Plant Hormones!

Plant Hormones!

Auxins:

Hormones in the plant that serves many functions. They are like the growth hormone of the plant by stimulating stem elongation and softening of cell wall. The most common naturally occurring auxin is Indoleacetic acid (IAA). Auxins spur the growth of the plant, and boosts root growing speed. Other functions of the auxin includes enhancing apical dominance, where a plant will prefer to grow towards the direction of the sun vertically rather than laterally.

Abscisic Acid (ABA):

These hormones maintains plant health and homeostasis during shifting environmental factors. It serves as a counter-hormone to Auxins by inhibiting growth and promoting seed dormancy. Furthermore, during times of drought or low water availability, it allows the plants to survive by closing the stomates.

Ethylene:

The unusual thing about this hormone is that it is a gas. It functions under positive feedback and it promotes ripening of fruit. Once a fruit ripens, there is also a increased production of ethylene gas. When there is a barrel of apples, and one apple became ripe, the whole barrel will soon go bad due to the ethylene gas triggering faster ripening in the other apples. Hence the old adage "One bad apple spoils the whole barrel."