POLLEN APERTURE AND SYMMETRY (PLANT SYSTEMATICS 2nd Ed)

PALYNOLOGY

1. POLLEN APERTURE AND SYMMETRY Prepared by: AIRA B. BELLEN BSEd 3-P

2. POLLEN APERTURE A specially delimited region of the pollen grain wall

3. FUNCTION Primarily to serve as the site of formation of a pollen tube exiting from the pollen grain body To allow volume changes of the pollen grain with changes in water content

4. HARMOMEGATHY Allows the pollen grain apertures to contract with water loss, effectively sealing the apertures via the surrounding desiccation resistant exine wall

5. POLLEN APERTURE TYPE Refers to the shape, number, position and arrangement of the aperture of a pollen grain INAPERTURATE – pollen grains that lack any recognizable aperture

6. GENERAL TYPES OF APERTURE COLPUS an elongate aperture with a length/width ratio of greater than 2:1 can be elliptic, oblong, or fusiform in outline shape

7. GENERAL TYPES OF APERTURE 2. PORUS a circular to slightly elliptic aperture with a length/width ratio of less than 2:1

8. Triporate Diporate Pentoporate

9. GENERAL TYPES OF APERTURE 3. PANTOPORATE if pori occur globally on the pollen grain surface

10. GENERAL TYPES OF APERTURE 4. COLPORATE shaped like a colpus but has a circular region in the center

11. GENERAL TYPES OF APERTURE 5. ZONOAPERTURATE /STEPHANOAPERTURATE pollen grains with apertures occurring in the equatorial region

12. GENERAL TYPES OF APERTURE 6. SULCUS an elongate aperture similar in shape of a colpus but either centered at a pole or more rarely, parallel to the equator

13. 7. ULCUS a circular to slightly elliptic aperture similar in shape to a porus but occurring at the pole GENERAL TYPES OF APERTURE

14. NUMBER OF APERTURES Designated by appending the prefix mono-, di-, tri-, tetra-, penta -, hexa -, or poly- (more than six) to the terms colpate and porate

15. RARE & SPECIALIZED APERTURE TYPES Syncolpate A pollen grain in which the colpi are joined Trichotomosulcate A three-branched aperture type Spiraperturate One or more apertures that are spirally shaped.

16. POLLEN SYMMETRY Generally either radially symmetric or bilaterally symmetric Often incorporated or assumed as a part of a shape term

17. THANK YOU!