For some of you just hearing the word “botany” brings forth images of dreary classroom sessions and nerdy be-spectacled professors with wild unkempt hair. My experience of botany has been quite the opposite (well, except for maybe the unkempt hair). Botany is all about the sex lives of plants. Flowers, the sex organs of plants, are quintessentially beautiful and incredibly diverse. Pollination is an intricate a dance of plant insect wind and chance. If you have never taken a field study course, it is highly recommended. Heading down a mountain path in search of some obscure beauty, you never know what wonders nature will show you along the way. Botany classes for non-academics are available at the Jepson Herbarium, Sierra Nevada Field Campus and Tilden Botanic Garden (besides their public classes they also offer a 20 week docent training)
In the garden some knowledge of plant taxonomy is necessary of you want to take your sustainability and skills to the next level. Plants in the same family act similarly in how they reproduce and plants of the same species may or may not cross to produce something that resembles the parent. This is important if you want in on the tradition of saving and growing out your own seed. Seed is living gold; the genetic material of the flavours we love. Saving heirloom seed properly is the next step in true sustainability and independance from giants like Monsanto.
How Pollination Happens
The female part of the flower is called the pistil which includes the stigma, style and ovary. The stigma has a sticky surface which will chemically “recognizes” only pollen of the same species. The ovary, is what will become the fruit and within it the seeds. The male part of the flower is the stamen which includes the filament and anther. The anthers produce the pollen. Some plants have male and female parts in the same flower and are self-pollinating within the same flower. Tomatoes are an example of this. Some have male and female parts in the same flower, but have evolved mechanisms to prevent self-pollination and ensure genetic diversity. Some plants have separate male and female flowers on the same plant, such as zucchini and other squash. Finally, some plants have male and female flowers on separate plants, thus requiring two plants to reproduce. Avocado trees are an example of this.
So finally getting to the amazing part, here. The pollen grain is made up of 2 cells. When a pollen grain of the right type lands on the sticky stigma, the hard outer coat of the pollen grain starts to dissolve. The first cell, called the “tube cell” grows like a tube down the style to the ovary where the second cell fertilizes the ovule to make a seed. The tube cell can grow as much as 12 inches to reach it’s goal! In corn, for example, each silk is one style leading to one ovule which will become one kernel of corn. When the pollen from the tassels lands on the silks, the pollen tube grows all the way down the silk to fertilize the one ovule. Wow. This story will continue next month with a bit about plant families and beginning seed saving!