Researchers from the University of Bristol announced that they have
discovered the secrets to shoot evolution. Their findings indicate that
plants half a billion years ago had a budding mechanism for shoot
development when they first emerged on land.
The study points to genes responsible for how plants from 450 million years
ago were able to delay reproduction and grow shoots, leaves, and buds. This
evolution involves a switch that allowed plants to shift new cells downwards
from the shoot tips.
Several modern developmental and genetic techniques were used to investigate
the swollen reproductive structures of mosses located at the tips of their
small stems. Moss was selected as it embodies the starting point of plant
evolution. It was found that mosses are raised upwards by new cells formed
in the middle of the stem. Further investigation found that similar genes
are responsible for elongating the moss' stems.
These findings lead the researchers to conclude that there was a
pre-existing genetic network in emerging plants that was remodeled to allow
shoot systems to arise in plant evolution. This also suggests that radiation
of shooting forms may have been triggered by a change in timing and location
of gene activity. The new information can help scientists understand better
how genes control plant shape, which can lead to future research on
improving the characteristics and yield of crops.