In this article we will discuss about the chemical composition and functions of plasma membrane. Chemical Composition of Plasma Membrane: The membrane is mainly composed of lipids, proteins and carbohydrates. Water makes about 29% of total weight. Robertson (1959) proposed that plasma membrane is three-layered structure where proteins form the outer and inner layers of membrane that encloses lipids to [...]
Sporoderm defines the shape of a pollen grain and spore. Erdtman (1952) distinguishes nine common types of shape (Fig. 4.33). The shape classes are based on the ratio between the length of polar axis (P) and equatorial diameter (E). P and E are measured from the equatorial view of a pollen grain and spore. Measurements are taken from the optical [...]
The following points highlight the nineteen main sculpture types that ornament both pollen and spore. The sculpture types are: 1. Chagrenate 2. Psilate 3. Spinula 4. Spina 5. Pilum 6. Verruca 7. Gemma 8. Clava 9. Baculum 10. Scabrate 11. Rugulate 12. Striate 13. Cicatricose 14. Reticulate 15. Corrugate 16. Foveolate 17. Fossidate 18. Canaliculate 19. Echinate. Sculpture Type # [...]