This week we’re featuring five winners of the 2012 Academic Minute Senior Superlatives.
Chris Martine from SUNY Plattsburgh took home the Best Smile honor for letting us in on the secret world of plant sex.
Chris Martine is now Associate Professor and David Burpee Chair in Plant Genetics & Research at Bucknell University. As a biodiversity scientist, Martine has a particular focus on the ecology and evolution of plant and the process of reproduction. He has published numerous articles on the subject, and in 2011 received the SUNY Chancellor's Award for Excellence in Teaching. He holds a Ph.D. in botany from the University of Connecticut.
Dr. Chris Martine – How Plants Reproduce
Look around the room at most social gatherings. and you are likely to notice something about sex. I am speaking, of course, about the fact that human beings come in two genders: male and female. In fact, this is how things are for most of the species in the animal kingdom.
In the plant kingdom, however, things are quite different. More often than not, plants are cosexual: each individual plant has both male and female organs, with each of these producing either male sex cells (sperm) or female sex cells (eggs) - all on a single plant.
The rare condition in plants is when they appear as we do, with some individuals in a population having just male, or staminate, organs and others bearing only female, or pistillate, organs. This system is known as "dioecy," which literally means "two houses" - and it results in the fact that in a dioecious species (where males and females live apart) there is no way for a single individual plant to reproduce by itself. The male plant is dependent on the secure delivery of its sperm cells (in the pollen grain) to a female plant of the same species.
Something like 5 to 10 percent of the flowering plant species on Earth reproduce in this manner, with the rest enjoying the reproductive assurance of being able to make more of themselves even when another mate is nowhere to be found. So if the ability to self-produce works for so many plants, why would dioecy and the obligation to "find" another mate have evolved and be so widespread, occurring in dozens of unrelated plant lineages - from hollies to willows to Cannabis?
It turns out that one potential downfall to being able to fertilize yourself is ... well, that you can fertilize yourself. Dioecy might just be a way to avoid the pitfalls of becoming inbred. And in the plant world - where you can't get up and go and find a mate - this is one of the few ways to take reproductive matters into your own leaves.