Pollen Morphology Training - Part 2: Apertures

Summary

This video on pollen morphology provides an in-depth look at pollen apertures, focusing on their types, measurement methods, and morphological characteristics. It covers various aperture types, such as pores and kopis, their roles in pollen identification, and how aperture positioning helps determine a grain’s orientation. The video also discusses the classification of grain polarity, the process of measuring apertures, and how to observe the shape, section, and other features like colby margins and operculum. Overall, it’s a comprehensive guide for understanding the role of pollen apertures in taxonomy and identification.

Takeaways

• 😀 An aperture is an area on the pollen wall that appears different from the rest of the surface and serves as the site of germination on the pollen grain.
• 😀 Pollen grains typically have one or more apertures, which provide useful morphological information for identification.
• 😀 Two common types of apertures are pores (circular or elliptical) and cope (elongated), and grains can exhibit both types, forming the morphology 'co 4 8'.
• 😀 The position of apertures helps determine a grain's orientation, whether polar or equatorial.
• 😀 In equatorial orientation, pores are usually situated around the equator, while cope runs from pole to pole.
• 😀 Polar grains can be classified as either isopolar (symmetrical) or heteropolar (asymmetrical). Some grains lack discernible poles.
• 😀 Aperture position further refines the description of a grain's morphology, helping to categorize it based on the location of the apertures.
• 😀 Proper measurement of pores involves determining the grain's orientation, then measuring the height (polar) and width (equatorial) of the pore.
• 😀 The measurement of cope involves determining its widest point, also based on the grain's orientation.
• 😀 Pore shapes can vary from circular to irregular, providing useful tools for pollen identification, with examples like concave, irregular, and sunken pores.
• 😀 Cope morphology includes characteristics like margin variations (margo), apex shape (acute or round), operculum presence, and constriction near the equator, which all aid in identification.

Q & A

What is a pollen aperture?

A pollen aperture is an area on the pollen wall that appears morphologically different from the rest of the surface. It functions as the site for germination and provides useful information for pollen identification.

What are the two common types of apertures in pollen grains?

The two common types of apertures are pores and kopi. Pores are generally circular or elliptical, while kopi are elongated apertures.

How do apertures help in determining the orientation of a pollen grain?

The location of apertures on a pollen grain helps determine whether the grain is in its polar or equatorial orientation. Pores are usually seen around the equator, and kopi run from pole to pole.

What is the significance of determining the polarity of a pollen grain?

Determining polarity helps classify the grain as either iso-polar (symmetrical poles) or hetero-polar (asymmetrical poles), which aids in understanding its morphological characteristics.

How do you measure a pore on a pollen grain?

To measure a pore, first determine the grain's orientation. For the polar measurement, measure the height of the pore, and for the equatorial measurement, measure its width across the equator.

What are some examples of different pore shapes?

Pore shapes can vary from circular or squared to elliptic, rectangular, irregular, or inconspicuous.

What does a 'poor section' of a pollen grain refer to?

A 'poor section' refers to the shape and structure of the pore when the grain is viewed in the polar orientation. Observing this section helps in identifying the specific type of pore present.

How is the length of a kopi measured?

The length of a kopi is measured visually from one pole to the other. The length may vary from less than one-third of the grain's height to the full length of the grain.

What is the 'Margo' in relation to a kopi?

The Margo is the area surrounding a kopi that may vary in thickness or ornamentation. It is the margin of the kopi.

What are the different types of kopi apices?

The apices of a kopi can be classified as either acute or round, depending on the shape observed in the polar orientation.