It’s All About the Birds and the Bees

Before we delve into the ways plants are able to reproduce, it is important to understand some basic plant anatomy and the idea that plants may come equipped with male, female or both reproductive organs.

The basic anatomy is this: 

Female plants have several rows of cells called ovules within the ovary of the flower’s pistil (this is the female reproductive organ). As these cells mature, they become ready to develop seeds. Male plants undergo a similar process by developing pollen grains that contain sperm nuclei, encased in a protective outer coating. Pollination is the process that brings the DNA of the male flower into contact with the DNA of the female flower, a vital step in seed production that occurs once flowers begin to bloom.

Okay, so now that your plants are blooming, you know they are ready to reproduce. Unfortunately for them, they can’t just uproot themselves to attend a singles night, which means they have a bit of a problem (nothing a bit of creative trickery won’t fix).

There are a number of ways plants have evolved to combat this problem, the first of which is self-pollination. Self -pollination acts as a closed system where either a single flower will fertilise itself, or another flower on the same plant will be given pollination duties. The most important thing to remember here is that self-pollination is derived from a single genetic source, which means less genetic variety. Plants that self-pollinate are usually less genetically robust than plants that have been cross-pollinated and are therefore less likely to be able to withstand environmental changes like temperature lows, highs and even drought.

The second method plants will use to reproduce is called cross-pollination (this is where the creative trickery we mentioned earlier comes into play). In the interest of mutual survival, nature has developed a couple of assists to help plants with cross-pollination in the form of wind and wings.

The wind part is pretty simple, when a plant has ovules that are exposed, the wind can pick up pollen which will be naturally dispersed among surrounding plants.

Although the wind does play a role in nature’s pollination effort, most plants prefer a winged assistant to do the job (birds, bees, bats and other insects are the most common helpers). The process here is also simple but is further complicated when plants evolve to display traits that will make them more attractive to their primary pollinator. The process begins with our fliers looking for their dinner (the pollen or nectar produced by your plant). Factors including fragrance, shape and colour are all considered as these are usually indicators of readily available pollen and nectar.

As evolution occurs, plants are more likely to develop the traits that their pollinators are attracted to. For example, white flowers are preferred by nocturnal insects. Where these species are abundant, you are more likely to see high numbers of white, or yellow flowers. The pollinator lands on its chosen flower and leaves with a freight of sticky pollen (beekeepers affectionately refer to this as ‘pollen pants’), which is left behind as the flier visits subsequent flowers.

Data has suggested that around 75% of fruits, nuts and vegetables produced are pollinated by bees, which makes the information in this newsletter really important in understanding not only how your backyard ecosystem works, but also why an effort to conserve the bees is so essential to modern agriculture.