Lesson 5 of 12 / Reproduction
Pollination: moving pollen to a stigma
Does moving pollen between two flowers always mean cross-pollination?
In this lesson: Define pollination and distinguish self-pollination from cross-pollination.
About 4 min
The key ideaPollination transfers pollen from anther to stigma. Self or cross depends on the plants involved, not simply the number of flowers.
The arrow traces pollen transfer. It does not represent gamete nuclear fusion.
Explanation
Pollination is the transfer of pollen grains from an anther to a stigma. Insects or wind can carry the pollen. The transfer itself does not yet fuse a male and female gamete nucleus.
Self-pollination includes transfer within one flower and transfer between two flowers on the same plant. Both cases involve the same parent plant as pollen source and recipient.
Cross-pollination transfers pollen between flowers on different plants of the same species. It brings genetic information from a different parent and can increase the combinations available in offspring.
When interpreting a diagram, identify the boundary of each plant. Two flowers drawn far apart can still be attached to one plant, while neighbouring flowers can belong to different plants.
Step by step
- 1
Identify source and destination
Pollen must move from anther to stigma.
- 2
Trace the stems
Decide whether both flowers belong to the same individual plant.
- 3
Name the process
Use self-pollination for the same plant and cross-pollination for different plants of the same species.
Worked example
Two flowers, one plant
An insect transfers pollen from one flower to another on the same plant. Classify the event.
One way to explain it
It is self-pollination because both flowers belong to the same plant, even though two flowers are involved.
Why this answer works
- The parent plant is the relevant boundary.
- An insect can cause either self- or cross-pollination.
Is this true? "Any pollination by an insect is cross-pollination."
The insect may move within one flower or between flowers on one plant. Check the source and recipient plants.