A sapling grown from a cherry pip sent into space as part of an education experiment has stunned scientists in Japan by blooming far earlier than its earth-bound relatives.
According to botanists, cherry trees generally take about a decade from the time they sprout before buds first appear. The cherry pip that was sent to the International Space Station five years ago has achieved that just four years after sprouting.
"It is difficult for us to judge why this has happened, but one reason the tree has grown so fast may be related to space rays," said Kaori Tomita-Yokotani, a researcher at the University of Tsukuba.
"We have to study this further and repeat our experiments on earth to try to understand the mechanisms that are at work."
The Space Cherry project was dreamed up by Japan Manned Space Systems as a project with a uniquely Japanese angle for the astronaut Koichi Wakata.
A total of 265 cherry stones from the famous Chujohimeseigan-zakura cherry tree, in the grounds of Ganjoji Temple in Higashiomi, were selected for the experiment. The tree is believed to be 1,250 years old and is a variant of a wild cherry that has previously defied efforts to produce young trees from its fruit.
After Wakata arrived aboard the ISS in 2008, he began a series of experiments, including the Space Cherry, and returned to earth in July 2009 with the fruits of those labours.
Of all the cherry stones that were taken into orbit, a handful were selected for careful attention after returning to earth.
Botanist Takao Yoshimura used a method of covering the stone with soil and then moss. Within four years, the sapling had reached a height of four metres and was in bloom last week.
Many of the cherry stones were planted in Japan and have similarly come into bloom much earlier than anticipated.
In another unexpected development, the flowers of the Space Cherry tree have only five petals. Those on the parent tree each have around 30, and the experts believe the sapling may have reverted back to the characteristics of the original species.
The discovery had interesting implications for humankind, Tomita-Yokotani said, including the possibility of large-scale agricultural plants in outer space being used to grow crops at a faster rate than on earth.
"These pips were in an environment on the ISS that was suitable for humans, but it would be necessary to develop enclosed ecosystems on planets that do not have an atmosphere."
Space scientist Dr Masamichi Yamashita has already proposed the creation of extensive agricultural facilities on Mars.