How Do Flowers Know When Its 'Time' to Start Blooming?

Have you ever wondered how flowers always happen to follow a designated routine and appear at a certain time of the year? What gives them this ability to form in a correct shape and in a certain time frame. 

Answering these questions is the study published in the Proceedings of the National Academy of Sciences USA which was conducted by four scientists from Nanjing University, China, and Biological Sciences, Nara Institute of Science and Technology, Japan.

The group of scientists have discovered that a small protein plays multiple roles to ensure that floral reproductive organs are formed properly within a short space of time. Floral meristems differentiate to produce the sepals, petals, stamens, and carpels, the various parts of a flower. 

Researchers have found in their study that the development of these floral organs is dependent on meristem development which needs to be completed within a certain time frame. The stem cells provide the cell source for floral organ formation in the nascent stages of flower development. 

Meanwhile, in floral meristems, stem cell activities are maintained through a feedback loop between WUSCHEL (WUS), a gene that identifies floral stem cells, and CLAVATA3 (CLV3), a stem cell marker gene that is activated and sustained by WUS, mentioned the study.

Lead author of the study, Erlei Shang said in a statement, that a small protein called KNUCKLES (KNU) represses WUS directly, which leads to the completion of floral stem cell activity at the right time. However, they further mentioned that what is not fully understood is how the robust floral stem cell activity finishes within a limited time period to ensure carpel development.

Senior author Toshiro Ito said that their research revealed that in Arabidopsis thaliana, also known as the thale cress, mouse-ear cress or arabidopsis, which is a small flowering plant native to Eurasia and Africa, KNU can completely deactivate the robust floral meristems at a particular floral stage. It is because of the multiple functions that KNU carries out via its position-specific roles.

The corresponding author Bo Sun said in a statement that the results of their study have shown a regulatory pathway where KNU plays a crucial role in assisting the completion of floral meristem development within a short time period and ensures that flower reproductive organs are properly formed.

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Buxone Spotlight September 26, 2021