Each node is a collar in waiting

The portion of a plant that connects the shoot to the root is commonly referred to as the collar region. An amazing thing can be noticed in most millets.

As the plant grows, the younger tillers push the older tillers further and further away from the central axis of the plant. At each node in their older tillers, new tillers branch out growing skyward. The parent tiller becomes more and more horizontal and its secondary tillers weigh it down further and further bringing it almost parallel to the ground. From each of the older nodes within these tillers, we see secondary roots being pushed into the ground to bring in the good stuff to grow the plant. Essentially, the older nodes in the senior tillers become a secondary collars !

Secondary roots being pushed at even the 4th node in a browntop millet plant (brachiaria ramosa, ढेंगली (?), ಕೊರ್ಲು, అండు కొర్ర) at a farm near Kadiri, A.P. as captured in this photograph on 20th Oct 2015.

A flourishing Browntop millet plant (Brachiaria Ramosa) photographed in a Proso millet field near Kadiri, A.P. on 20th Oct 2015.

I have seen this in Barnyard, Proso and Browntop millets and given their taxonomy I would expect that Foxtail, Little millets would have a similar behaviour too. While, I suspect that Kodo and Finger millets would be exceptions to this characteristic, I would be more than glad if I am proven wrong !

And they grow taller and taller …

Millets are amazing. Most people would have seen sorghum and pearl millet in the fields growing to more than 8′ in height, and among traditional varieties, 10′ is totally the norm. Some might have noticed how these amazing plants put secondary roots from their collar nodes to support themselves as they grow.

On reaching reproductive stage, the grain filled panicle at the apex of the plant can easily weigh about 300 gms. So, one can approximate the plant to a cylinder with about 2″ to 3″ diameter and a height of 120″, held at one end, with a 300 gm weight at the free end. So its not really surprising that purely from a physical dynamics perspective they put down secondary roots from not just one, or two but even three nodes as seen in this image below. I am sure I am not alone in seeing the many beautiful math and physics concepts that one can explain, demonstrate and possible experiment with in this amazing natural wonder.

Secondary roots of a traditional bi-color variety of Sorghum (సీతమ్మ జొన్న) as seen in a farm in Mandavarapalli, Chittoor Dt., AP. on Oct 19th, 2015.

Dinesh (Earth 360) helping us  estimate the height of the plant whose roots we seen in the image above. (In Mandavarapalli, Chittoor Dt., AP. on Oct 19th, 2015)

And then there is the physiology of the structures. More on that in a later post.