes pollen-collecting bumble and honey from exploiting pollen resources. Although large, spiny are in fact harder to compact for collection by bees, morphology (e.g., grain diameter, spine length) is not itself reliable indicator collectability. In this study, we discovered two spe...

Leucine-rich repeat extensins (LRXs) are chimeric proteins containing an N-terminal leucine-rich repeat (LRR) and a C-terminal extensin domain. LRXs are involved in cell wall formation in vegetative tissues and required for plant growth. However, the nature of their role in these cellular processes remains to be elucidated. Here, we used a combination of molecular techniques, light microscopy, ...

For what we believe to be the first time, digital holographic microscopy is applied to perform optical diffraction tomography of a pollen grain. Transmission phase images with nanometric axial accuracy are numerically reconstructed from holograms acquired for different orientations of the rotating sample; then the three-dimensional refractive index spatial distribution is computed by inverse ra...

BACKGROUND : Grass pollen grain, an important aeroallergen, can disperse in the environment pollen cytoplasmic granules (PCGs) able to release water-soluble allergens when they are washed out by rainfall. The allergenicity of these washed PCGs is, however, preserved. OBJECTIVE : The purpose of the study was to assess the allergenic potential of washed and unwashed PCGs, from Phleum pratense p...