Morphological characteristics of pollen grains have been categorised into different 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. Characteristic # 1. Pollen Units: The pollen grains are produced within the anther of the flower. Pollen mother cells originate from [...]
In this article we will discuss about:- 1. Callose Wall and Meiocytic Syncytium 2. Ultra-Structural Changes in Microsporocytes 3. Cytokinesis. The sporogenous cells generally function directly as microspore mother cell, also called microsporocyte or pollen mother cell. They undergo meiotic division to give rise to microspore tetrads. This division is of tremendous importance in the life cycle of the Pteridophytes [...]
In this article we will discuss about:- 1. Meaning of Self-Incompatibility 2. Molecular Basis 3. Determinants 4. Significance. Meaning of Self-Incompatibility: Self-incompatibility or intraspecific incompatibility is a well-designed genetic mechanism by which certain plants recognize and reject their own pollen thus forcing outbreeding. It is defined as "inability of the plant producing functional gametes to set seed upon self-pollination",. Lundqvist [...]