the power of pollen

Maria Teresa Gomez Sagasti, University of the Basque Country / Euskal Herriko Unibertsitatea

The beginning of spring, dry and hot, has caused a significant increase in pollen levelsone of the most common allergens on the European continent. Despite their tiny size – and being a nightmare for allergy sufferers – pollen grains fulfill an essential ecological function for the survival of humanity. It is time to value it as it deserves.

The spark that ignites plant life

more than 350 million years ago, a lineage of plants, the gymnosperms (with naked seeds, such as firs, cedars and pines), developed grains of pollen and seeds, marking a before and after in reproduction and adaptation to the terrestrial environment of the plant kingdom.

Two hundred million years later, in full terrestrial revolution of the Cretaceous, plants with flowers and seeds protected by fruits appeared: angiosperms. Thanks to the evolutionary ingenuity of pollen and flowers and their co-evolution with pollinators, angiosperms diversified rapidly, dressing the planet in a multitude of vibrant colors. They are the ones that today dominate terrestrial ecosystems and the main protagonists of farmland.

More than an allergen

Pollen, that often golden dust that wafts through the air in spring and summer, is actually a tiny but powerful reproductive structure. The mature pollen grain is the male gametophyte of plants. It contains three cells, two spermatic and one vegetative. protected by a double envelope that gives it resistance. It is produced in the male organs of angiosperms (stamens) and gymnosperms (male cone).

The pollen grain functions as an intermediary that transports male genetic material from the parent plant to the female organs of other plants. Or herself, in some cases. This is how fertilization and seed production are achieved.

Since the chances of a pollen grain reaching an ideal mate are slim, plants tend to produce a lot of pollen. And as we know, and even suffer, this overproduction has consequences that go beyond plant reproduction.

Love is in the air

Pollen production is finely orchestrated by environmental conditions such as temperature, humidity, and light, as well as the plant’s hormonal status. But also, the dance of pollinators around the plant can also encourage pollen production. As the pollinator moves from flower to flower in search of nectar, its body is loading and unloading pollen grains that are deposited on the pistils of the flowers (specifically in the stigmata), increasing the possibility of fertilization and seed formation. Indeed, in plants, love is in the air.

To increase reproductive success, plants have been creating an astonishing variety of structures, shapes, and colors for their pollen grains, which are closely related. with dispersal mechanisms and pollinators.

Thus, the most visible and heavy pollen grains, and also those provided with small spines and a sticky surface, are generally transported on the backs of large pollinators such as bees (entomophilia) and birds (ornithophilia). Instead, those smaller, lighter, spherical and winged are carried by the spring breezel (anemophilia).

Pigments such as flavonoids and/or carotenoids are behind the reddish-bluish and/or yellow-orange color so common in pollen grains, which makes them even more attractive to pollinators. Furthermore, it should not be forgotten that, together with the nectar, andPollen is also collected by pollinators as food rich in proteins, lipids, and carbohydrates.

What would the world be without pollen?

Pollen plays a crucial role in agriculture, especially in the production of fruits, vegetables and grains. It is estimated that more than 75% of crops Food in the world depends to some extent on pollination (transfer of pollen). Therefore, a large part of our diet is at stake. each seed, grain and fruit that we eat is a direct product of pollination.

Without pollination, crops would not produce viable seeds, which would reduce their yield and lead to significant economic losses. In a scenario of high demand for food due to the increase in the world population, we cannot despise pollen or the work of pollinators.

As pollinating agents, bees, butterflies, birds, moths, beetles and even bats influence the stability and plant diversity of ecosystems and in the yield (quantity and nutritional quality) of crops in the agroecosystems.

No matter how small the pollen grains and pollinators are, play a major role in achieving several of the Sustainable Development Goals (SDGs) set by the UN from the fight against hunger and poverty to job creation and economic growth.

The perfect storm on a planetary scale

Unfortunately, the fragmentation and destruction of habitats, the use of pesticides and the climate change are causing the perfect storm on a planetary scale: a decrease in plant diversity, reduction in pollen quality and decline in populations pollinators.

What can we do? Restoring and conserving habitats, restricting pesticide use, enhancing biological pest control, and diversifying farms to create a balanced ecosystem for bees and their fellow pollinators. We have a lot of work ahead of us.

Maria Teresa Gomez SagastiAdjunct professor and researcher in the Plant Physiology area, University of the Basque Country / Euskal Herriko Unibertsitatea

This article was originally published on The Conversation. read the original.