incompatibility in hazelnut (c. avellana l.) is the sporophytic type and under the control of a single s-locus with multiple alleles. compatibility of pollen-stigma in hazelnut is an important consideration in planning crosses in breeding program and in choosing pollinizers for orchard planting. in this study, fluorescence microscopy was used to determination of s-alleles and compatibility rela...

Pollen hydration is usually tightly regulated and occurs in vivo only when desiccated pollen grains acquire water from the female, thus enabling pollen tube growth. Pollen tubes are easily visualized by staining with decolorized aniline blue, a stain specific for callose. We identified a mutant, raring-to-go, in which pollen grains stained for callose before anther dehiscence. When raring-to-go...

In flowering plants, pollen grains germinate to form pollen tubes that transport male gametes (sperm cells) to the egg cell in the embryo sac during sexual reproduction. Pollen tube biology is complex, presenting parallels with axon guidance and moving cell systems in animals. Pollen tube cells elongate on an active extracellular matrix in the style, ultimately guided by stylar and embryo sac s...

In flowering plants, pollen grains germinate on the pistil and send pollen tubes down the transmitting tract toward ovules. Previous genetic studies suggested that the ovule is responsible for long-range pollen tube guidance during the last phase of a pollen tube's journey to the female gametes. It was not possible, however, to unambiguously identify the signaling cells within an ovule: the hap...

By the use of an immunofluorescence technique, the main source of the antigens released by the pollen grains of Phalaris tuberosa L. (Gramineae) on leaching has been shown to be the intine. The main concentration is in the thickened zone underlying the germination pore. The intine is also the site of various hydrolytic enzymes. The fate of the intine-held antigens has been followed in compatibl...

Plants being sessile by nature have developed sophisticated mechanisms to assist in their selection of mating partners. During a compatible pollination event, pollen grains that have landed on the stigmatic surface at the top of the pistil will adhere to the stigmatic cells, hydrate, germinate and form pollen tubes. The actively growing pollen tubes are often capable of penetrating the stigmati...

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...

A method is described by which the changes in shape that accompany hydration of Brassica pollen grains may be rapidly measured. Using this technique it has proved possible to chart the small amount of hydration that takes place on anthesis, in addition to the response of pollen to a range of relative humidities in vitro and in vivo. Such measurements, together with pollen transfer experiments, ...