rooting in water

Hi,

Plants rely on passive transport of oxygen through their root systems. Many plants will surely die if their roots are too wet, which essentially smothers them. Roots must not be the sole area responsible for oxygen diffusion. I am posing this for two reasons.

1. Cuttings that are being rooted do not die from oxygen deprivation and they are rootless for a period of time.

2. Some cuttings will root in plain water and they do not smother, so why do they drown in the ground?


I'll go for two discussion points here:
Next, any suggestions for best liquid/get rooting hormone? I used powder this year and had great success with it but the idea of not having to sterilize the liquid types intrigues me.

Thanks!

Good questions, and I'm surprised there isn't a flurry of responses.

Regarding "water roots," I'll quote Al (Tapla), whose explanation is as good as any other I've seen:

Regarding oxygen...the leaves both take up oxygen during respiration and release it as a product of photosynthesis.

Not sure what you mean by sterilizing the liquid types...I use both powder and IBA solution (from tablets) with good success without sterilizing anything but my knife.

Very good info in the quote. Thanks!

I expected the flurry also. I assume the absence therof reflects the complexity of the issue...maybe we all stand a good chance of learning something worthwhile here...

"Regarding oxygen...the leaves both take up oxygen during respiration and release it as a product of photosynthesis."

This helps promote the question at hand. If this is so, and plants can obtain oxygen through their leaves, how could we smother plants with too much water?

This is the explanation I would offer:

Excessive watering promotes the growth of soil-borne fungi and other pathogens that attack and kill the roots...root rot. I suspect there might be a direct hypoxic effect as well.

As I remember the "water rooters" were adding hydrogren peroxide to the tanks as well as using aquarium oxygenators (from the Walmart goldfish department). Also, the instructions were to change the water often and to transfer the cuttings to potting soil as soon as roots had formed. In my experience, if you leave the cuttings in water without supplying oxygen in some form the cuttings die. In Tapla's excellent article on potting soil he makes a big point of adding perlite and bark to maintain air in the soil as well as not blocking the water table that forms inside the pot. I think this article is the sticky to the container gardening forum.