Plant & zo
The science of plants and more
Getting it just right
Plants can’t change place when their environment changes. Whether it is warm or cold, wet or dry, all a plant can do is adapt. One of the things it adapts is the size of its flowers. German researchers found out that under warm conditions the flowers are smaller than under cold conditions.
Flowers, and their size, are important for the reproduction of the plant. Larger flowers are attracting more pollinators. However, flowers also house the pollen and ovules, which are not allowed to get overheated, something easier prevented in small flowers. It is thus a balancing act to get the flower size precisely right.
To analyse the effect of the temperature, the researchers grew multiple tale cress (Arabidopsis thaliana) and its close relative sand rock-cress (Arabidopsis arenosa) at 17 and 23 °C. The researchers noticed that the flowers of both tale cress as its close relative sand rock-cress were smaller at 23 °C than at 17 °C. Although the size difference was smaller for the pollinator dependent sand rock-cress than for the self-pollinating tale cress.
The MAF gene on/off-switches are responsible for getting the flower size just right
In response to a higher temperature a plant of course adjusts more than just its flower size. For example, it also adjusts the size of its leaves and the time of flowering. The researchers analysed these traits together with flower size. And although all three traits show temperature response, it appears that these traits are regulated independently.
The temperature dependent flower size, the researchers found out, is regulated by a group gene on/off switches, MAF2 to MAF5. Flower size is less dependent on temperature in plants without any MAF2, MAF3 or MAF4. Those plants had already smaller flower sizes at 17 °C. No larger flowers without MAF2, 3, or 4. But, so observed the researchers, there is no difference in the amount of MAF2, 3, 4, or 5 at 17 or 23 °C. The reaction to a higher temperature is independent of a gene on/off-switch for MAF2, 3, 4, and 5.
To much heat does no good to a flower. The MAF gene on/off-switches keep an eye on the temperature and react when the heat gets to much. They are responsible for getting the flower size just right. But how exactly they do this is still unknown.
Wiszniewski, Andrew; Uberegui, Estefanía; Messer, Michaela; Sultanova, Gulmairam; Borghi, Monica; Duarte, Gustavo Turqueto; Vicente, Rubén; Sageman-Furnas, Katelyn; Fernie, Alisdair R; Nikoloski, Zoran; Laitinen, Roosa A E (2022) Temperature-mediated flower size plasticity in Arabidopsis. iScience 25, 105411 https://doi.org/10.1016/j.isci.2022.105411