pollen grain


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to pollen grain: pollen tube

pollen grain

a small structure of higher plants that contains haploid male gamete NUCLEI and is surrounded by a double wall, the EXINE and INTINE. As the pollen grain ripens in the pollen sac of the ANTHER, the nucleus divides by MITOSIS into two nuclei which have different functions, the ‘generative’ nucleus and the ‘tube’ nucleus (see POLLEN TUBE). Pollen grains are transported from the male stamen to the female stigma in a process called POLLINATION.
References in periodicals archive ?
In other species such as tobacco and cabbage, selective destruction of tapetal cells can disrupt the formation of pollen grain and lead to sterility (Cho et al.
Description: Pollen grain, monocolpate, overall amb elongate oval to fusiform, colpus distinct, running entire length of grain with a tendency to become narrow in middle with slightly expanded extremities.
Predominant pollen grains (PP, comprising more than 45% of the nectariferous pollen grains counted) belonged to Eucalyptus in two samples of Apis (Amparo-A and Lins-A) and one of Citrus (Itaberaba-A).
Because the growth medium was optimized for the pistil experiment, only a few pollen tubes emerge from pollen grains without contacting a pistil (Figure 3D, asterisk).
But other combinations seemed to pit pollen grain against pollen grain.
Cyclantherinae is characterized by pollen grains 4-8 colporate and punctitegilate (Marticorena, 1963; Jeffrey, 1990; Shridhar & Singh, 1990; Stafford & Sutton, 1994; Khunwasi, 1998), and Sicyinae by pollen grains 715 colpate and echinate (Marticorena, 1963; Shridhar & Singh, 1990; Khunwasi 1998).
Species can be identified from pollen grains, fragments of seeds or roots, wood, faecal samples, stomach contents or environmental samples collected from the air, soil or water.
This process removes residues and other substances from the surface of the pollen grain, revealing the exine structure.
The anther was gently squashed on a slide, covered with a 22 x 50 mm cover slip and the pollen grains were counted under 10x objective of a compound microscope.