Plant puberty

Date posted: 30 September 2013

Take a look at the barley crop growing in the Botanic Gardens. While the plants may not look particularly exciting with no flowers or grains to see, the plant is actually going through a very important development phase – stem extension.  

Puberty barley-style

This phase is almost the equivalent of the plant going through puberty! While the plant doesn’t get pimples, it begins to go through fundamental growth and developmental changes.  

The plant also moves from its vegetative growth phase (that is, it has been focusing on growing vegetation such as leaves and stems) to reproductive growth (where the reproductive organs, including the ovules and anthers, form in the developing ear).  From here, we look forward to the heading phase where we see the grain starting to form...

Stretching up and up and up…

The plant goes through a large growth spurt where the stems elongate. This process pushes the ‘ear’ of the barley plant towards the top of the crop where it will later emerge and produce the grains.  As the plant elongates, the nodes stretch apart (making the internode longer).  

If you rub your hands along the stems you can feel the nodes, they are like a small bump along the stem where a new leaf or stem joins. Note that the space between nodes it known as the internode. 

Activity: Be an agronomist! 

Visit the crop in the Botanic Gardens and take a few measurements and observations. 
  1. Count the number of tillers on 10 plants. Calculate the average number of tillers per plant.
  2. Look closely at the stem of the plants. See if you can pick the nodes? How long are the internode spaces?