Plant Growth: Auxins and Gibberellins | Plants | Biology | FuseSchool

Plant Growth: Auxins and Gibberellins | Plants | Biology | FuseSchool If a plant has enough water, minerals and energy, it will grow, right? Well, sort of… but there is more to it - like why do plants bend towards the light and not just grow straight? And why does the stem grow up but the roots grow down? It isn’t as if a plant has eyes to tell it where the sun is. Plants are packed full of hormones, sending messages around to its different parts. Where humans have the creatively named ‘growth hormone’, plants have hormones called auxins. Auxin is produced in the stem tips and roots, and controls the direction of growth in response to different stimuli including light and gravity. Having been made in the tips of the stems and roots, auxin is moved in solution by diffusion to older parts of the plant. In the stem, the auxin causes the cells to change in elasticity. More elastic cells absorb more water, and can grow longer. Strangely, though, stems and roots respond differently to