Most people consider pollen to be some kind of sticky yellow substance that scatters in all directions in the spring and summer. Thanks to pollen, plants are fertilized, but it is also a fundamental factor in the survival of many plant species. With its help, seeds, fruits and the same allergy appear, forcing people to sit at home on sunny days. All this is not a secret, but we want to talk about 10 facts that will allow us to learn something new about pollen.
1
It comes in different colors
Although we associate pollen exclusively with yellow, in nature this substance can occur in various colors and shades, including purple, red, brown, and white. But most of it is still yellow (in some cases blue). This is due to the fact that some insects (bees) “fertilizers” do not perceive red shades, responding better to yellow. However, it is not without exceptions, for example, for butterflies and birds, the best irritant are pollen grains of red color, to which they fly with great desire.
2
Some allergies are caused by hypersensitivity to pollen.
Plant pollen is a potent allergen that causes severe discomfort through allergic reactions. Microscopic pollen grains carrying a specific type of protein are often the cause of allergy symptoms. Although they do not cause harm, some people may react sharply to contact with them because of hypersensitivity to substances of this kind. The B cells responsible for the immune system produce special antibodies in response to contact with pollen. With excessive production of antibodies, other types of leukocytes (mast cells and basophils) are activated, which produce histamine, which dilates blood vessels and causes all known manifestations of allergies, including redness and swelling around the eyes, as well as nasal congestion.
3
Not all pollen causes allergies
Due to the huge amount of pollen produced by flowering plants, it seems that any such plant during flowering can cause an allergic reaction. However, the salt is that pollen is mainly spread by insects, not by wind. Therefore, the pollen of plants carrying it with the help of "couriers" will not cause you allergies. The danger is represented by plants that prefer to cope with the distribution of pollen grains, for example, ragweed, maple, elm and some herbs. They resort to the help of the wind, simultaneously causing allergies in people.
4
To spread pollen, plants have to trick
Plants can use various tricks to lure pollen insects. Light pollen is best seen in the dark, attracting moths and other nocturnal insects. Low-growing plants rely on creeping insects that cannot fly (beetles, ants). In addition to external factors, plants also pay attention to the smell of insects, producing pollen with a rotten odor that attracts flies. The flowers of some plants in their shape and color may resemble female insects of certain species, which makes them attractive to males. Trying to mate with the “model” of the female, the male pollinates a cunning plant.
And in the insect world there are very unusual specimens. You can read about them on our site thebiggest.ru, simply by clicking on the link.
5
Plants can be pollinated by insects of various sizes.
When we talk about pollinating insects, we usually represent bees. However, a number of other insects (flies, butterflies, bugs, ants, etc.) and even animals (bats, hummingbirds) also carry pollen. The smallest carriers are bees from the family of andrenides and a fig wasp. Blastophaga psenes, a female fig wasp, grows in length no more than 15 mm.
One of the largest pollinating animals is the black and white colored lemur vari found in Madagascar. He uses his elongated stigma to get to flower nectar, transferring pollen from one plant to another.
6
Pollen is the male sex cell
At its core, pollen is the male sperm responsible for the production of plant gametophyte. Each grain contains both unproductive cells called vegetative cells and reproductive or generative cells. Plants with flowers produce pollen in a special duster located in the flower stamen. Coniferous species produce pollen in a pollen cone.
By the way, there is an interesting article about the biggest flowers in the world on TheBiggest.ru.
7
Grains paving a tunnel for pollination
To carry out pollination, pollen grains must penetrate into the female part (carpel) of the plant. It is important that the plant was of a similar type to the one in which the pollen was developed. In flowering species, it is collected by the stigmatic part of carpel. Vegetative cells in pollen grains create a pollen tube, which is used as a tunnel to move pollen from stigma to the ovary along the long stem of the carpel. After dividing the generative cell, two spermatozoa form, moving along the pollen tunnel into the egg cell of the plant. Often, such transitions take about two days, but some sperm are not in a hurry, reaching the ovary only after a couple of months.
8
Pollen is necessary not only for self-pollination, but also for cross-pollination
Flowers possessing both female (gynoecium) and male (pestle) parts can perform not only self-pollination, but also cross-fertilization. Self-pollination involves the combination of sperm with an egg in the female part of the same plant. Cross-pollination is characterized by the transfer of pollen from the male part of the flower to the female part of another, genetically similar. This type of pollination helps to develop various types of plants and improve their adaptation to the external environment.
9
Some plants use toxins to prevent self-pollination.
Certain species of flowering plants have molecular self-determination systems that prevent the process of self-fertilization. This is due to the automatic “rejection” of pollen from a similar plant. As soon as the grain is identified as "own", it is blocked from penetration. Some plants have a toxin that penetrates the pollen tube to poison it. If pollen has a similar “genetic code” to a pistil or carpel, the toxins prevent their bonding.
10
Pollen refers to powdered spores
For the first time, the term pollen was used by Karl Linnaeus in the second half of the 18th century, who is the inventor of the classification of binomial nomenclature. This botanical term refers to the "fertilizing element of plants" and stands for "microscopic grains or spores, yellowish in powder form."
Finally
This is where we finish talking about pollen. TheBiggest.ru hopes that we managed to expand your horizons a little with useful and interesting information. We are looking forward to hearing your thoughts on the topic in the comments.
Author: Maxim Svistunov