Then they measure the amount of antibodies your blood produces to attack the allergens. As with skin testing, a positive blood test to an allergen does not necessarily mean that an allergen caused your symptoms. Look for this mark to find products proven more suitable for people with asthma and allergies.
Many people with pollen allergy do not get complete relief from medications. This means they may be candidates for immunotherapy. Immunotherapy is a long-term treatment that can help prevent or reduce the severity of allergic reactions. SCIT is a series of shots that have progressively larger amounts of allergen. An injection of the allergen goes into the fat under the skin.
Over time, allergic symptoms generally improve. Many patients experience complete relief within one to three years of starting SCIT. Many people experience benefits for at least several years after the shots stop. Sublingual Immunotherapy involves placing a tablet containing the allergen under the tongue for 1 to 2 minutes and then swallowing it.
In , the FDA approved three types of under-the-tongue tablets to treat grass and ragweed allergies. These plants make small, light, and dry pollen grains that are made to be carried by wind. Amazingly, scientists have collected samples of ragweed pollen miles out at sea and 2 miles high in the air. In addition, most allergy-causing pollen comes from plants that produce it in huge quantities.
For example, a single ragweed plant can generate a million grains of pollen every day. The components of a pollen grain are the main factors that determine whether that pollen is likely to cause allergic rhinitis.
For example, pine tree pollen is produced in large amounts by a common tree, but it is not a major cause of pollen allergy because the components of pine pollen are less likely to cause an allergic reaction. Some grasses that produce pollen -Timothy grass -Kentucky bluegrass -Johnson grass -Bermuda grass -Redtop grass -Orchard grass -Sweet vernal grass.
Among North American plants, weeds produce the largest amounts of allergenic pollen. Some species of grasses and trees also produce highly allergenic pollen. Only florists, gardeners, and others who have close contact with flowers over a long period of time are likely to be sensitive to pollen from these plants. In fact, most people have little contact with the large, heavy, and waxy pollen grains of flowering plants because this type of pollen is not carried by wind, but by insects such as butterflies and bees.
When Do Plants Make Pollen? One of the obvious features of pollen allergy is its seasonal nature—people have symptoms only when the pollen grains to which they are allergic are in the air. By: Jessika Toothman. Plants evolved pollen as a reproductive means more than million years ago, and since then, they haven't looked back [source: Dunn ]. A large portion of the plant life that's spread far and wide across the planet today displays this evolutionary ingenuity.
The main reason pollen -- and by extension the process of pollination -- is so important, is because it means plants don't have to rely on water to transport the biological components necessary for fertilization. Plants that bear pollen also tend to offer protection to their offspring after fertilization in the form of hard seeds -- and in some cases, those seeds are even nestled inside fleshy fruits.
Pollen grains are, in essence, plant sperm. Or perhaps more technically, sperm sedans. Inside, they contain the male portion of DNA needed for plant reproduction. There's great variation when it comes to the size of pollen grains, and there's no correlation between the size of the plant and the size of the pollen it produces. Large plants might generate some of the tiniest grains of pollen, while diminutive plants may yield pollen that puts those to shame.
Pollen grains may not look like much; to the naked eye, they often look like dusty specks, but upon closer inspection, they take an endless array of fascinating shapes with all manner of textures and features.
Whether conical, spherical, cylindrical or some other fantastical shape, many grains of pollen resemble something else, be it coral, succulent, seashell or sea anemone. Some grains are dotted with little spikes; others have weblike surfaces. Still more appear enshrined in ropey tangles, while others sport delicate dimples or have ribs that resemble the stripes on a watermelon. Many of these unique adaptations are to help the pollen get where it needs to go -- namely, its own species' female counterpart.
Surface features help grains cling to different modes of transportation, such as bird feathers, bee legs or animal fur. Or they help pollen sail through the air on appendages that resemble airplane wings or hot air balloons. Some of these features even help a pollen grain perform successfully when it reaches its destination. We'll discuss what happens when that happy event occurs on the next page.
In most pollen-producing plants, a grain of pollen successfully completes its journey when it travels from the male portion of a plant specimen to the corresponding female portion. Ideally, it finds its way to an entirely different plant to increase outcrossing borne from crosspollination. That's not always a hard and fast requirement, however, although it's important to note that many plant species have ways to prevent a particular plant from pollinating itself.
Some are even genetically self-incompatible. Once a grain of pollen reaches the plant's female portion, in most cases an ovule , one of the lucky sperm typically out of two lodged within the pollen will fertilize the egg cell inside. After fertilization occurs, the ovule will gradually develop into a seed , and that seed will transport its embryonic plant to a new home.
Plants that follow this basic reproductive path are known as gymnosperms. Trees that have pinecones and similar reproductive structures, as is the case with most conifers, are examples of gymnosperms. Let's take a closer look at conifers , the most numerous and widespread gymnosperms on Earth today, and pines in particular, since they're some of the most familiar species. Pinecones generally come in male and female varieties, and they can be all sorts of shapes, textures and sizes, depending on the species.
One makes the pollen, and the other receives it. Once a pollen grain arrives at an ovule -- usually adhering with the help of a sticky substance produced by the female pinecone -- it absorbs water, germinates and starts slowly growing a pollen tube in order to place the newly generated sperm inside. Fertilization occurs, and a seed eventually forms. The length of time it takes for the overall process to complete itself varies greatly; in many pine species, the pollination process takes more than a year from start to finish.
Once it's finished, the seed is liberated from the cone, to travel on its way. But although the development of the pollination process was revolutionary, it still had some kinks that could be worked out. On the next page, we'll take a look at the plants who whipped out the evolutionary iron and made the method that much more reliable. Many people suffer from allergic rhinitis , and pollen is a big contributor.
Different plant species produce different pollens, and those different pollens are composed of different buffets of proteins. Some of those proteins cause allergy sufferers' immune systems to go into overdrive. Some plants -- the angiosperms -- evolved to take the pollination process a step further.
These are the flowering plants, and not only do they produce seeds, they also flower and produce protective fruits.
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