That's what brought Williams to a harness in the rainforest of Australia. To confirm what he found in the data analysis, he pollinated -- by hand -- an ancient vine known as Austrobaileya that grows high in the canopy. He chose that plant, along with another plant found only on the Pacific island of New Caledonia and a water lily that grows high in the Colorado mountains, to test because they developed as species early in flowering plants' evolution.
He found that, when compared to more recently evolved species of angiosperms, the older plants grew shorter pollen tubes and took longer to do so than more diverse modern species. According to Williams, this indicates that these pollen tubes likely played a previously unknown role in spurring the evolution of the roughly 250,000 species of flowering plants we see today.
"As these plants gained the ability to grow pollen tubes faster and over longer distances," said Williams, "It gave them the ability to develop the much larger and more complex flowers as well as deeper ovaries with more seeds -- that is to say, larger fruits -- that we see around us today."
|Contact: Jay Mayfield|
University of Tennessee at Knoxville