These types of tetrads are known as obligate or permanent tetrads. Pollen grains are arranged in two different planes. Three grains are in one plane and one lies centrally over the other three.Complete answer:
Tetrad is a gathering of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic microsporogenesis. The tetrads are of fundamentally five types namely tetrahedral (commonly), isobilateral, T shaped, decussate, and linear. In dicots, the widely recognized type of pollen tetrad is tetrahedral. The pollen grains are created within the anther of the flower. Pollen mother cells originate from the sporogenous tissue of the anther which later divides meiotically to form four pollen grains called a tetrad.
Four pollen grains are joined to form a tetrad. Tetrads are the unseparated result of meiosis. Tetrads may be categorized into diverse types based on their arrangement.
In some cases, the pollen grains are delivered from the anther in the tetrad state. Other names of these types of tetrads are obligate or permanent tetrads, viz., Drimys (Winteraceae), Drosera (Droseraceae), Rhododendron Ericaceae).
Hence, Option (C) is the correct answer. Additional Information:
Pollen morphology can be helpful in the determination of phylogeny and mating systems of plants. Pollen ovule ratios can give a sign of the mating system of plant species, and there are numerous theories as to decrease in response to pollination techniques.Note:
Moreover, morphological features of pollen grains have been categorized into many other diverse groups: 1. Pollen Units 2. Polarity 3. Symmetry 4. Shape 5. Size 6. Apertures 7. Sub-Divisions of the Pollen Surface 8. Sporoderm Stratification 9. Exine Ornamentation 10. ‘LO’ Analysis.