Russian scientists have found patterns, which are formed the bodies yellow capsule Nuphar lutea. They showed that all the elements of the flower are arranged in circles, and not sitting consistently in a spiral, as in some other basal angiosperms. The work of scientists published in the journal Frontiers in Cell and Developmental Biology.
The flower is, perhaps, the most important evolutionary acquisition of angiosperms. It allows you to attract pollinators, to protect the seeds inside of the fruit and spread more effectively some of the ancient gymnosperms. These advantages have allowed Tsvetkov plants to spread across the planet and become the largest group of terrestrial plants.
However, until now it is unclear how any of the colors and how they looked at first. About to restore the ancient appearance of the flowers you can use plants that remained most similar to the first angiosperms. Looking for such plants among the basal groups — those in which the ancestors were separated from the common stem of flowering. They have the structure of the flower is with high probability similar to the ancestral species.
Among modern plants closest to the base of the trunk to the ancient lilies are angiosperms. In Eurasia, widespread Nuphar lutea (Nuphar lutea). It can also be found in North America. Due to this, it could be a convenient model object. However, until now the development of her flower, using the exact methods were not described.
To do this it was decided biologists from Moscow state University. M. V. Lomonosova and the higher school of Economics. They took a dozen rhizomes of Nuphar lutea leaves and flowers. Some of them cut into pieces and then created drugs for light and scanning electron microscopy. Only the researchers carefully examined the tops of the shoots, which laid new leaves and flowers. As objects, the researchers used the young flowers at different stages of development. To determine the structure the authors have carried out measurements of the angles between the same elements of the flower.
Very often plants have leaves, flowers and lateral buds and shoots formed from them arranged in a spiral. Previously, researchers have assumed that the same form is characteristic of the flowers, whose structure is close to the original type for angiosperms, including for egg capsules. But it turned out that the capsule within a single flower the angles between the sepals not similar to helical (85°and 55°, and not 137,5°). The researchers showed that the sepals and petals forming circles and are located on one level, although within range, they do not have laid all at the same time.
The capsule five sepals. If they were all in the same whorl, the angle between the “neighbors” would be 72°. But in reality, they are located at such angles that actually were in two circles: the three elements in the outer and two in the inner. The number of petals ranged from 14 to 15, but they formed the only circle, not a spiral. And even most of the stamens have sought to line up in a circle, forming several rings.
On the basis of this plant, scientists are trying to conclude how it looked the first flowers. But for testing emerging hypotheses, they need good models. Lilies have long claimed the role of this model, but it was necessary to find out some details of their structure and development of flowers. The creators of the work described different stages of flower typical of the species lilies. They used an objective parameter — the angles between the bodies. For the Eurasian species of lilies is done for the first time.
