Auxin Magazine

PLANT HORMONES: AUXIN By: Macarena Ramos, Agustín Herrera & José Ignacio Chávez 10-­‐C 11/November/2015

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Production – What is it ………………………. Pg. 3 Movement ……………………………………. Pg. 4 History of Auxin ……………………………... Pg. 5 Humans & Implications ……………………… Pg. 6 Works Cited ………………………………….. Pg. 7

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Auxin is the first plant hormone identified. It plays an important role in cell elongation and growth in the SAM and RAM of the plant.

Stimulates the differentiation of xylem and phloem • It is produced in the terminal buns and instead of making the side buns grow it is in charge of the root’s an stem’s growth • The plant naturally produces it or it will die • It is developed in the shoot tips, embryos, parts of flowers and seeds soon to germinate • Produced in order to help with cell elongation o Cells grow larger in the darker part of the plant

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• It is transported from cell to cell through the Parenchyma • Transported in one direction going from the stem tip to the roots o Therefore, there is more concentration of it on the stem tip and less as it travels down to the roots • Auxin will move to the part of the plant that doesn’t receive light and elongate those cells • This will cause the plant to start bending and growing towards the sun (Phototropism)

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• Auxin was the first hormone discovered • Charles Darwin was one of the first scientists to study plant hormones o He did and experiment and found auxin • In his book “The Power of Movement in Plants” he talked about the movement of coleoptiles • He studied how unidirectional light shinning on the coleoptile made it bend towards the light • If the tip was covered with aluminum foil the plant wouldn’t bend • However if the tip wasn’t covered but below the tip it was, it will still bended towards the light • In 1926 – Frits Went proved that auxin existed after Darwin’s experiment

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• In the case of the apex of the shoot being removed by a human the plant is no longer able to produce auxin • Due to that, the lateral buns will break their dormancy and start to grow causing… o Apical

dominance

would

not

be

maintained o It would grow “bushier” • Some farmers spray artificial auxin in the plants to make them bigger (apples & pears) • Tomato plant can also be sprayed in order to make the plant produce more fruit

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"Word! Hormones." KidsHealth - the Web's Most Visited Site about Children's Health.

The Nemours Foundation, n.d. Web. 03 Nov. 2015. <http://kidshealth.org/kid/word/h/word_hormones.html>.

"Plant Growth Factors: Plant Hormones." Plant Growth Factors: Plant Hormones. N.p., n.d. Web. 04 Nov. 2015. <http://www.ext.colostate.edu/mg/gardennotes/145.html>.

Nelson, Rob. "Plant Growth Hormones." Untamed Science. N.p., n.d. Web. <http://www.untamedscience.com/biology/plants/plant-growth-hormones/>.

"Types of Plant Hormones." Cliffs Notes. Houghton Mifflin Harcourt, n.d. Web. <http://www.cliffsnotes.com/study-guides/biology/plant-biology/growth-ofplants/types-of-plant-hormones>.

"PLANT HORMONES, NUTRITION, AND TRANSPORT." Plant Hormones/Nutrition. N.p., n.d. Web. <http://www2.estrellamountain.edu/faculty/farabee/Biobk/BioBookPLANTHOR M.html>.

"Auxins." The International Plant Growth Substances Association. Washington University in St. Louis, n.d. Web. <http://pages.wustl.edu/ipgsa/auxins>.

Koning, Ross E. "The Discovery of Auxins: Phototropism." Auxins. N.p., n.d. Web. 10 Nov. 2015. <http://plantphys.info/plant_physiology/auxin.shtml>.

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