why do plants need to be pollinated


(http://commons. wikimedia. org/wiki/File:Pollen_from_Fijian_Flower_close-up. jpg) Overview
Plants with flowers need pollination to create new seeds that will grow into new plants. The flower of a plant is usually where reproduction occurs, so without pollination a flower cannot reproduce. Of the 300,000 plant species on this planet that produce pollen, each type makes pollen unique only to that plant, according to National Geographic. Stamen The stamen is the male part of a flower the reproductive organ that produces the sticky powder known as pollen. The stamen is made up of a filament that holds the anther. The filament is a thin stalk. An anther sits on the tip of each filament and contains the pollen, which is the plant s male reproductive cell. Pollen fertilizes the ovules or female reproductive cells of the plant. Fertilization results in the formation of seeds. Pistil The pistil is the female part of a flower, consisting of the stigma, style, ovary and ovule. The stigma is the part of the flower that receives the pollen during fertilization. It sits on top of the pistil and is sticky in order to catch the pollen. The style is a tube that extends out the top of the ovary. This tube transports the reproductive cells in pollen from the stigma to the ovules. The ovary is the female reproductive organ of the plant that holds the ovules, which are the female reproductive cells located in the base of the pistil. An ovule is a tiny egg that becomes the seed once it has been fertilized with pollen. The Process of Pollination For pollination to occur, pollen must be transferred from the plant s stamen to its stigma.


This process is referred to as self-pollination. If pollen from one plant s stamen is transferred to the stigma of a different plant of the same species, cross-pollination occurs. Cross-pollination is better than self-pollination because it produces stronger plants. However, the pollen from a different species plant will not work. Once ovules in a plant are fertilized with pollen, the ovules develop into fruit. The fruit covers the seeds, which eventually become new plants. Pollinators Plants get pollinated in several different ways. The most common method of pollination takes place when birds or insects such as bees, flies, moths or butterflies try to get pollen or nectar from the plant. Flowers that are brightly colored or have a strong fragrance attract hummingbirds and insects as pollinators, although beetles and bats can spread pollen as well. When a pollinator lands on a plant, pollen from the plant s stamen can get on its legs or body, so that when the bird or insect moves on to another flower, it carries pollen grains to that plant s stigma. What are pollinators? Pollinators are animals that move pollen from male structures (anthers) of flowers to the female structure (stigma) of the same plant species. P Movement of pollen (analogous to sperm) to a flowers stigma results in fertilization of the flowers eggs. P An adequately fertilized flower will produce seeds and the fruit surrounding seeds, ensuring that a new generation of plants can be grown.


P Pollination is mutually beneficial to plants and to pollinators. P Pollination results in the production of seeds and is necessary for many plants to reproduce. Meanwhile, pollinators receive nectar and/or pollen rewards from the flowers that they visit. P Sugary nectar provides pollinators with carbohydrates while pollen offers proteins, fats, vitamins, minerals, and necessary phytochemicals. See [1] for a recent review of bee nutritional needs. Examples of pollinators Honey bees often come to mind first when people think of pollinators. However, many different animals, including other insects (other bee species, butterflies, beetles, flies), some birds and some bats are pollinators. Indeed, there are an estimated 300,000 species of flowering plants worldwide that require animal pollinators [2]. This tremendous floral variety supports a corresponding diversity of pollinators, and the vast majority of these pollinators are insects. P For example, while there are only about 1,000 vertebrate pollinator species, its estimated that there are at least 16,000 different species of bees world-wide [3]. P Pollinators are necessary for three-quarters of our major food crops Not every species of plant requires animal-mediated pollination services. For example, wheat is wind-pollinated. However, the majority of crops that we like most to eat and provide most of our nutrition (fruits, vegetables, and nuts) use animal-mediated pollination [4, 5]. Without pollinators, our diets would be severely limited, and it would be more difficult to acquire the variety of vitamins and minerals that we need to stay healthy.


P Healthy pollinators and healthy ecosystems Outside of agricultural systems, approximately 80-95% of the plant species found in natural habitats require animal-mediated pollination [2]. Plants are the foundation of terrestrial food chains. The foliage and/or fruits and nuts that plants make are eaten by herbivores which in turn are hunted by predators. Furthermore, plants provide shelter and nesting habitat for many different animal species. Thus, in order to maintain the diversity of our natural ecosystems, we need healthy pollinator populations to ensure that the next generation of plants will be produced. P P [1] Vaudo, A. D, Tooker, J. F. , Grozinger, C. M. and H. M. Patch. \” Bee nutrition and floral resource restoration. \” Current Opinion in Insect Science 10:133-141 (2015). [2] Ollerton J, Winfree R, Tarrant S: How many flowering plants are pollinated by animals? Oikos 2011, 120(3):321-326. [3] Danforth BN, Sipes S, Fang J, Brady SG: The history of early bee diversification based on five genes plus morphology. Proceedings of the National Academy of Sciences of the United States of America 2006, 103(41):15118-15123. [4] Klein, A-M, et al. \” The importance of pollinators in changing landscapes for world crops \”. Proceedings of the Royal Society B 274 (1608): 303-313. [5] Eilers, E. J. et al. \” Contribution of Pollinator-Mediated Crops to Nutrients in the Human Food Supply \” PLoS One 6(6): e21363. doi:10. 1371/journal. pone. 0021363

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