Fourteen days passed since you planted Fast Plants, and yellow flowers are opening! Ready your bee sticks; it's time to pollinate!!
Pollination is the transfer of pollen from the pollen-bearing, male anthers to the pollen-receptive, female stigma of flowers, resulting in fertilization. Pollination can occur via self-pollination or cross-pollination.
Self-pollination is the transfer of pollen among flowers on one individual plant.
Self-pollination is only possible when plants are self-compatible.
Some plants are able to self-pollinate automatically, without needing the transfer of pollen by a pollinating agent (such as insects or wind).
Cross-pollination is the transfer of pollen between at least two individual plants.
Cross-pollination is necessary when plants are self-incompatible.
Cross-pollination requires that pollen be transferred by a pollinating agent such as an insect or wind, or through human-mediated pollination or plant breeding.
A plant that is self-incompatible can detect and reject pollen from itself. Therefore, even if pollen from one of it's own flowers is transferred to the stigma of the same flower or another flower on the same plant, fertilization does not occur. Self-incompatible plants require pollen from another plant for successful pollination and fertilization. This mechanism promotes genetic diversity in a population.
Why do we pollinate Fast Plants?
Fast plants are self-incompatible; thus, cross-pollination is necessary to produce seeds.
In a classroom or lab setting, humans act as the pollinating agent by transferring pollen from the pollen-bearing anthers to the pollen-receptive stigma.
After the act of pollination, pollen germinates on the flower’s stigma and grows through the style to reach and fertilize the egg cell within the ovule.
In nature, bees are the primary pollinating agent for Brassica relatives of Fast Plants. For your classroom, we recommend the “beestick” tool for pollinating Fast Plants. A beestick is a dead bee glued onto a toothpick and used to collect and transfer the pollen among flowers. (While a beestick is the most effective pollination tool, alternatives, to the beestick, such as a cotton swab, small paint brush, or commercially supplied pollination wand can also be used).
How do I know when it's time to pollinate?
Some time between Day 14-16, when three or more flowers are open on each plant, begin pollinating. We recommend holding a flower in one hand and gently rolling the beestick back and forth over the anthers and stigma tip of the pistil until yellow pollen can be observed on the hairs of the bee thorax. Repeat with all open flowers on each of your plants.
For successful cross-pollination, move to another person’s Fast Plants, and repeat the gentle rolling motion over the anthers and the stigma of each pistil, making sure to deposit pollen collected on the beestick to the stigma of each flower. Be gentle, so as not to break the stigma.
Before leaving the plants, check that each stigma received pollen (this is easy to do, now, with those Fast Plants that have purple stigmas!
Optimal seed production results if pollination is done daily or every-other-day for a total of 2-4 pollination sessions, after the first flowers open on the plants.
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