| 词汇 | pollen |
| 释义 | pollen noun[ U ] uk /ˈpɒl.ən/ us /ˈpɑː.lən/ a powder, produced by the male part of a flower, that causes the female part of the same type of flower to produce seeds. It is carried by insects or the wind.花粉 paulbein/iStock/Getty Images Plus/Getty Images /GettyImages Plant reproduction anther asexual reproduction asexuality asexually barrenness breeder chasmogamous endosperm palynology pistillate placentation pollinate pollination self-fertilize self-incompatible self-pollination sexlessly siltation stamen wind pollination You can also find related words, phrases, and synonyms in the topics: Flowers - general words pollinateverb[ T ]uk /ˈpɒl.ə.neɪt/ us /ˈpɑː.lə.neɪt/ Bees pollinate the plants by carrying the pollen from one flower to another.蜜蜂把一朵花上的花粉带到另一朵上来给植物授粉。 pollinationnoun[ U ]uk /ˌpɒl.əˈneɪ.ʃən/ us /ˌpɑː.ləˈneɪ.ʃən/ Many species of tree depend on the wind for pollination.许多树种依靠风来授粉。 pollen | American Dictionarypollen noun[ U ] us/ˈpɑl·ən/ biology a powder produced by the male part of a flower that causes the female part of other flowers of the same type to produce seeds Examples of pollenpollen This means that pollen transferred within a patch contributes to geitonogamous self-pollination. Secondly, inflorescences were visited by numerous nitidulids almost always loaded with pollen. The airstream directs the pollen up a tube having openings, at several different points along its length, through which the pollen is dispersed. Pollen records poorly reflect cyclical droughts seen in isotopic records, as natural vegetation has adapted to these fluctuations. Some core sections had decreased in length due to dewatering since the cores were originally collected and sampled for pollen and microscopic charcoal in 1989. The total number of pollen grains, the number and percentages of species-specific grains and recognizable heterospecific pollen types are shown. The following sequence of floral parameters was noted: anthesis, odour release, nectar secretion, pollen liberation, and receptivity of stigmas. The attraction of both predators to the leaves containing pollen may be the reason for the lower levels of predation on the plants containing pollen. Values are expressed as percentages of the pollen sum. Elements of the local mire vegetation, fern spores and other palynomorphs were not included in the pollen sum. With pieces of tape, pollen was sampled from forehead, throat and cheeks and studied in a scanning electron microscope. This method uses a mixture of anhydrous acetic acid and sulphuric acid, which is heated to prepare pollen for examination under a light microscope. We detected significant structuring of style morphs and neutral markers in populations, probably because of restricted pollen and seed dispersal. The discernible pollen types of heterospecific pollen were noted, but it was not always possible to count these types individually. The hind legs and lower abdomen rapidly became coated with a thick layer of pollen. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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