Pollen

Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of helping plants reproduce. It consists of tiny pollen grains, which carry the male cells needed for creating new plants.

Pollen grains have a tough outer coating that protects them as they travel from the part of the flower that makes pollen to the part that can receive it. If a pollen grain lands on the right place, it starts to grow a tube that carries the male cells to meet the female cells, allowing the plant to make seeds.

The study of pollen is called palynology and it helps scientists learn about the past, study ancient plants, and even solve crimes. Pollen can also be used as a food supplement, though it sometimes contains traces of farm chemicals.

Structure and formation

Pollen is a special dust made by flowers and some other plants. It is not the male part itself but a tiny helper that carries that part. Each pollen grain has cells that help it move and a cell that becomes the male part when it finds the right flower.

Pollen grains come in many shapes and sizes, each type of plant having its own look. Some are round, some are long, and some even have little wings. For example, pollen from pine trees has wings, while forget-me-not flowers make very tiny pollen grains. The outside of pollen is very strong, which helps protect it on its journey.

Pollination

Main article: Pollination

Pollination is when pollen grains move to the female part of a plant, called the pistil. This can happen in a few ways. One way is by wind. Plants that use wind to carry their pollen often make lots of very light pollen. These are called anemophilous plants.

Some plants need help from insects or other small creatures to move their pollen. These plants make pollen that is heavier and stickier, which attracts insects and other pollinators. These plants are called entomophilous. Many insects eat pollen and are known as palynivores.

In the fossil record

Main article: Palynology

Pollen has a special outer coating that helps it survive over very long times, even when other things break down. Because of this, scientists can find pollen in old rock layers and study it. This helps them learn about plants that lived long ago and even what the weather was like back then. We first start seeing pollen in rocks from a very old time called the Devonian period, though it looked a bit different back then. Since then, the amount of pollen we find has grown a lot.

Allergy to pollen

See also: Allergy season

Nasal allergy to pollen is called pollinosis, and allergy specifically to grass pollen is called hay fever. Pollen that causes allergies often comes from plants that spread their pollen through the wind. These plants make lots of lightweight pollen that can travel far and get into our noses.

Pollen allergies are common in places with cold and warm seasons, but less so in tropical areas. In northern Europe, birch and alder pollen are common triggers, while in the US, many people think goldenrod causes allergies, but it's actually ragweed. Symptoms of pollen allergies include sneezing, a runny or itchy nose, and watery, itchy eyes. These symptoms can sometimes lead to asthma attacks.

The number of people in the United States with hay fever is between 20 and 40 million, including around 6.1 million children. Treating pollen allergies often means avoiding pollen when possible. Medicines like antihistamines and decongestants can help with symptoms. There is also a treatment called allergy immunotherapy that helps the body get used to pollen over time.

Nutrition

Many animals eat pollen. While bees are well-known for eating pollen, other insects like spiders, beetles, and flies also enjoy it. Some spiders catch pollen on their webs, and certain beetles eat almost only pollen. Even some mites and fungi can use pollen as a food source.

In humans, bee pollen is sometimes eaten as a food or supplement. It contains carbohydrates and protein, but the U.S. Food and Drug Administration says there is no strong proof that it has special health benefits. People should be careful because pollen can cause allergies or contain harmful substances if not stored properly.

Forensic palynology

Main article: Forensic palynology

In science, pollen can help figure out where a person or object has been. Different places, like certain bushes or areas of the world, have their own special mix of pollen. This helps experts learn important clues. For example, pollen has been used to study places from history and even help solve mysteries by showing where someone might have walked or brushed against plants.

Spiritual purposes

In some Native American religions, pollen was used in prayers and rituals to represent life and new beginnings. It helped make objects, dancing areas, paths, and sandpaintings special. It could also be sprinkled on people's heads or in their mouths. Many Navajo people thought that walking on a path with pollen made the body feel holy.

Pollen grain staining

Scientists sometimes need to check if pollen grains are healthy or not, especially for farming research. One common way to do this is called Alexander's stain. This special mix of liquids can show if a pollen grain is working well. Healthy pollen grains turn red or pink, while the ones that are not working turn blue or a little green. There is also a safer version of this mix that leaves out some of the stronger ingredients.