Sex life of plants reveals disagreements between the sexes

The pollen grains of male plants must live in stiff competition. A pollen developed successfully in the pistil is the winning reward of competition. This has been demonstrated by a study by Lund University - Sweden.

Associate Professor Åsa Lankinen and his doctoral candidate Josefin Madjidian - Lund Department of Plant Ecology at Lund University - are studying sexual disagreement and chalk competition in plants. Their research shows that disagreements between the sexes really exist .

Åsa Lankinen said: 'We have observed that some pollen grains can affect the pistil in ways that give advantages. But at the same time this strategy is harmful to trees. ' When pollen grains from different plants fall to the pistil surface, competition arises to determine which pollen will have the opportunity to fertilize oocytes in the ovary. Ovule is located at the bottom of the pistil. Pollen grains need to have long pollen tubes that can rapidly penetrate the surface of the pistil and develop to the oocyte.

Collinsia heterophylla flowers at the Blue Sky ecological reserve in Poway, California.(Photo: Wikimedia Commons)

Lankinen and Madjidian studied a species of flowering plants in North America called Collinisa heterophylla. Normally, pollen grains of this plant must wait for the pistil a few days before the pistil surface can penetrate.However, research shows that some pollen grains can affect the pistil surface in a way that allows their pollen tubes to successfully penetrate the pistil before other pollen tubes can do so. This phenomenon means that they may be the first pollen grains to reach the ovule in the ovary.

The change of pollen grains may bring personal benefits but at the same time there is a negative effect on the number of seeds formed. The pistil may seek to prevent the phenomenon, leading to the formation of an armed race between the sexes. The study also offers direct evidence of such a race, but researchers still can't say exactly how it works.

Åsa Lankinen said: 'It is very difficult to detect gender conflicts like this to point out the relevant characteristics. In general, female trees can affect pollen competition by developing longer pistils or developing larger receptors, for example. But here we predict that the explanation is related to how the pistil can chemically affect pollen '.

References:
Josefin A. Madjidian, Åsa Lankinen.Sexual Conflict and Sexually Antagonistic Coevolution in an Annual Plant security.PLoS ONE, 2009;4 (5): e5477 DOI: 10.1371 / journal.pone.0005477