With the help of fluorescent glowing proteins, scientists are now starting to understand when and how flowers shed their petals.
O. Rahul Patharkar, a postdoctoral fellow in the University of Missouri's Division of Biological Sciences who led the research, said the study sheds light on abscission, a process through which plants shed their leaves, petals, fruits and seeds.
The study involved the abscission process in Arabidopsis thaliana, which provides a base for understanding the essential process that is also found across other species of plant.
The researchers explained that early abscission steps include alterations to a distinct cell layer, which is called the abscission zone. This cell layer is usually found at the base of a flower. When a flower ages, the cells in this particular layer start to isolate from each other and create a clean gap in between the petals and the base.
When the gap increases, the petals fall. For a long time, scientists have wondered how plants regulate the process of cell separation.
"We know that when a plant is a little ways away from abscissing its petals, the activation of genes is already beginning. A lot of this gene activity, which we call transcription, is exponentially increased in a relatively short time, which ultimately leads to abscission," said Patharkar.
The researchers revealed that a gene called HAESA gets an enhancement in the process. Previous studies suggested that HAESA activity increases by 27 times, from the budding of a flower to the shedding of its petals. The latest study also explained the reasons for the gene expression.
Plants that overexpress AGL15, a plant protein, do not trigger HAESA, so the flowers do not shed petals. The findings showed that AGL15 averts the expression of HAESA by hindering its transcription.
Another group of proteins called MAP kinases turns off AGL15, which means that HAESA signals to the MAP kinases to do their work.
The study has brought together different proteins and genes in a fresh model, which explains floral abscission. The study is important as it may benefit the cut flower and fruit industry, whose products need to stay fresh and intact for long.