Why sunflower follows the sun?

The ability of plants to take a certain position under the influence of sunlight is called Heliotropism. At the beginning of the XIX century, this term introduced the Swiss and French nerd Okoustin Decandol-senior to describe the growth of the top of the stem towards the Sun. Plants can reach the light and unfold the leaves for greater ray grip. Heliotropism is characterized not only for sunflower, but also, for example, for a series, lotus, eucalyptus.

Plant growth hormone – Auxin – accumulates on the side of the sunflower, which is in the shade, and already at dawn it contains a large concentration of phytohormon. It turns out that during the day one part of the stem grows faster than the other, and the plant turns to the side of slower than growing cells, that is, to the light.

How does it find out when and where the sun goes from? In 2016, scholars of the University of California in Davis and the University of Virginia found out that the sunflowers were guided by internal biorhythms. This has proven experiment. Part of the sunflowers scholars landed in a laboratory in which the light was constantly included. And the other part is in the field, attaching some plants in such a way that they cannot unfold. It turned out that with artificial change in the duration of the light day of the plant lost the ability to navigate the sun. Consequently, sunflowers grown in the laboratory and in the field, but in fixed state, "lost" in time. As a result, their inflorescences grew slower, and the leaves were less. Moreover, they gave 10% less harvest than those sunflowers that grew in vivo.

In addition to the accumulation of greater biomass, the ability of sunflowers to turn after the sun has another advantage: allows you to attract more insect pollinators. The reason is simple: in the morning the inflorescences are turned east, which helps them quickly warm. And the bees prefer warm flowers and therefore flowed to sunflower much more often than to plants facing in the morning to the West.