Plant Hormone

1. Auxins
This hormone is important during growth in plants because it is what keeps the roots and stem growing length wise. This hormone is released based on environmental factors like sunlight, water, and animals. Auxin is sent around the plant via cell to cell transportation. to make the stem "lean" a certain way it causes one side of the stem to grow longer cells that curve over the shorter cells below.
2. Abscisic Acid
Abscisic acid works opposite of the auxins in a plant by stopping growth when the plant does not have enough energy or needs to use it elsewhere. This is important to plants so that they don't keep trying to grow without adequate energy.
3. Ethylene
Ethylene is a gas that cause fruit to ripen in fruit bearing plants. This can be seen in banana's browning, apples getting mushy, and avocados getting softer. Fruit ripens in a contained environment because the gas can not escape.