Fig. 255 Pollen tube . Section of grain, showing tube.

pollen tube

a slender structure produced from a POLLEN GRAIN after POLLINATION. The tube protrudes from a pore in the EXINE and grows down through the stigma, style and ovary of the CARPEL, entering the ovule usually by the micropyle. See Fig. 255 . Within the tube, the haploid generative nucleus divides by MITOSIS to give two MALE GAMETE NUCLEI which have an important function in the double FERTILIZATION process of higher plants (see EMBRYO SAC). The growth of the tube appears to be controlled by the tube nucleus and there is some evidence that the tube shows negative AEROTROPISM. The stimulus for the original germination of the pollen grain comes from a sugary fluid secreted by the stigma. Sometimes, however, germination is prevented by SELF-INCOMPATIBILITY factors in the stigma cells and pollen grain, which prevent self-pollination in some plants.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

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References in periodicals archive

The entire process, from the deposition of pollen on the micropyle, followed by pollen tube growth and fertilization of the egg, takes considerably longer in cycads and other gymnosperms than in angiosperms.

Comparative Biology of Cycad Pollen, Seed and Tissue--A Plant Conservation Perspective

PEAMT and GPAT6 also affected pollen tube growth [46, 92].

Identification of Wheat Inflorescence Development-Related Genes Using a Comparative Transcriptomics Approach

Staining and observing pollen tubes in the style by means of fluorescence.

Reproductive biology of endemic Solanum melissarum Bohs (Solanaceae) and updating of its current geographic distribution as the basis for its conservation in the Brazilian Cerrado/Biologia reprodutiva da endemica Solanum melissarum Bohs (Solanaceae) e atualizacao da distribuicao geografica atual, como base para a sua conservacao no Cerrado Brasileiro

Pollen grains were considered germinated when the length of pollen tubes exceeded grain diameter.

In vitro pollen viability of maize cultivars at different times of collection/ Viabilidade in vitro de polen de cultivares de milho em diferentes tempos de coleta

Self-pollination at bud stage aims to enable self-fertilization before the glycoproteins reach levels that prevent the development of the pollen tube (ROBERTS et al., 1979).

Method for overcoming the passion fruit self-incompatibility/Metodo para superacao da autoincompatibilidade do maracujazeiro

The essential role of calcium ion in pollen germination and pollen tube growth.

IMPROVEMENT OF THE POLLEN QUALITY AND GERMINATION LEVELS IN GRAPES (VITIS VINIFERA L.) BY LEAF PULVERIZATIONS WITH NANOSIZE CALCITE AND SEAWEED EXTRACT (ASCOPHYLLIUM NODOSUM)

There are six phenotypic classes of pollen tube, five of them mutagen namely, balloon, wavy, branch, swollen, thin and only one is normal namely wildtype [43].

Improving pollen tube morphology of Solanum melongena L. using date palm pollen extract

Hoshikawa et al., "Characterization of fruiting and pollen tube growth of apple autotetraploid cultivars showing self-compatibility," Journal of the Japanese Society for Horticultural Science, vol.

Apple pollination biology for stable and novel fruit production: search system for apple cultivar combination showing incompatibility, semicompatibility, and full-compatibility based on the S-Rnase allele database

The pollen attributes namely pollen viability; pollen size, pollen germination, and pollen tube length were measured with the help of microscope and micrometer.

FLORAL ATTRIBUTES OF PASSION FRUITS (Passiflora edulis Sims.) AT VARIED FLASHES

Though a number of existing teaching activities deal with in vitro pollen tube growth on medium, didactically prepared visualization of pollen tube growth in vivo is more ambitious and usually needs fixed material and advanced equipment (e.g., fluorescence microscopy).

Plant reproduction & the pollen tube journey--how the females lure the males

Pollen viability and germination was assessed in vitro and in vivo as well as pollen tube growth rate and velocity within the .floral gynaecium, in order to detect possible malfunctions in the pollination process that could explain disorders such as lack of fruit set and excessive nubbin formation.

Pollen viability and germination in mango (Mangifera indica L.) cv. ataulfo/ Viabilidad y germinacion del polen en mango (Mangifera indica L.) cv. ataulfo/Viabilidade e germinacao do polen na mangueira (Mangifera indica L.) cv. ataulfo