How do roots avoid getting clogged

[Naty1]

Plant roots absorb water and nutrients for the life of the plant. What keeps the exterior surface of the root cells from becoming clogged...say with dirt or other matter. Any filter eventually becomes clogged and needs to be cleaned, how about plant roots?

One possibility is that surface cells die and decompose freeing up new clean cells to do the job...

 

[jim mcnamara]

The uptake of water and nutrients by roots occurs through

1. root hairs, which are VERY small compared to most soil particles. This is not like the action of a seive or a strainer or filter paper, it is through cell membranes, which work at the level of molecules, not soil particles.

2. symbiotic fungal filaments (Ex. Pine tree) - which work very much like root hairs, and the same rules apply - they work at the molecular level.

So, your basic assumption is not good - that there is some kind of "buildup" of goo or mud on the roots.

 

[Naty1]

Thanks for the reply...I just checked Wikipedia which had some insights..here is one :

As secondary xylem accumulates, the "girth" (lateral dimensions) of the stem and root increases. As a result, tissues beyond the secondary phloem (including the epidermis and cortex, in many cases) tend to be pushed outward and are eventually "sloughed off" (shed).

 

[Monique]

As jim mcnamara mentioned, the notion that the cells get clogged by dirt or matter is not really a correct one. The root does shed cells, a process that occurs in your skin and in your intestine as well. It might be that the cells that are exposed to the environment are more likely to become damaged and that's why there is a continual process of renewal.

I do wonder along what part of the root this shedding occurs. The stem cells of the root are located in the very tip and this is where most of the growth and mitotic activity occurs.

This video might be interesting to you: http://www.scivee.tv/node/10103
This researcher studies the stem cells and the growth that occurs in the plant root (he's a leader in the field).

 

[nismaratwork]

The uptake of water and nutrients by roots occurs through

1. root hairs, which are VERY small compared to most soil particles. This is not like the action of a seive or a strainer or filter paper, it is through cell membranes, which work at the level of molecules, not soil particles.

2. symbiotic fungal filaments (Ex. Pine tree) - which work very much like root hairs, and the same rules apply - they work at the molecular level.

So, your basic assumption is not good - that there is some kind of "buildup" of goo or mud on the roots.

For the sake of trivia, some of those fungi are... truffles! Roots and fungi are almost inseparable, it seems, the more this is studied. For the clogging, just consider (reverse and regular) osmosis, but in the case of a living system you have constant replacement at the cellular level instead of bulk replacement of a whole filter.

Monique: This leads to the answer to your question: Shedding occurs most just behind the tip, and in general in the smallest and most numerous filaments.