Auxins are plant hormones that regulate cell growth and development.
Auxins are found at the tips of twigs, roots, and buds. Auxins are the reason roots go down and stems go up. They also restrict buds lower down the stem from developing. When these tips are cut off, lateral bud development further down the stem increases, which means more fruit or flowers.
Many herbicides are actually synthetic plant hormones that force a plant to grow so fast that it dies.
Auxins travel through the stem downward, through the phloem, so gardeners can bend branches into a more horizontal position to reduce auxin levels and stimulate lateral bud growth.
You can grow a surprising amount of food in your own yard. Ask me how!