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Each theca contains two microsporangia, also known as pollen sacs. The microsporangia produce the microspores, which for seed plants are known as pollen grains. If the pollen sacs are not adjacent, or if they open separately, then no thecae are formed. In Lauraceae, for example, the pollen sacs are spaced apart and open independently.
Bees in four tribes of the family Apidae, subfamily Apinae have corbiculae: the honey bees, bumblebees, stingless bees, and orchid bees. [14] [15] The corbicula is a polished cavity surrounded by a fringe of hairs, into which the bee collects the pollen; most other bees possess a structure called the scopa, which is similar in function, but is a dense mass of branched hairs into which pollen ...
Trinucleate – pollen containing three nuclei when shed. Valvular – anthers opening through valves or small flaps; e.g. Berberis. Versatile – anthers pivoting freely on the filament. Pollen – Stamen – Anther – the distal end of the stamen where pollen is produced, normally composed of two parts called anther-sacs and pollen-sacs .
The microspore can then go one of four ways: Become an embryogenic microspore, undergo callogenesis to organogenesis (haploid/double haploid plant), become a pollen-like structure or die. [ 6 ] Microspore embryogenesis is used in biotechnology to produce double haploid plants, which are immediately fixed as homozygous for each locus in only one ...
Schematic cross section of an anther. 1: Filament 2: Theca 3: Connective 4: Pollen sac (also known as sporangium) In botany, the connective is the portion of sterile tissue of the anther between and interconnecting the two thecae, [1] [2] which forms a body with them and holds them together.
Under each microsporophyll is one or several microsporangia (pollen sacs). The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which when fertilized by pollen become seeds. The female cone structure varies more markedly between the different conifer families and is often crucial for the identification of many species of ...
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
A floral diagram, with the pollen tube labeled PG Fertilization , also called Syngamy , is preceded by pollination, which is the movement of pollen from the stamen to the carpel. It encompasses both plasmogamy , the fusion of the protoplasts , and karyogamy , the fusion of the nuclei .