Auxin, Top Boss in Plant Growth

In any system there has to be a stopping point. In crop plant production, that stopping point is Auxin (IAA – indole-3-acetic acid).

Why is it important to understand this?

  • To put more money in your pockets
  • Larger yields with more knowledge and understanding
  • Better use of the land and resources
  • Better crop quality

The plant brain or root tip is able to respond to the environment in the soil, air, and plant. Auxin has the final say in what happens in the plant. It is the main regulating hormone in plant growth, and has a huge number of advisors and messengers. Although there is much still not known today about these hormones, there is an understanding of at least some of them. Four main hormones are ABA, Gibberellin, Cytokinin and Ethylene. Naturally there are a huge number of other molecules and minerals that have to be available for growth before auxin can have its regulating effect.

Auxin responds to the whole host of advisors and then regulates growth depending on the information it receives. For example, ABA is the plant’s comptroller. ABA advises that there are only so many resources to do the job under the environmental conditions that are perceived.

Because Auxin is the most important it can over ride ABA. This is where growers come in. The plant regulates itself to survive until its cycle is complete. It is programmed to be very conservative. Therefore it will change to whatever growth type it naturally responds to, even if it means reducing the part of the plant that has economic importance to the grower.

An example of how to stop this change is to understand that the natural tendency of a plant is to reduce or even stop growth at temperatures that are too cool or too hot. The optimal temperature for growth is between 68F (about 20C) and 90F (about 30C). If it is above or below this temperature the plant needs help. You can assist the plant with products such as Stimulate or Satisfy.

The critical thing to understand is that the concentration of Auxin (IAA) is different in different parts of the plant and in different plant species. Auxin is the highest in concentration in the apex, the tip of the shoot. It is lowest in the root. Each plant species may have slightly different levels, but the basic concept is the same for all plants. It is this Auxin balance that you need to learn.

Auxin really is the top boss, and can be used to improve production and crop quality.