Uses of Plant Hormones | Biology for All | FuseSchool

In this video we are going to look at a few different ways in which plant hormones can be used. Plant growth hormones (auxins) can be used as selective weedkillers. The selective weedkillers contain growth hormones, that cause the weeds to grow really quickly. This means the weed is absorbing nutrients from the soil at a much higher rate, and so the weeds absorb the weedkiller in much larger quantities than beneficial plants. This can be used for getting rid of weeds without killing the grass, or thistles in a field without killing the crop. But they aren’t just good at killing plants. Gardeners use growth hormones to promote growth. They take cuttings of plants and dip the stalk end into rooting powder which contains growth hormones. This makes stem cuttings quickly develop roots and establish as functioning plants. Plant hormones can also be used in controlling fruit ripening. Some slow it down, and others speed it up. We can make use of this knowledge to inhibit hormones during transport so that the fruit does not ripen too quickly, or we can promote ripening when in the shops so it is in perfect condition for consumers. Bite into a banana, and you don’t expect seeds do you? Hormones sprayed onto flowers can stop seeds developing, leaving us with big, juicy, seedless fruits. In nature, plants only germinate when conditions are ideal for growth. This is called seed dormancy and is controlled by hormones. We can use hormones and inhibitors to remove the dormancy of seeds, thus enabling us to germinate seeds at all times of the year. We can also use these hormones to make plants grow bushier and make them flower at controlled times; exactly what you want if you are entering a flower show! Ethylene is used to ripen fruit. Ethylene breaks down components of the cell walls to make them softer, and makes them sweeter by converting starches to sugars. Ever wondered why you are told to put unripe fruit next to ripe fruit? Ethylene is different to other hormones because it is an airborne gas, and works on a positive feedback loop. Start with a little ethylene, and this causes more to be released, which causes more to be released… and so on. Therefore promoting ripening in all ‘local’ fruit. Our teachers and animators come together to make fun & easy-to-understand videos in Chemistry, Biology, Physics, Maths & ICT. VISIT us at, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you. These videos can be used in a flipped classroom model or as a revision aid. Twitter: Access a deeper Learning Experience in the FuseSchool platform and app: Friend us: This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us: Click here to see more videos:

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